A MANUFACTURE OF THE CONCRETE

TECHNICAL FIELD

[0001] The present application relates to the field of a visual monitoring and quality control of concrete and concrete mixes, their manufacturing process, transportation and handling in a concrete plant and in a construction site, and aggregates and sand collected in a quarry and used in manufacture of the concrete and concrete mixes.

BACKGROUND

[0002] Nowadays, the ready-mixed concrete (RMC) or precast concrete is produced in concrete plants having a certain slump level (which is also called workability) and consistency. During the transportation of the concrete by a concrete mixer truck and while waiting or unloading the concrete or upon production of defected concrete, the slump levels and consistency of the concrete are reduced because of several reasons, such as temperature variations, hydration of the cement, water absorption aggregates, operator mistakes etc. Therefore, it is necessary to constantly add water by truck drivers at construction sites, using expensive chemical admixtures and high dosages of retarders. The use of low quality of concrete, use of concrete mixture different than ordered or desired in the building sites and uncontrolled addition of water into the concrete mixes damages the fresh and harden concrete performances negatively affecting its slump level and consistency.

[0003] Concrete is the most widely used construction material around the world. It is a composite material with a complex structure composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. The concrete mixture composed of aggregates and, sand, while the paste is water and Portland cement and various chemical admixture and chemical additives. Cement normally comprises from 10 to 15 percent of the concrete mix, by weight. Through a process called hydration, the cement and water harden and bind the aggregates into a rock- like mass. This hardening process continues for months meaning that concrete gets harder over time. Portland cement is not a brand name, but the generic term for the type of cement used in virtually all concrete, just as stainless is a type of steel and sterling a type of silver. Therefore, there is no such thing as a cement sidewalk, or a cement mixer; the proper terms are concrete sidewalk and concrete mixer. [0004] At the macroscopic level, concrete may be considered to be a two-phase material, consisting of aggregate particles dispersed in a matrix of the cement paste. At the microscopic level apart from aggregate phase and Hydrated Cement Paste (HCP) phase, a third phase known as the interfacial transition zone (ITZ) comes into picture. In the past few decades, concrete research has been focused on the microscopic level, i.e., the internal microstructure of cement-based materials. The microstructure consists of hardened cement-based materials with residual pore system and generally governs the strength and durability of cement-based materials. The pore system consists of porosity and pore sizes. The pore size characteristics of the porous material are generally represented by pore size distribution either in the form of cumulative pore size distribution or differential pore size distribution. There are many methods to measure the porosity and pore size distribution such as fluid displacement method, helium pycnometer, capillary condensation and adsorption desorption isotherm, small angle x-ray scattering (SAXS) method, scanning electron microscope (SEM), nuclear magnetic resonance (NMR), AC impedance spectroscopy, mercury intrusion porosimetry (MIP) and back scattered electron images (BSE).

[0005] Pores of all types and shapes (gel pores, capillary pores, compaction pores and pores in the interfacial transition zone) and the pore volume affects shear rates of concrete mix, control the strength and physical properties of concrete, and affects workability and consistency, while durability performances are mainly controlled by the interconnected pores. Larger pores are known to have dominant effect on the strength and durability compared to gel pores which are known to affect the shrinkage and creep. Thus, knowledge of porosity and pore size distribution can be used to obtain information on performance of concrete. However, porosity and pore size distribution are governed by factors like water/cement ratio, age and size of cement or cementation particles.

[0006] Other parameters, besides porosity, that affects workability and consistency of the concrete mixtures and therefore, should be monitored while transporting the mixed concrete are: the flow of the concrete in the mixer to indicate its workability level and quality, concrete segregation and bleeding, homogeneity or roughness of concrete, continuity and fluidity of the concrete and its colour.

SUMMARY

[0007] The present application relates to a method for continuous visual monitoring and quality control of aggregates and sand produced in a quarry and used in the preparation of a ready-mix concrete (RMC) or precast concrete, or said RMC or said precast concrete, prepared from said aggregates and sand, said method comprising the following steps: ( 1) Obtaining a visual information on mechanical and physical properties of said aggregates and sand, or physical properties and workability of said RMC or said precast concrete, with an imaging or video camera,

(2) Processing, decoding and performing computational analysis of the visual information obtained in Step (1), with a computing unit to obtain results on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of the RMC or precast concrete,

(3) Analysing and correlating the results of Steps (2) using said computing unit to obtain readable and display able information on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of said RMC or said precast concrete, and

(4) Transmitting said readable or displayable information obtained in Step (3) using a communication module to an external memory or user’s interface in a form of text, graphics or sound signals, thereby updating the user or alerting the user if any action on the user’s side is required.

[0008] In one embodiment, the imaging or video camera, computing unit and communication module are installed in the quarry to perform said method on the aggregates and sand produced in the quarry, to control and monitor the quality of aggregates and sand used for the production of the RMC or precast concrete. The mechanical and physical properties of the aggregates and sand are selected from a particle size and particle size distribution of the aggregates and sand, colour of the aggregates, wetness (amount of moisture in rainy days) of the aggregates and sand, and purity (low content of contaminants) of the aggregates and sand.

[0009] In another embodiment, the imaging or video camera, computing unit and communication module are incorporated into a stationary concrete mixer placed in a concrete plant to perform said method on the RMC or precast concrete, to visually monitor the manufacturing process of the RMC or precast concrete and to control the quality of the produced RMC or precast concrete.

[0010] In a further embodiment, the imaging or video camera, computing unit and communication module are incorporated into a mobile concrete mixer of a concrete truck that transports said RMC or precast concrete from a concrete plant to a construction site, to perform said method on the RMC or precast concrete during the transportation and discharge of the RMC or precast concrete at the construction site. In this case, the information received to the external memory and displayed on the user’s interface is a total volume of the RMC or precast concrete left in the concrete mixer tank of the truck, and it is calculated by the computing unit from an estimated volume discharged (unloaded) by the number of the discharge rounds of the truck. [0011] In yet further embodiment, the imaging/video camera, computing unit and communication module are incorporated into a stationary concrete mixer placed at a construction site to perform said method on the RMC or precast concrete, to control the quality of the RMC or precast concrete obtained from a concrete plant or manufacturer.

[0012] In some embodiments, the method of the present invention may further comprise:

(a) Measuring a hydraulic pressure of the RMC or precast concrete inside the stationary mixer, or inside the concrete mixer tank of the truck transporting said RMC or precast concrete from the concrete plant to the construction site, or inside the stationary mixer installed at the constructions site, with a hydraulic pressure gauge installed on the truck or on any of said stationary mixers,

(b) Measuring centrifugal force or rotation speed of the concrete mixer tank of the tmck or the stationary mixer with a tachometer or a revolutions-per-minute (RPM) gauge installed on the truck or on any of said stationary mixers; and

(c) Analysing the results of Steps (a) and (b) using the computing unit, combining said results with the results obtained in Step (2) of said method, and further using the combined results in Step (3) of the method to obtain readable and displayable information on the physical properties and workability of the RMC or precast concrete in the concrete mixer of the truck or in any of said stationary mixers.

[0013] In a particular embodiment, the action required on the user’s side upon receiving the alert to the user’s interface is to add water, a chemical dispersant or a chemical admixture containing said dispersant, in an amount calculated by the computing unit to the RMC or precast concrete to maintain the desired physical properties and workability of the RMC or precast concrete. In another particular embodiment, said action required on the user’s side upon receiving the alert to the user’s interface is to adjust or modify slump levels (or workability) of the RMC or pre-cast concrete in a concrete plant or in a concrete mixer by adding water, a chemical dispersant or a chemical admixture containing the dispersant, in an amount calculated by the system, to the RMC or precast concrete to maintain the desired physical properties and workability of the RMC or precast concrete, and further performing a re-inspection. The user may be alerted upon receipt of the displayable information (images) about the decrease in the quality of the aggregates and the change in the composition of the RMC or precast concrete.

[0014] In a certain embodiment, the physical properties and workability of said RMC or said precast concrete are selected from slump levels (workability), consistency, segregation, water bleeding, porosity, density, concrete height, size and shape of aggregates inside the RMC or precast concrete, homogeneity and colour. The slump level of the RMC or precast concrete is correlated with an amount of water to add to the RMC or precast concrete for the preparation of the RMC or precast concrete having the desired consistency and homogeneity. Alternatively, the slump level of the RMC or precast concrete is correlated with an amount of a chemical dispersant or a chemical admixture containing said dispersant to add to the RMC or precast concrete, to disperse said RMC or precast concrete and thus increase the slump level of the RMC or precast concrete to the desired slump level, without adding water. Non-limiting examples of the chemical dispersant are a polycarboxylate polymer or naphthalene sulphonate.

[0015] In still another embodiment, the imaging or video camera and computing unit are manually or remotely operated by a process operator, constmction contractor, truck driver or construction site operator. Alternatively, the imaging or video camera and computing unit are autonomous and configured to be used in the automatic manufacture of the concrete in the concrete plant, without external control or intervention. An exemplary imaging camera is a FLIR thermal imaging camera. [0016] In some embodiments, the communication module is a wired or wireless connection module used a standalone device or integrated in the computing unit or in the external memory. The wireless communication module may be selected from a short-range Bluetooth® or NFC providing wireless communication between the computing unit and the user’s interface for up to 20 m, a Wi-Fi providing the medium-range connection with a network for up to 200 nm, and a GSM allowing the worldwide communication to a cloud. The external memory or user’s interface is selected from a desktop computer, server, remote storage, internet storage, cloud and any mobile device or gadget, such as a smartphone or smart watch.

[0017] The present invention further relates to the visual monitoring and quality control system for continuous visual monitoring and quality control of the aggregates and sand used in preparation of a ready-mix concrete (RMC) or precast concrete, or for continuous visual monitoring and quality control of said RMC or said precast concrete prepared from said aggregates and sand. This system comprises: a) An imaging or video camera for taking images or video of the aggregates and sand, RMC or precast concrete in a quarry, concrete plant, construction site or inside the concrete mixer tank, or an external camera for visual monitoring of the RMC or precast concrete quality outside the concrete mixer tank, b) A computing unit for performing image or video processing, decoding of the images or video received from the imaging or video camera and performing a computational analysis to assess the mechanical and physical properties of the aggregates and sand, or physical properties and workability (slump level) of the RMC or precast, and c) A communication module configured to receive the readable and displayable information on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of the RMC or precast concrete from the computing unit and transmitting said readable or displayable information to an external memory or user’s interface in a form of text, graphics or sound signals, thereby updating the user or alerting the user if any action on the user’s side is required.

[0018] In some embodiments, the visual monitoring and quality control system of the present invention further comprising: a) A hydraulic pressure gauge for indicating the pressure of the RMC or precast concrete inside a concrete mixer tank; and b) A tachometer or a revolutions-per -minute (RPM) gauge for measuring centrifugal force or rotation speed of the concrete mixer tank.

[0019] In certain embodiments, the visual monitoring and quality control system of the present invention may be operated manually or remotely. The system may be placed in a quarry to control and monitor the quality of aggregates and sand collected for the production of concrete. Alternatively, the system may be incorporated into a stationary concrete mixer placed in the concrete plant to perform a control and monitoring of the manufacturing process of concrete by estimating the slump level of the concrete and thus, indicating the amount of water to add to the concrete mix for the preparation of the concrete, and testing homogeneity of the prepared concrete. The system may be autonomous and designed to be used in the automatic manufacture of the concrete in the concrete plant, without external control or intervention.

[0020] In particular embodiments, the system of the present invention is incorporated into a mobile concrete mixer of a concrete truck that transports the RMC or precast concrete from a concrete plant to a construction site. This system is further comprising a container containing a chemical dispersant that disperses the concrete mixture and thus maintains the desired slump level of the concrete.

[0021] In a specific embodiment, the visual monitoring and quality control system of the present invention incorporated into a mobile concrete mixer of a concrete truck, comprising: a) A hydraulic pressure gauge installed inside the concrete mixer tank of the truck, for indicating the pressure of the RMC or precast concrete and additional simulation of the slump level, b) A tachometer or a revolutions-per-minute (RPM) gauge installed on the truck for indicating centrifugal force or rotation speed and tracking progress of the concrete mixer tank of the truck and additional simulation of the slump level, c) An imaging or video camera (100) for taking images and/or video of the RMC or precast concrete inside the concrete mixer tank of the truck during transportation and discharge through a mixer trough at the construction site, or an external camera for concrete quality visual monitoring outside the mixer truck, d) A computing unit (200) for performing image or video processing, decoding and computational analysis for the RMC or precast concrete to assess the slump and homogeneity of the concrete and the presence of aggregates in the concrete mixture, e) A communication module installed into the computing unit (200) and configured to receive images or video signals from the imaging or video camera onto the computing unit and transmit readable information to an external memory or user’s interface in a form of text, graphics or sound signals updating the user or alerting the user if any action on the user’s side is required, and f) A container (300) installed on the truck and containing a chemical dispersant that disperses the concrete mixture and thus maintains the desired slump level of the concrete.

[0022] The above system incorporated into a mobile concrete mixer of a concrete truck is designed to determine a slump level reduction and an amount of a concrete admixture required to maintain the desired slump level, said concrete admixture is added for increasing the slump level to the desired level without adding water to the concrete. This system is also designed to determine a volume of the concrete left in the concrete mixer tank of the truck by calculating an estimated volume discharged (unloaded) by the number of the discharge rounds of said truck.

[0023] The quality control system of the present invention thus allows controlling, image analysing and visual monitoring of the aggregate and sand processing and properties and workability (slump) of fresh concrete and concrete mixes, which is manufactured from these aggregates, sand and then transported to construction sites and used there for construction purposes. The system of the present invention comprises visual monitoring devices, stationary or mobile, installed or remotely used at quarries, concrete plants, in concrete trucks and at the construction sites. The method for continuous visual monitoring of the aggregates, sand and concrete is based on image or video processing and analysis of the aggregates and sand, concrete, concrete mixes or precast concrete, the concrete slump levels, segregation and bleeding, homogeneity of the mixture and consistency. [0024] Various embodiments may allow various benefits and may be used in conjunction with various applications. The details of one or more embodiments are set forth in the accompanying figures and the description below. Other features, objects and advantages of the described techniques will be apparent from the description and drawings and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Disclosed embodiments will be understood and appreciated more fully from the following detailed description taken in conjunction with the appended figures. The drawings included and described herein are schematic and are not limiting the scope of the disclosure. It is also noted that in the drawings, the size of some elements may be exaggerated and, therefore, not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the disclosure.

[0026] Fig. 1 shows crushing rocks into aggregates of various sizes in the quarry.

[0027] Fig. 2 shows the transport of the aggregates and conveyors of the aggregates of different sizes.

[0028] Fig. 3 shows a picture of a yard of aggregates in a concrete plant.

[0029] Fig. 4 shows the transport of aggregates on the conveyor belt at the concrete plant.

[0030] Fig. 5 shows aggregates of different sizes used for the production of concrete mixtures.

[0031] Fig. 6 shows using a set of sieves to examine and control the size of the aggregates.

[0032] Fig. 7 shows a 9 to 14 mm size aggregate soiled (contaminated) with a fine powder used in a concrete plant and caused a failure in the quality of the concrete

[0033] Fig. 8 shows presence of brown clay blocks in the aggregates intended for concrete production.

[0034] Fig. 9 show an image of a slump test of concrete.

[0035] Fig. 10 shows images of the low-slump (dry) concrete discharged at the construction site and having a much lower slump level than required.

[0036] Fig. 11 shows an image of concrete provided with a suitable slump after water was added to the concrete directly at the construction site.

[0037] Fig. 12 shows, on the left, three types of different concrete mixed in a concrete mixer, and, on the right, three corresponding images of the slump level of the concrete as tested.

[0038] Fig. 13 shows concrete that has not been mixed enough and therefore lumps can be seen in the concrete. [0039] Fig. 14 shows an image of decomposed concrete having a collapsed slump and a lot of water bleeding.

[0040] Fig. 15 shows an image of shows an image of an incorrect grading of aggregates in the concrete having a high slump and therefore a concrete mixture with segregation.

[0041] Fig. 16 shows segregation of the hardened concrete in the wall, in one of the newly built structures.

[0042] Fig. 17 shows the control and visual monitoring system of the present invention installed on a concrete truck.

[0043] Figs. 18a, 18c and 18e show the images of the aggregates having different sizes, recorded with a camera.

[0044] Figs. 18b, 18d and 18f show the corresponding images processed in the computing unit using a filter that marks the boundaries of the aggregates. That allows the computing unit to calculate the size distribution of the aggregates.

[0045] Fig. 19 shows the detection of contaminants in aggregates by detecting the changes in the hue shades of the image (indicated by the red dots in the image).

[0046] Figs. 20a, 20c, 20e, 20g, 20i, 20k, 20m and 20o show the images of the ready-mix concrete or precast concrete having different grades, which indicate different physical properties (consistency, segregation and homogeneity) and different workability (slump level) of the concrete.

[0047] Figs. 20b, 20d, 20f, 20h, 20j, 201, 20n and 20p show the corresponding images processed in the computing unit for each and every grade using the filter that identifies the shade contours of the images using the image pixels hue levels. That gives an indication of the levels of consistency and homogeneity (fluidity) and slump of the concrete by correlating these measured levels to the level of consistency, homogeneity and slump determined by the relevant standard.

DETAILED DESCRIPTION

[0048] In the following description, various aspects of the present application will be described. For purposes of explanation, specific details are set forth in order to provide a thorough understanding of the present application. However, it will also be apparent to one skilled in the art that the present application may be practiced without the specific details presented herein. Furthermore, well-known features may be omitted or simplified in order not to obscure the present application.

[0049] The term "comprising", used in the claims, is "open ended" and means the elements recited, or their equivalent in structure or function, plus any other element or elements which are not recited. It should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a composition comprising x and z" should not be limited to compositions consisting only of components x and z. Also, the scope of the expression "a method comprising the steps x and z" should not be limited to methods consisting only of these steps.

[0050] Unless specifically stated, as used herein, the term "about" is understood as within a range of normal tolerance in the art, for example within two standard deviations of the mean. In one embodiment, the term "about" means within 10% of the reported numerical value of the number with which it is being used, preferably within 5% of the reported numerical value. For example, the term "about" can be immediately understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. In other embodiments, the term "about" can mean a higher tolerance of variation depending on for instance the experimental technique used. Said variations of a specified value are understood by the skilled person and are within the context of the present invention. As an illustration, a numerical range of "about 1 to about 5" should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges, for example from 1-3, from 2-4, and from 3-5, as well as 1, 2, 3, 4, 5, or 6, individually. This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Unless otherwise clear from context, all numerical values provided herein are modified by the term "about". Other similar terms, such as "substantially", "generally", "up to" and the like are to be construed as modifying a term or value such that it is not an absolute. Such terms will be defined by the circumstances and the terms that they modify as those terms are understood by those of skilled in the art. This includes, at very least, the degree of expected experimental error, technical error and instrumental error for a given experiment, technique or an instrument used to measure a value.

[0051] As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.

[0052] Manufacturing of concrete and concrete mixes start at quarries, where aggregates and sand of different sizes are produced and processed. Fig. 1 shows crushing rocks into aggregates of various sizes in the quarry. After the crushing process, the aggregates are separated by a set of sieves and stacked in different piles according to the different sizes. Fig. 2 shows the transport of the aggregates and conveyors of the aggregates of different sizes. The aggregates and sand are transported to the concrete plant for the purpose of producing the concrete. The concrete plant uses four to five types of aggregates and sand to produce concrete mixtures, usually having particle size of 25 mm and below. Fig. 3 shows a picture of a yard of aggregates and sand in a concrete plant.

[0053] From that yard in the concrete plant, the aggregates are transferred on top of the aggregate conveyor to the concrete mixer, to allow production of the concrete by mixing the aggregates and sand, cement, water, additives, and chemical admixtures to produce a homogeneous concrete mixture. Fig. 4 shows the transport of aggregates on the conveyor belt. The aggregates and sand are transported from a quarry and differ from each other mainly in their size. Fig. 5 shows aggregates of different sizes used for the production of concrete mixtures. Examination of the size of the aggregates is performed in a laboratory by filtering an aggregate sample using a set of sieves, as seen in Fig. 6. [0054] Because it is a natural material that is crushed, the aggregates come in several sizes and are often soiled with dust and other contaminants/impurities that affect the quality of the concrete. Using a quality control and monitoring system of the present invention, which is a computerised system that performs photography and analysis of the size of the aggregates in the pile, allows to control the quality of the aggregates in the quarry as well as to visually monitor the aggregates and sand supplied to the concrete plant. The system will provide a user with information on the properties of the aggregates and sand, moisture and contaminants in the aggregates and sand, and alert the user in case of an excessive aggregate size split or the presence of contaminants or dust content that exceeds the allowable amount and also an examination of excess moisture of aggregates and sand (on rainy days). Fig. 7 shows a 9 to 14 mm size aggregate soiled with a fine powder used in a concrete plant and caused a failure in the quality of the concrete. Fig. 8 shows the presence of brown clay blocks in the aggregates. Clay blocks severely impair the quality of the concrete.

[0055] The present invention relates to a quality control system and method for continuous visual monitoring of physical properties and workability of concrete, starting from its manufacturing from aggregates and sand, for which monitoring of their size, particle size distribution, colour, moisture (wetness in rainy days) and purity (low content of contaminants) is important, continuing with transportation of concrete and until all the concrete volume from the truck is discharged (unloaded) completely in a construction site.

[0056] The quality control system of the present invention allows controlling and visual monitoring of the aggregate and sand processing and physical properties and workability (slump) of concrete, which is manufactured from the aggregates and sand and then transported to construction sites and used there for construction purposes. The system of the present invention comprises visual monitoring devices, stationary or mobile, installed or remotely used at quarries, concrete plants, in concrete trucks and at the construction sites. The method for continuous visual monitoring of the aggregates, sand and concrete is based on image or video processing and analysis of the aggregates and sand, fresh concrete, concrete mixes or precast concrete, the concrete slump levels, physical properties and consistency of the concrete. The method of the present invention also comprises image analysis and hydraulic pressure monitoring of the ready-mix concrete (RMC) in a concrete truck, concrete mixer or in a transportation or storage device of concrete, by the concrete manufacturer and/or by the concrete user. [0057] In the present application, the terms “concrete”, “precast concrete” and “RMC” (ready-mix concrete) are considered equivalent and used therefore interchangeably. In general, concrete is a material produced from a combination of aggregates of different sizes, sand, cement, water, additives, and chemical additives. The concrete is produced in the concrete plant and transported to the construction site using the concrete load (imported concrete). The main properties of concrete are:

1) Mechanical strength, in particular compressive strength. The strength of normal concrete varies between 20 and 40 MPa. The term “high performance concrete” is used above 50 MPa, which corresponds to a force of 50 tonnes acting on a square with sides of ten centimetres. Mechanical strength depends mainly on the amount of water in concrete.

2) Porosity and density. The denser (or the less porous) the concrete the better its performance and the greater its durability. The density of concrete is increased by optimising the dimensions and packing of the aggregate and reducing the water content.

3) Homogeneity of a concrete mixture, consistency, and fluidity (without lumps, segregation or water bleeding).

[0058] “Slump” or “slump level” is the measure of concrete homogeneity, consistency and fluidity during the condition of the fresh concrete. It shows the flow and overall workability of freshly mixed concrete. Concrete workability refers to how easily freshly mixed concrete can be placed, consolidated and finished with minimal loss of homogeneity. In general, the workability of concrete is determined by how fluid the concrete mix is (i.e., the cement to water ratio), which is essentially the slump of concrete. The more fluid the concrete, the higher the slump, and whilst the slump is seen as a measure of water content, it is typically also used as a measure of concrete consistency. Simply put, the higher the slump, the wetter the mix. Five-inch slump is very common with normal weight concrete and is a good for pumping. Slumps that are above average will cause reduced strength, durability, and permeability of the concrete, if more water added to increase the slump level. Unless otherwise defined, “concrete consistency” in the present invention refers to relative mobility or ability of freshly mixed concrete to flow. It includes the entire range of fluidity from the driest to the wettest possible mixtures.

[0059] There are three primary factors that affect the workability of concrete:

1) The ratio of water to cement. The higher proportion of cement (or lower water to cement ratio) typically means a stronger concrete mix. With the right amount of cement paste, the coating of aggregates delivers a better consolidation and finish. If the mix is not hydrated adequately, the mechanical strength will be low. It is also a lot harder to place and finish. However, if too much water is used then this can lead to a negative impact on segregation and final mechanical strength, which is detrimental to the build. Typically, most mixes look to get a ratio of around 0.45 to 0.6 to achieve workable concrete.

2) The size and shape of aggregates (stones and sand) used in a concrete mix, and contaminates and moisture in the aggregates and sand, affect its workability. As aggregate surface area increases, the more cement paste is needed to cover the entire surface of aggregates and the increased water demand. So, concrete mixes with smaller aggregates will be typically less workable when compared to larger sizes. Crushed aggregates with decent proportions tend to bond best with the cement and deliver decent workability.

3) Chemical admixtures are used in concrete to improve things like mechanical strength and workability and handling of the concrete mix. A few examples include plasticisers to help regulate concrete consistency, air entrainers (which are mostly surface-active substances, such as soaps from natural resins or synthetic non-ionic and ionic tensides with defoaming agents, that are used to entrain microscopic air bubbles into the concrete and protect it from frost) to improve freeze/thaw resistance and internal curing to help reduce damage such as cracks and strength loss.

[0060] As used herein, the term “concrete admixture” includes manufactured chemical admixtures added during concrete mixing to enhance or to adjust the workability (slump) of the fresh concrete. Concrete admixtures are added to concrete batch immediately before or during mixing concrete. They improve concrete quality, manageability, acceleration, or retardation of setting time, among other properties that could be altered to get specific results. Many, not to say all, concrete mixes today contain one or more concrete admixtures that helps pouring the ready-mix concrete (RMC) or precast concrete and driving down cost while increasing productivity.

[0061] The slump test is used to measure the workability and assess the consistency of fresh concrete. Generally, it is used to check that the correct volume of water has been added to the mix. Workability of concrete is determined by checking the slump level of concrete using a cone as shown in Fig. 9. The slump test of concrete includes the following steps:

1) The cone is positioned on the base plate with the smaller aperture uppermost.

2) Freshly supplied concrete is poured into the cone to roughly one third of its depth (100 ml).

3) The concrete is tamped using 25 strokes of the steel rod.

4) Further concrete is added to fill the cone to about two thirds depth (another 100 mm of concrete).

5) The concrete is tamped again using 25 strokes of the rod just penetrating the layer below.

6) The cone is filled to the top and tamped using a final 25 strokes with the steel rod.

7) Using the tamping rod slid across top of the cone the surface of the concrete is “struck off’ level with the top of the cone.

8) The cone is carefully lifted upwards, clear of the concrete and placed, upside-down beside the concrete.

9) After about a minute, the unrestrained concrete will settle downwards or “slump” due to gravity.

10) The steel rod is used to span the inverted cone and towards the slumped concrete.

11) The height difference between the steel cone and the slumped concrete is measured. This difference, which is measured to the nearest 10 millimetres, is actually the slump level.

[0062] Slump test results can be classified in four types:

1) True slump, which is the only slump that can be measured in the test according to standards. The measurement is taken between the top of the cone and the top of the concrete once the cone has been removed.

2) Zero slump, which is the indication of a very low water to cement ratio that results in dry mixes. This type of concrete is largely used for road construction.

3) Collapsed slump, which indicates that the water to cement ratio is too high, for example, the concrete mix is too wet, or it is a high workability mix. 4) Shear slump, which indicates an incomplete result, and the concrete needs to be retested.

[0063] Customers and buyers of concrete usually order a certain mechanical strength and slump level of concrete. Concrete plants produce concrete and supplies it to the customers. The slump level of concrete decreases from the moment the concrete is prepared due to hydration of cement in the concrete with water, water absorption by aggregates in the concrete, change of ambient temperature, impurities such as clays and organic materials in the aggregates and sand used to make the concrete. Therefore, the slump level of concrete indicating its homogeneity, consistency and fluidity decreases with the time of transportation of the concrete from the concrete plant until the concrete truck arrives at the construction site and the concrete is used. Fig. 10 shows images of the zero-slump (dry) concrete discharged at the construction site and having a much lower slump level than required. Fig. 11 shows an image of concrete provided with a suitable slump after water was added to the concrete directly at the construction site, which reduced its mechanical strength.

[0064] After the concrete has been produced by an operator in a concrete plant with a certain slump, it is possible, using image analysis, to determine the concrete slump and the concrete slump reduction in the concrete plant right after the mixing all the concrete components and during the transportation of the concrete or the RMC or precast concrete and during the discharge (unload) of the concrete at the construction site. The slump level and the other properties of the fresh concrete can be assessed by image processing and finding a correlation between the image of the concrete fluidity and the slump test performed as described above. Fig. 12 shows on the left, three types of different concrete mixed in a concrete mixer, and, on the right, three corresponding images of the slump level of the concrete as tested. The difference in the slump level of the concrete can be clearly seen just by looking at these images of the concrete.

[0065] Apart from the slump level of concrete, the quality of concrete is affected by a number of factors. Fig. 13 shows concrete that has not been mixed enough and therefore lumps can be seen in the concrete. These lumps will be poured into a building structure and will substantially worsen the properties of the hardened concrete in the structure, which will eventually deteriorate because of these lumps.

[0066] Fig. 14 shows an image of decomposed concrete having a collapsed slump and a lot of water bleeding and segregation. Fig. 15 shows an image of an incorrect grading of aggregates in the concrete and therefore a concrete mixture with segregation (separations of the concrete components) can be seen. Examples of these failures in concrete preparation essentially impair the durability and quality of the concrete (significantly reduced mechanical strength, water permeability into the structure, corrosion of the iron bars, etc.). Fig. 16 shows segregation of the hardened concrete in the wall, in one of the newly built structures.

[0067] As mentioned above, the present application describes a control and monitoring system for the properties of fresh concrete by assessing its slump level and homogeneity using image processing and identifying the reasons of the concrete failure while it is still being produced in the concrete plant, transporting the concrete in the concrete truck to the construction site and at the time of discharging the concrete into the building structure or pump. A camera located on top of the concrete preparation system in the concrete plant or on the concrete truck that transports the concrete to the construction site or even as a mobile system in the hands of the contractor who receives the prepared concrete. This system allows an image of the concrete to be obtained at any given time and makes it possible, by processing the image, to assess the slump level of the concrete at any given moment and without checking by an operator or quality controller at the plant or at the building site, or to detect conditions of defective concrete preparation and improper handling of the concrete mixes containing non- homogeneous concrete, lumps, water bleeding, segregation of aggregates, the slump level too high or too low, and the like.

[0068] The control and monitoring system of the present invention is installed in the concrete plant or\and on top of the concrete truck that transports the concrete to the construction sites and in the construction site. It constantly examines the concrete slump and homogeneity, monitors the decrease of fluidity of the concrete as a function of time and correlates it to the slump level ordered by the contractor.

[0069] A container with a concrete chemical admixture installed on top of the truck is capable of increasing or adjusting the slump level, while delivering the concrete or discharge the concrete at the building site. The adjustment of the slump level is enabled by several steps: (1) simulating the slump level and identifying between the actual slump and the desired slump level at any time, and (2) adjustment of the slump level using chemical admixture (not water) by a control system using image analysis or video recording, which can be continuously broadcasted by a truck driver or by a stationary mixer operator at constructions sites to the control centre or unit of a concrete plant. At the control centre (unit), visual monitoring of concrete and analysis of the concrete properties are performed using an automatic computerised control system.

[0070] Using a closed control circuit that receives slump data and slump decrease at any time, it is possible to fix the concrete mixture fluidity and homogeneity by adding a suitable chemical admixture (dispersant) to ensure concrete supply at the desired slump level and without uncontrolled addition of water at the construction site. This will impart much better control of the quality of the concrete. [0071] In one aspect of the present invention, a method for continuous visual monitoring and quality control of: 1) aggregates and sand produced in a quarry and used in the preparation of ready- mix concrete (RMC) or precast concrete, or 2) specified RMC or specified precast concrete prepared from specified aggregates and sand, said method comprising the following steps:

( 1) Obtaining a visual information on mechanical and physical properties of said aggregates and sand, or physical properties and workability of said RMC or said precast concrete, with an imaging or video camera of a visual monitoring and quality control system,

(2) Processing, decoding and performing computational analysis of the visual information obtained in Step (1), with a computing unit of said visual monitoring and quality control system, to obtain results on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of the RMC or precast concrete,

(3) Analysing and correlating the results of Steps (2) using said computing unit to obtain readable and display able information on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of said RMC or said precast concrete, and

(4) Transmitting said readable or displayable information obtained in Step (3) using a communication module of said visual monitoring and quality control system to an external memory or user’s interface in a form of text, graphics or sound signals, thereby updating the user or alerting the user if any action on the user’ s side is required.

[0072] In one embodiment, the imaging or video camera, computing unit and communication module of the visual monitoring and quality control system are installed in the quarry or at the production facility of the aggregates and sand to perform said method on the aggregates and sand produced in the quarry, to control and monitor the quality of aggregates and sand used for the production of the fresh RMC or precast concrete. The mechanical and physical properties of the aggregates and sand are selected from a particle size and particle size distribution of the aggregates and sand, colour of the aggregates, wetness (amount of moisture in rainy days) of the aggregates and sand, and purity (low content of contaminants) of the aggregates and sand.

[0073] In another embodiment, the imaging or video camera, computing unit and communication module of the visual monitoring and quality control system are incorporated into a stationary concrete mixer placed in a concrete plant to perform said method on the RMC or precast concrete, to visually monitor the manufacturing process of the RMC or precast concrete and to control the quality of the produced RMC or precast concrete.

[0074] In a further embodiment, the imaging or video camera, computing unit and communication module of the visual monitoring and quality control system are incorporated into a mobile concrete mixer of a concrete truck that transports said RMC or precast concrete from a concrete plant to a construction site, to perform said method on the RMC or precast concrete during the transportation and discharge of the RMC or precast concrete at the construction site. In this case, the information received from the system is a total volume of the RMC or precast concrete left in the concrete mixer tank of the truck, and it is calculated by the computing unit from an estimated volume discharged (unloaded) by the number of the discharge rounds of the truck.

[0075] In yet further embodiment, the imaging/video camera, computing unit and communication module of the visual monitoring and quality control system are incorporated into a stationary concrete mixer placed at a construction site to perform said method on the RMC or precast concrete, to control the quality of the RMC or precast concrete obtained from a concrete plant or manufacturer.

[0076] In some embodiments, the method of the present invention may further comprise:

(a) Measuring a hydraulic pressure of the RMC or precast concrete inside the stationary mixer, or inside the concrete mixer tank of the truck transporting said RMC or precast concrete from the concrete plant to the construction site, or inside the stationary mixer installed at the constructions site, with a hydraulic pressure gauge installed on the truck or on any of said stationary mixers,

(b) Measuring centrifugal force or rotation speed of the concrete mixer tank of the tmck or the stationary mixer with a tachometer or a revolutions-per-minute (RPM) gauge installed on the truck or on any of said stationary mixers, and

(c) Analysing the results of Steps (a) and (b) using the computing unit, combining said results with the results obtained in Step (2) of said method of the present invention, and further using these combined results in Step (3) of the method to obtain readable and displayable information on the physical properties and workability of the RMC or precast concrete in the concrete mixer of the truck or in any of said stationary mixers.

[0077] In a particular embodiment, the action required on the user’s side upon receiving the alert from the system is to add water, a chemical dispersant or a chemical admixture containing said dispersant to the RMC or precast concrete in an amount calculated by the system so to maintain the desired physical properties and workability of the RMC or precast concrete. [0078] In the present application, the terms “tachometer” and “RPM gauge” are considered entirely equivalent and used therefore interchangeably. In general, the RPM gauge or tachometer is a device measuring the centrifugal force or rotational speed of a shaft or disk, as in a motor or other machine. In the concrete mixer truck, the RPM gauge measures the centrifugal force or rotational speed of the concrete mixer tank of the truck. This device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common and also can be used to indicate mixing or unloading of the concrete and to evaluate the volume remaining in the mixing tank.

[0079] The hydraulic pressure gauges and RPM gauges installed on the truck allow an additional indication to simulate the slump level. The control system of the present invention determines the slump level and the slump reduction and an amount of the concrete admixture, which should be added in order to increase and adjust the slump level to the desired level without adding water to the concrete. In addition, the control system determines the volume of concrete left in the concrete tank by calculating the estimated volume discharged (unloaded) by the number of the discharge rounds. [0080] In a further aspect of the present invention, the visual monitoring and quality control system used in the method of the present invention for continuous visual monitoring and quality control of the aggregates and sand used in preparation of a ready -mix concrete (RMC) or precast concrete, or for continuous visual monitoring and quality control of said RMC or said precast concrete prepared from said aggregates and sand, comprises: a) An imaging or video camera for taking images or video of the aggregates, sand, RMC or precast concrete in a quarry, concrete plant, construction site or inside the concrete mixer tank, or an external camera for visual monitoring of the RMC or precast concrete quality outside the concrete mixer tank, b) A computing unit for performing image or video processing, decoding of the images or video received from the imaging or video camera and performing a computational analysis to assess the mechanical and physical properties of the aggregates and sand, or physical properties and workability (slump level) of the RMC or precast, and c) A communication module configured to receive the readable and displayable information on the mechanical and physical properties of the aggregates and sand, or the physical properties and workability of the RMC or precast concrete from the computing unit and transmitting said readable or displayable information to an external memory or user’s interface in a form of text, graphics or sound signals, thereby updating the user or alerting the user if any action on the user’s side is required. [0081] The visual monitoring and quality control system of the present invention may further comprise: a) A hydraulic pressure gauge for indicating the pressure of the RMC or precast concrete inside a concrete mixer tank, and b) A tachometer or a revolutions-per -minute (RPM) gauge for measuring centrifugal force or rotation speed of the concrete mixer tank.

[0082] The visual monitoring and quality control of the present invention can also be a manual quality control system used by a construction contractor to perform quality control of the concrete obtained from the concrete manufacturer. The construction contractor receives the concrete mix and wants a simple, fast method and complete documentation, to make sure he/she gets a homogeneous concrete mix with the proper slump level at the construction site. With the help of the system of the present invention, the contractor will receive homogeneous concrete having the required slump level outside/away from or within the construction site.

[0083] As mentioned above, the system of the present invention can be placed in the quarry or at the production facility of the aggregates and sand to:

1) Obtain a visual information with the imaging or video camera of the system of the present invention on the physical properties of aggregates and sand produced at a quarry, said aggregate physical properties are selected from the particle size of the aggregates and sand, aggregate and sand particle size distribution, colour, moisture (wetness in rainy days) and purity (low content of contaminants),

2) Process, decode and perform computational analysis of the visual information on the physical properties of the aggregates produced in the quarry, using the computing unit of the system of the present invention, and

3) Transmit the readable information from the computing unit to an external memory or user’s interface in a form of text, graphics or sound signals updating the user or alerting the user if any action on the user’s side regarding the size, moisture (wetness in rainy days) and purity (low content of contaminants) of the aggregates and sand is required.

[0084] In other embodiments, the system of the present invention can also be placed in the concrete plant or construction site to perform a control and monitoring of the production process of concrete by estimating the slump level of the concrete and thus, indicating the correct amount of water to add to the concrete mixture for the preparation of the fresh concrete, and testing homogeneity of the prepared concrete. That is, the system can actually be an autonomous system for the production of concrete in the concrete plant and at the construction site, without the need for human intervention or dependence on the concrete loader responsible for the production of the concrete.

[0085] Thus, the control and monitoring system of the present invention can be installed in any of the following applications:

1) In a quarry, to control and monitor the quality of aggregates and sand used for the production of concrete,

2) In a concrete plant that produces the concrete in a mixer preparing and mixing the concrete mixes,

3) In the truck that transports the prepared concrete to the construction site, and

4) As a manual control device for the contractor (user) who receives and uses the prepared concrete. [0086] The imaging or video camera providing the image analysis and an up-to-date picture for continuous examination of the concrete in the concrete truck and/or in the concrete plant and/or in the entire work area at the construction sites that use the concrete that was produced from the RMC in the concrete mixer tank of the truck allows visual monitoring and controlling of the RMC during the following several stages of the concrete mixer truck operation:

(1) Transportation of the concrete in the truck,

(2) Discharge (unload) of the concrete from the truck, and

(3) Supervision on the laboratories that test the concrete, and construction workers who handle the concrete.

[0087] In some embodiments, the system of the present invention further comprises a container containing a chemical admixture (dispersant) that disperses/dilutes the concrete mixture. Non-limiting examples of the dispersants suitable for use in the present invention are polycarboxylate polymer and naphthalene sulphonate.

[0088] Fig. 17 shows the control and visual monitoring system of the present invention installed on a concrete truck. The following components of the system are shown in the figure:

100 - Camera (static images or video) for imaging the concrete mix inside the mixer and while discharging it in the mixer trough.

200 - Computing unit for performing image or video processing and decoding, and for transmitting images to the user’s interface of a truck driver, or system operator, or contractor at the construction site, or to a control centre in the concrete plant.

300 - Container containing a chemical admixture (dispersant) that disperses the concrete mixture. [0089] There are several imaging devices and cameras that can be used in the system of the present invention. An exemplary imaging device is described in the KR 101309850 B 1 patent, which discloses a device for inspecting images of residues inside a ready-mixed concrete mixer truck agitator drum and an image inspection system using the same, generating photograph images at high definition, while lighting the inside of the concrete mixer with a light source of high brightness, thereby enabling accurate inspection.

[0090] Another exemplary imaging camera that can be used in the system of the present invention is a FLIR thermal imaging camera, which is capable of monitoring the consistency of the ready-mix concrete. This type of cameras does not “see” water in the ready-mix concrete, but rather visualises the impact water has on the temperature of surfaces around them due to the evaporation process. [0091] In some embodiments, the communication module configured to receive images or video signals from the imaging or video camera onto the computing unit and transmit readable information to an external memory or user’ s interface in a form of text, graphics or sound signals updating the user or alerting the user if any action on the user’s side is required, is the wired or wireless connection module. In case of the wireless connection module, it can be either Bluetooth ^® or NFC providing the short-range wireless communication between the computing unit and the external memory or the user’s interface for up to 20 m. If this module is Wi-Fi, the connection can be established with a network for up to 200 nm, while GSM allows the worldwide communication to a cloud. The external memory or user’s interface may be any mobile device or gadget, such as a smartphone or smart watch. It may also be a desktop computer, server, remote storage, internet storage or cloud.

[0092] The system of the present invention allows:

(1) Improved quality control of aggregates and sand produced in a quarry or at the production facility of the aggregates and sand.

(2) Reduction of cement additions due to uncontrolled concrete damage.

(3) Supervision and control of operations at the constmction sites.

(4) Cost reduction of expensive chemical admixtures adding to the concrete in the plant.

(5) Production of concrete in a lower slump and increasing it before the concrete discharge (unload). This results in savings in an additional concrete cost.

(6) Working with lower-quality and lower-cost aggregates.

(7) Development of the system of the present invention for contractors' companies to simulate and control the concrete delivered by the concrete companies.

(8) Continuous monitoring of the concrete quality and controlling the concrete properties in addition to the slump levels. Such as segregation and water bleeding.

(9) Improved quality control of the produced concrete. (10) Prevention of manual intervention in the concrete at the site by the driver or any other person.

(11) Change the composition of aggregate mixtures in the production of concrete depending on the quality of the aggregates and sand obtained.

[0093] The control and monitoring system of the present invention has a number of notable pros:

1) Avoiding addition of water to the concrete mix at the construction site, in order to disperse the concrete in an uncontrolled manner. That will reduce the number of failures in the mechanical strength of the concrete.

2) Reducing the safety coefficients or the amount of cement in the concrete mixture, thus reducing considerable cost and environmental pollution which is reflected in the low consumption of cement.

3) Ability to control the quality of the concrete by determining the fixed water-to-cement ratio, and further adding a chemical admixture (dispersant) (instead of water) that would allow stability and control of the concrete properties.

4) Control and monitoring of the concrete mixture throughout the entire transportation and at the construction site by the concrete manufacturer wherever the concrete is located and during all time of its transportation and use.

5) Savings in expensive chemical admixture used to maintain the proper slump level.

6) Full control and monitoring of the concrete condition by a concrete manufacturer or building contractor.

[0094] In a further aspect of the present invention, a method for continuous visual monitoring and quality control of aggregates and sand and physical properties and workability of concrete, comprises the following steps:

1) Obtaining a visual information with the imaging or video camera of the system of the present invention on the physical properties of aggregates and sand produced at a quarry, said aggregate physical properties are selected from the particle size of the aggregates and sand, aggregate and sand particle size distribution, colour, moisture (wetness in rainy days) and purity (low content of contaminants),

2) Processing, decoding, and performing computational analysis of the visual information on the physical properties of the aggregates and sand produced at the quarry with the computing unit of the system of the present invention,

3) Transmitting the readable information from the computing unit to an external memory or user’s interface in a form of text, graphics or sound signals updating the user or alerting the user if any action on the user’s side regarding the size, moisture (wetness in rainy days) and purity (low content of contaminants) of the aggregates and sand is expected,

4) Measuring a hydraulic pressure of a ready-mix concrete (RMC) or precast concrete produced from said aggregates and sand in a concrete plant inside a stationary mixer installed at said plant, or inside a concrete mixer tank of a truck transporting said RMC and precast concrete from the concrete plant to a construction site, or inside a stationary mixer installed at the constructions site, with a hydraulic pressure gauge installed on the truck or on the stationary mixer,

5) Measuring centrifugal force or rotation speed of the concrete mixer tank of the tmck or the stationary mixer with a tachometer or a revolutions-per-minute (RPM) gauge installed on the truck or on any of said stationary mixers,

6) Imaging said RMC or precast concrete in the concrete mixer tank of the truck or in any of said stationary mixers using an imaging or video camera installed inside or outside the concrete mixer tank or any of the stationary mixers, and

7) Analysing the results of the steps 4), 5) and 6) using a computing unit, and transmitting and displaying readable information regarding slump levels (workability), consistency, segregation, water bleeding and other properties of the RMC or precast concrete in the concrete mixer of the truck or in any of said stationary mixers.

[0095] In yet further aspect of the present invention, a method for continuous monitoring of slump levels (workability), consistency, segregation, water bleeding and other properties of ready-mix concrete (RMC) or precast concrete in a concrete mixer truck or in any stationary mixer during transportation of said RMC or precast concrete from a concrete plant to a construction site, and during exploitation (processing or handling) of said RMC or precast concrete in the construction site, said method comprising the following steps:

1) Measuring a hydraulic pressure of the RMC or precast concrete in the concrete plant inside a stationary mixer installed at said plant, or inside a concrete mixer tank of a tmck transporting said RMC or precast concrete from the concrete plant to the construction site, or inside a stationary mixer installed at the constmctions site, with a hydraulic pressure gauge installed on the tmck or on the stationary mixer,

2) Measuring centrifugal force or rotation speed of the concrete mixer tank of the tmck or the stationary mixer with a tachometer or a revolutions-per-minute (RPM) gauge installed on the truck or on any of said stationary mixers, 3) Imaging said RMC or precast concrete in the concrete mixer tank of the truck or in any of said stationary mixers using an imaging or video camera installed inside or outside the concrete mixer tank or any of the stationary mixers, and

4) Analysing the results of the steps 1), 2) and 3) using a computing unit, and transmitting and displaying readable information regarding slump levels (workability), consistency, segregation, water bleeding and other properties of the RMC or precast concrete in the concrete mixer of the truck or in any of said stationary mixers.

EXAMPLES

[0096] Figs. 18a, 18c and 18e show the images of the aggregates having different sizes, recorded with a camera, while Figs. 18b, 18d and 18f show the corresponding images processed by the computing unit using a filter that marks the boundaries of the aggregates. This allows the computing unit to calculate the particle size distribution of aggregates, analyse and compare (correlate) the calculated values with the quality of aggregates in the preparation of fresh concrete, ready mix or precast concrete, and also warn the user if the quality of aggregates for concrete preparation is low from the very beginning of the preparation process or deteriorates in the process.

[0097] Fig. 19 shows the detection of contaminants in aggregates by detecting the changes in the hue shades of the image (indicated by the red dots in the image). As mentioned above, moisture and contaminants in the aggregates strongly affect the physical properties and workability of the concrete produced from these aggregates.

[0098] Figs. 20a, 20c, 20e, 20g, 20i, 20k, 20m and 20o show the images of the ready-mix concrete or precast concrete having different grades. The numerical grade of the concrete, ready-mix or precast, seen in these figures is a combined parameter indicating the physical properties of the concrete, such as consistency (fluidity), segregation and homogeneity, and different slump levels. The lower the grade, the more fluid and homogeneous concrete and the higher the slump.

[0099] Figs. 20b, 20d, 20f, 20h, 20j, 201, 20n and 20p show the corresponding images processed by the computing unit for each and every grade using the filter that identifies the shade contours of the images using the image pixels hue levels. That gives an indication of the levels of consistency and homogeneity (fluidity) and slump of the concrete by correlating these measured levels to the level of consistency, homogeneity and slump determined by the relevant standard.