TITLE OF THE INVENTION MONOLITHIC BUILDING BLOCK

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from UK patent application 1513077.6, filed July 24, 2015, which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to monolithic building blocks, and to methods of producing and using such building blocks.

SUMMARY OF THE PRESENT INVENTION

[0003] The present invention relates to a building block including longitudinal zones having a gradient in at least one thermal, physical, and/or mechanical characteristic, and to methods of producing and using such a building block.

[0004] In accordance with an aspect of teachings herein, there is provided a monolithic building block, including: (a) a first aggregate material; and (b) a second aggregate material; the first aggregate material and the second aggregate material embedded within a cementitious matrix to form the monolithic building block; a first cross-sectional slice of the block, taken in a first direction, having a first average density; a second cross-sectional slice of the block, taken in the first direction, having a second average density; the block having at least one of the following structural properties: (1) a differential density between the first and second cross- sectional slices is at least 300 kg/m ; (2) a thermal conductivity of the second cross-sectional slice is at most 0.2 W/(m*K); and (3) a thermal mass ratio of the first and second cross-sectional slices, per unit volume, is at least 2: 1. [0005] In accordance with an aspect of teachings herein, there is provided a monolithic building block, including: (a) a cementitious matrix; (b) a first phase; and (c) a second phase; the first phase including at least a first aggregate material, wherein the at least first aggregate material and the second phase are intimately dispersed within the cementitious matrix to form a cementitious composite material; wherein, in a first cross-sectional slice of the block, taken in a first direction, a first average density of the cementitious composite material is pi; wherein, in a second cross-sectional slice of the block, taken in the first direction, a second average density of the cementitious composite material is p ₂ ; and wherein a differential density (pi - p ₂ ) is at least 300 kg/m ³ .

[0006] In accordance with an aspect of teachings herein, there is provided a building block, including (a) a cementitious matrix; (b) a first phase; and (c) a second phase; the first phase including at least a first aggregate material, the aggregate material and the second phase disposed within the cementitious matrix to form a cementitious composite material within the building block; wherein, in a first cross-sectional slice of the block, taken in a first direction, a first average density of the cementitious composite material is pi; wherein, in a second cross- sectional slice of the block, taken in the first direction, a second average density of the cementitious composite material is p ₂ ; the building block having at least one of the following structural properties: (1) a differential density (pi - p ₂ ) is at least 300 kg/m ; (2) a thermal conductivity of the cementitious composite material in the second cross-sectional slice is at most 0.36 W/(m*K); (3) a thermal mass ratio of the cementitious composite material in the first cross-sectional slice to the cementitious composite material in the second cross-sectional slice, per unit volume, is at least 2:1; (4) a thermal conductivity ratio of a thermal conductivity of the cementitious composite material in the first cross-sectional slice to the thermal conductivity of the cementitious composite material in the second cross-sectional slice is at least 3:1; and (5) a volume fraction ratio of a volume fraction of the second phase in the cementitious composite material in the first cross-sectional slice to a volume fraction of the second phase in the cementitious composite material in the second cross-sectional slice is at least 5: 1, and optionally, at least 7:1, at least 10:1, at least 25: 1, at least 50:1, or at least 100:1.

[0007] A monolithic building block, including: (a) a cementitious matrix; (b) a first phase; and (c) a second phase; the first phase including at least a first aggregate material, the aggregate material and the second phase intimately dispersed within the cementitious matrix to form a cementitious composite material of, or forming, the monolithic building block; wherein, over a length of at least 10cm of the monolithic building block, the monolithic building block exhibits a monotonic or substantially monotonic change in at least one of the following structural properties: (1) density; (2) thermal conductivity; and (3) thermal mass.

[0008] In accordance with an aspect of teachings herein, there is provided a monolithic building block, including: (a) a cementitious matrix; (b) a first phase; and (c) a second phase; the first phase including at least a first aggregate material, the second phase including at least a second aggregate material, wherein the first and second aggregate materials are intimately dispersed within the cementitious matrix to form a cementitious composite material; wherein, in a first cross-sectional slice of the block, taken in a first direction, a first average density of the cementitious composite material is pi; wherein, in a second cross-sectional slice of the block, taken in the first direction, a second average density of the cementitious composite material is p ₂ ; and wherein a differential density (pi - p ₂ ) is at least 300 kg/m .

[0009] In accordance with an aspect of teachings herein, there is provided a method of producing a monolithic building block, the method including: (a) introducing a first aggregate material, a light phase, with respect to the first aggregate material, a cementitious material, and an aqueous liquid, to a vessel, to form a slurry; (b) vibrating the slurry to effect at least a partial stratification of the first aggregate material and the light phase, within the slurry; (c) setting slurry within a mold, to form a set block; and (d) removing the set block from the mold.

[0010] According to further features in the described preferred embodiments, the light phase includes a second aggregate material.

[0011] According to still further features in the described preferred embodiments, the monotonic or substantially monotonic change in density over the length of at least 10cm of the monolithic building block is at least 300 kg/m .

[0012] According to still further features in the described preferred embodiments, the monotonic or substantially monotonic change in thermal conductivity over the length of at least 10cm of the monolithic building block is at least 100% (corresponding to a thermal mass ratio of opposite ends of that length of block being at least 2:1).

[0013] According to still further features in the described preferred embodiments, the monotonic or substantially monotonic change in thermal conductivity over the length of at least 10cm of the monolithic building block is at least 200% (corresponding to a thermal conductivity ratio of opposite ends of that length of block being at least 3:1).

[0014] According to still further features in the described preferred embodiments, the thermal conductivity of the cementitious composite material in the second cross-sectional slice is at most 0.36 W/(m*K), at most 0.32 W/(m*K), at most 0.28 W/(m*K), at most 0.25 W/(m*K), at most 0.22 W/(m*K), at most 0.20 W/(m*K), at most 0.18 W/(m*K), or at most 0.15 W/(m*K), and optionally, at least 0.03 W/(m*K), at least 0.07 W/(m*K), at least 0.10 W/(m«K), at least 0.12 W/(m«K), or at least 0.14 W/(m«K).

[0015] According to still further features in the described preferred embodiments, the second cross-sectional slice has a compressive strength, along the first direction, of at least 0.5 MPa, at least 0.75MPa, at least 1 MPa, at least 1.5MPa, at least 2.5MPa, or at least 4MPa, and optionally, at most 20MPa, at most 15MPa, at most 12 MPa, at most 10 MPa, at most 8 MPa, or at most 6 MPa.

[0016] According to still further features in the described preferred embodiments, a compressive strength ratio of the first and second cross-sectional slices, measured along the first direction, being at least 3: 1, at least 5:1, at least 10:1, at least 20:1, at least 50:1, or at least 100:1, and optionally, at most 1000:1, at most 700: 1, at most 500:1, at most 300:1, at most 200:1, at most 150: 1, or at most 120:1.

[0017] According to still further features in the described preferred embodiments, the thermal conductivity of the second cross-sectional slice is at most 0.32 W/(m*K), at most 0.28 W/(m*K), at most 0.25 W/(m*K), at most 0.22 W/(m*K), at most 0.20 W/(m*K), at most 0.18 W/(m«K), or at most 0.15 W/(m«K).

[0018] According to still further features in the described preferred embodiments, the thermal conductivity of the second cross-sectional slice is at least 0.03 W/(m*K), at least 0.07 W/(m«K), at least 0.10 W/(m«K), at least 0.12 W/(m«K), or at least 0.14 W/(m«K).

[0019] According to still further features in the described preferred embodiments, a thermal conductivity ratio between the first and the second cross-sectional slices is within a range of 0.03 to 0.25.

[0020] According to still further features in the described preferred embodiments, the differential density between the first and second cross-sectional slices is at least 325 kg/m , at least 350 kg/m ³ , at least 400 kg/m ³ , at least 500 kg/m ³ , at least 600 kg/m ³ , at least 800 kg/m ³ , at least 1000 kg/m ³ , at least 1200 kg/m ³ , at least 1400 kg/m ³ , at least 1600 kg/m ³ , at least 1800 kg/m ³ , or at least 2000 kg/m ³ . [0021] According to still further features in the described preferred embodiments, the differential density between the first and second cross-sectional slices is at most 3000 kg/m , at most 2700 kg/m ³ , at most 2400 kg/m ³ , or at most 2200 kg/m ³ .

[0022] According to still further features in the described preferred embodiments, the second phase includes a second aggregate material, the second aggregate material optionally including, or mainly including, particles selected from the group consisting of polystyrene, hemp, cork, expanded glass, light expanded clay aggregate (LECA), pumice, perlite, scoria, and vermiculite.

[0023] According to still further features in the described preferred embodiments, the first aggregate material includes, or mainly includes, particles selected from the group consisting of sand and crushed or fine stone, crushed or fine ceramics, bauxite and barite.

[0024] According to still further features in the described preferred embodiments, a weight ratio of the first aggregate material to the second aggregate material is within a range of 5: 1 to 1000:1, 10:1 to 500: 1, or 20:1 to 500: 1.

[0025] According to still further features in the described preferred embodiments, the thermal mass ratio is at least 2:1, at least 4: 1, or at least 10:1.

[0026] According to still further features in the described preferred embodiments, the thermal mass ratio is at most 16:1, at most 14: 1, or at most 12: 1.

[0027] According to still further features in the described preferred embodiments, the thermal mass ratio is within a range of 2: 1 to 16: 1, 3:1 to 15:1, or 5:1 to 15:1.

[0028] According to still further features in the described preferred embodiments, a void fraction within the block is at most 0.65, at most 0.55, at most 0.50, or at most 0.4.

[0029] According to still further features in the described preferred embodiments, a plurality of the monolithic building blocks includes at least a first monolithic building block, and a second monolithic building block rigidly attached thereto. [0030] According to still further features in the described preferred embodiments, the plurality of monolithic building blocks forms at least a portion of a wall of a building.

[0031] According to still further features in the described preferred embodiments, the plurality of monolithic building blocks forms at least a portion of a ceiling.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The foregoing discussion will be understood more readily from the following detailed description of the invention, when taken in conjunction with the accompanying Figures, in which:

[0033] Figure 1A is a perspective view of a schematic monolithic building block, according to one aspect of the present invention;

[0034] Figures IB, 1C, and ID are cross-sectional views of the monolithic building block of Figure 1A, taken along section lines IB-IB, 1C-1C, and ID-ID in Figure 1A, respectively;

[0035] Figure 2 is a flow chart illustration of a method for fabrication of a monolithic building structure as shown in Figures 1A - ID, according to an aspect of the present invention;

[0036] Figure 3 is a cross-sectional view of an inventive monolithic building block produced according to Example 2, showing the segregation of light aggregate and heavy aggregate along a length thereof;

[0037] Figure 4 is a cross-sectional view of a monolithic building block according to another embodiment of the present invention, as in Figure 3, but in which the light phase is largely made up of gas-containing voids;

[0038] Figure 5A is the cross-sectional view of the monolithic building block of Figure 3, disposed lengthwise; [0039] Figure 5B is a graph of the average block density of the block of Figure 5 A, as a function of position along the length of the block;

[0040] Figure 5C is a graph of the average thermal conductivity of the block of Figure 5A, as a function of position along the length of the block;

[0041] Figure 5D is a graph of the average volumetric heat capacity of the block of Figure 5A, as a function of position along the length of the block;

[0042] Figure 6A is the cross-sectional view of an inventive monolithic building block produced according to Example 17, disposed lengthwise;

[0043] Figure 6B is a graph of the average block density of the block of Figure 6 A, as a function of position along the length of the block;

[0044] Figure 6C is a graph of the average thermal conductivity of the block of Figure 6A, as a function of position along the length of the block; and

[0045] Figure 6D is a graph of the average volumetric heat capacity of the block of Figure 6 A, as a function of position along the length of the block.

[0046] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0047] The principles of the inventive building structure and the inventive methods of producing and for using such a building structure, may be better understood with reference to the drawings and the accompanying description.

[0048] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0049] Reference is now made to Figure 1A, which is a perspective view of a monolithic building block 10 according to one aspect of the present invention, and to Figures IB, 1C, and ID, which are cross-sectional views of the monolithic building block 10 of Figure 1A, taken along section lines IB-IB, 1C-1C, and ID-ID in Figure 1A, respectively.

[0050] As seen in Figures 1A to ID, a monolithic building block 10 according to an aspect of the present invention may include a composite slab or structural slab 12 including a cementitious matrix 14, having embedded therein a first phase, which may include a first aggregate material 16. Embedded within cementitious matrix 14 may be a second phase, which may include a second aggregate material 18. Alternatively or additionally, the second phase may include a gas, typically air, such as void volumes or bubbles 19. The second phase may have an appreciably lower specific gravity with respect to the first phase.

[0051] The dimensions of the block are typically at least 10cm length by 10cm width by 10cm height. More typically, the length is at least 12cm, at least 15cm, at least 18cm, at least

20cm, at least 22cm, or at least 25cm. The length may be within a range of 10-5000cm, 10- 3000cm, 10-1500cm, 10-lOOOcm, 10-500cm, 10-250cm, 10- 100cm, 10-80cm, 10-60cm, 10- 50cm, or 10-40cm. The height and width may be within a range of 10-50cm, 10-40cm, 10- 35cm, or 10-30cm. The length-to-width ratio and length-to-height ratio may be within a range of 1 : 1 to 6: 1, 1 : 1 to 5: 1, 1 : 1 to 4: 1, 1 : 1 to 3: 1, 1.4: 1 to 6: 1, 1.4: 1 to 4: 1, 1.7: 1 to 6: 1, or 1.7: 1 to 4: 1.

[0052] The cementitious matrix or binder may include, mainly (i.e., >50%, by weight) include, or consist essentially of: Ordinary Portland Cement (OPC), calcium aluminate cement, calcium sulfo-aluminate (CSA) cement, lime, hydraulic lime, gypsum, sorel (magnesia) cement, water glass (sodium silicate), and geopolymer cement.

[0053] In some embodiments, the first aggregate material 16 includes particles selected from the group consisting of sand, crushed stone, fine stone, or stone pieces, barite, various carbides, nitrides, fine or crushed ceramics, or other aggregate materials that will be known to those of skill in the art. Typically, such aggregate materials have a specific gravity of at least 2000

3 3 3

kg/m , and/or a bulk density of at least 1200 kg/m or 1400 kg/m .

[0054] In some embodiments, the optional second aggregate material 18 includes particles selected from the group consisting of polystyrene (e.g., expanded polystyrene balls or beads), hemp, cork, polyurethane, expanded glass, light expanded clay aggregate (LECA), pumice, pearlite, scoria, and vermiculite or other light aggregate materials that will be known to those of skill in the art. Typically, such aggregate materials have a specific gravity of at most 1000

3 3 3 3 kg/m , and more typically, at most 800 kg/m , at most 600 kg/m , at most 400 kg/m , at most

3 3 3

300 kg/m , at most 200 kg/m , or at most 150 kg/m . For those materials having a specific gravity well exceeding that of expanded polystyrene (typically about 10-25 kg/m ), the segregation efficiency, under identical conditions, may be somewhat compromised. However, by increasing the vibration time, increasing the flowability (e.g. , increasing the water fraction), and/or reducing the volume fraction of heavy aggregate, the segregation efficiency may be improved.

[0055] In some embodiments, block 10 may have a void fraction therewithin, the void fraction including a plurality of individual void volumes 19. Typically, the void fraction, by volume, is at least 0.05, at least 0.20, or at least 0.30. Typically, the void fraction, by volume, is at most 0.65, at most 0.55, at most 0.50, at most 0.45, or at most 0.35. As used herein, the individual void volumes (that are used in calculating the void fraction) have a maximum volume of 2cm 3. More typically, the individual void volumes are at most 2cm 3 , at most 1.5cm 3 , at most 1cm 3 , or at most 0.75cm 3.

[0056] As seen with particular clarity in Figure IB, the first aggregate material 16 and the second aggregate material 18 disposed or dispersed within cementitious matrix 14 are differentiated along the length L of block 10, thereby forming first and second lengthwise, parallel portions or slices of the block, indicated by reference numerals 20 and 22, respectively.

[0057] Figure 1C shows a cross-section of monolithic building block 10 within first portion

20, whereas Figure ID shows a cross-section of monolithic building block 10 within second portion 22. As seen in Figure 1C, the first portion 20, which is designed to face the interior of a building structure using blocks 10, includes mostly particles of the first aggregate material 16, and relatively few, if any, particles of the second aggregate material 18. Conversely, as seen in

Figure ID, the second portion 22, which is designed to face the exterior of a building structure using blocks 10, includes mostly particles of the second aggregate material 18, and few, if any, particles of the first aggregate material 16. As such, first portion 20 of block 10 has a first average density or specific gravity, and second portion 22 of block 10 has a second average density or specific gravity. Typically, block 10 and first and second portions 20 and 22 may be characterized by at least one of a differential density (or specific gravity) between the first and second portions, a volumetric heat capacity ratio of the first and second portions, and a thermal resistivity of the first and second portions.

[0058] It should be emphasized that first and second portions 20 and 22 may be first and second cross-sectional slices of the block, taken in the same direction. These slices may be adjacent or non-adjacent. Together, the slices may constitute an entire dimension (typically length) of the block, or a portion thereof.

[0059] Figure 3 is a cross-sectional view of a monolithic building block 300 produced according to Example 2 (described hereinbelow). Block 300 includes a cementitious matrix 314, which exists along the entire length of block 300. Embedded in block 300 is a first, or heavy phase, which may include both a first heavy aggregate material (coarse gravel) 316 and a second fine aggregate material (sand) that is difficult to view without magnification.

[0060] Also embedded within cementitious matrix 314 is a second, or light phase, which includes a light aggregate material 318, in this case, expanded polystyrene spheres.

[0061] Block 300 has a total length of Lb, which may be subdivided into three length segments: a first length segment in which the heavy phase is concentrated (Lheavy), disposed at a first end of the block, a second length segment in which the light phase is concentrated (Llight), disposed at opposite end of the block, and typically (but optionally), a third length segment (Lint) disposed longitudinally in-between the first and second segments. In this third length segment, block 300 may have a reduced content of aggregate materials, or may be substantially devoid of at least one aggregate material, such as a heavy aggregate material or a light aggregate material.

[0062] In the exemplary block cross-section shown in Figure 3, Lint is composed almost exclusively of cementitious matrix 314, and is substantially devoid of both heavy and light aggregate materials, and has a length exceeding 3cm. [0063] More generally, Lint may have a length of 0.5 to 6cm, 0.5 to 5cm, 0.5 to 4cm, 0.5 to 3cm, 0.5 to 2.5cm, 0.5 to 2cm, 0.5 to 1.5cm, or 0.5 to 1cm.

[0064] Expressed as a percentage of Lb, Lint may be 2.5 to 30%, 2.5 to 30%, 2.5 to 25%, 2.5 to 20%, 2.5 to 15%, 2.5 to 12%, 2.5 to 10%, 2.5 to 8%, or 2.5 to 5% of Lb.

[0065] Lheavy is the length of first slice or portion 20 shown in Figure IB, while Llight is the length of second slice or portion 22 shown in Figure IB.

[0066] In some embodiments, in the third, lengthwise portion or slice of the block 10, disposed in parallel with first and second portions 20 and 22 and having a length Lint, the concentration or fraction of particles of at least one of the first and second aggregate materials 16,18 (see Figure IB), may be at most 15%, at most 10%, at most 7%, at most 5%, at most 3%, at most 1%, or substantially 0%, by volume.

[0067] In some embodiments, in a third, lengthwise, intermediate portion or slice of block 10, the concentration or fraction of particles of both first and second aggregate materials 16,18, may be at most 15%, at most 10%, at most 7%, at most 5%, at most 3%, at most 1%, or substantially 0%, by volume.

[0068] The volume% is best determined by measuring the surface-area% of each component within the cross-section of the particular portion or slice, and dividing by the total surface-area of that portion or slice. As used herein in the specification and in the claims section that follows, the term "volumetric heat capacity" refers to the volume- specific heat capacity. Volumetric heat capacity has units of thermal energy divided by the product of temperature and volume, and in SI units, J/(m ³ -°K).

[0069] As used herein in the specification and in the claims section that follows, the term "thermal mass" refers to the volume of the constructive element (block, block portion, or a construction material used to produce such a block) multiplied by the volumetric heat capacity. In some embodiments, the differential density between the first portion 20 and the second portion 22 is within a range of 350 to 3500 kg/m 3 , 500 to 3500 kg/m 3 , 650 to 3500 kg/m ³ , 800 to 3500 kg/m ³ , 1000 to 3500 kg/m ³ , 1200 to 3500 kg/m ³ , 1400 to 3500 kg/m ³ , or 1600 to 3500 kg/m . More typically, this differential density is within a range of 800 to 2500 kg/m ³ , 800 to 2200 kg/m ³ , 800 to 2000 kg/m ³ , 800 to 1800 kg/m ³ , 800 to 1600 kg/m ³ , 1000 to 2500 kg/m ³ , or 1200 to 2500 kg/m ³ .

[0071] In some embodiments, the differential density between the first portion 20 and the second portion 22 is at least 300 kg/m . In some embodiments, the differential density between first portion 20 and second portion 22 is at least 350 kg/m 3 , at least 400 kg/m 3 , at least 500 kg/m ³ , at least 600 kg/m ³ , at least 800 kg/m ³ , at least 1000 kg/m ³ , at least 1200 kg/m ³ , at least 1400 kg/m ³ , at least 1600 kg/m ³ , at least 1800 kg/m ³ , or at least 2000 kg/m ³ .

[0072] In some embodiments, the differential density between the first portion 20 and the second portion 22 is at most 3000 kg/m 3 , at most 2700 kg/m 3 , at most 2400 kg/m 3 , or at most 2200 kg/m ³ .

[0073] In some embodiments, the thermal conductivity of the second portion 22 is at most 0.5 W/(m*K). In some embodiments, the thermal conductivity of the second portion 22 is at most 0.48 W/(m*K), at most 0.45 W/(m*K), at most 0.40 W/(m*K), at most 0.35 W/(m*K), at most 0.30 W/(m*K), at most 0.25 W/(m*K), at most 0.20 W/(m*K), at most 0.15 W/(m*K), at most 0.12 W/(m*K), or at most 0.10 W/(m*K). In some embodiments, the thermal conductivity of the second portion 22 is at least 0.05 W/(m*K), at least 0.07 W/(m*K), at least 0.10 W/(m«K), at least 0.15 W/(m«K), or at least 0.20 W/(m«K).

[0074] In some embodiments, the thermal conductivity ratio between the first portion 20 and the second portion 22 is at most 0.3:1, at most 0.25: 1, at most 0.2: 1, at most 0.15:1, at most 0.1:1, at most 0.07: 1, or at most 0.05:1. This thermal conductivity ratio may be at least 0.02, at least 0.025, at least 0.03, at least 0.035, at least 0.04, or at least 0.045. Typically, the thermal conductivity ratio is within a range of 0.03 to 0.25, 0.03 to 0.20, or 0.05 to 0.20.

[0075] The monolithic building block 10 may be included in a monolithic building structure, typically such that first portion 20 (or cross-sectional line 1C) is disposed closer to the interior of the structure and second portion 22 (or cross-sectional line ID) is disposed closer to the exterior of the structure.

[0076] In some embodiments, the monolithic building structure includes a plurality of monolithic building blocks similar to block 10 of Figures 1A to ID, the plurality including at least a first and a second monolithic building block, the first and second monolithic building blocks being rigidly attached to one another. In some embodiments, the plurality of monolithic building blocks form at least a portion of a wall of a building. In some embodiments, the plurality of monolithic building blocks form at least a portion of a ceiling.

[0077] Reference is now made to Figure 2, which is a flow chart illustration of a method for fabrication of a monolithic building block 10 as shown in Figures 1A to ID, according to an aspect of the present invention.

[0078] As seen in Figure 2, at step 200, the first aggregate material 16, optional second aggregate material 18, and cementitious material 14, and an aqueous liquid, such as water, are mixed to form a substantially uniform slurry.

[0079] In some embodiments, a weight ratio of the first aggregate material to the second aggregate material is within a range of 3: 1 to 300: 1.0, 5:1 to 200: 1, or 5: 1 to 150:1.

[0080] In some embodiments, the slurry is created and mixed using a mixer, and is then transferred to a vessel suitable for carrying out the following method steps as described hereinbelow. In other embodiments, the slurry is created and mixed directly in the vessel suitable for carrying out the following method steps.

[0081] In some embodiments, the dimensions of the vessel are suited to the dimensions of a single resulting block 10, with little waste.

[0082] As seen at step 202, the slurry in the vessel is vibrated to effect at least partial stratification of the first and second aggregate materials within the slurry. Vibration may be carried out using any suitable device, such as a vibrating table. The intensity and duration of vibration required for stratification of the first and second aggregate materials is dependent on the specific composition of the slurry and the volume and weight of the vibrated materials. In some embodiments, a suitable intensity of vibration is achieved in the range of 1,000- 10,000rpm (i.e., the RPM of the vibration table motor), more typically in the range of 2,500- 4,500rpm. In some embodiments, the slurry is vibrated for a duration of 15 seconds to 5 minutes, more typically, 30 seconds to 5 minutes or 45 seconds to 5 minutes.

[0083] Should the vibration intensity be too low, there may be insufficient shear forces, and the segregation may be impaired. In addition, the relatively light aggregate (with respect to the cementitious medium) material may be trapped within the heavy aggregate material. Should the vibration intensity be too high, however, segregation may also be impaired, as the relatively heavy aggregate material may settle poorly, while the relatively light aggregate material may be more evenly distributed over the height of the block.

[0084] At step 204, following at least partial stratification of the aggregate materials within the slurry, the slurry is allowed to set within the vessel for a suitable duration, for example, 24 hours.

[0085] Once the slurry has set within the vessel, the resulting block is removed from the vessel, at step 206, and cured (e.g. , for an additional 14 days), typically under room conditions. EXAMPLES

[0086] Reference is now made to the following Examples, which together with the above description, illustrate the invention in a non-limiting fashion.

[0087] The main ingredients used in effecting these Examples are identified hereinbelow:

[0088] binder - cement: OPC CEM-1 52.5R, Nesher Industries (Israel);

[0089] gravel - 4.75-9.5 mm, Dragot quarry, Negev Industrial Minerals (Israel);

[0090] sand - silica sand 30-40 - Negev Industrial Minerals (Israel);

[0091] expanded polystyrene - Versalis S.P.A.;

[0092] cement retardant - sodium tripolyphosphate;

[0093] cellulose ether - Tylose MH6000 YP4;

[0094] polymer binder powder - DA 1400;

[0095] cellulose fibers - Arbocell 500 ZZC ;

[0096] air entrainment agent - Hostapur OSB ;

[0097] superplasticizer - Melment FlOx

[0098] Various instruments used in conjunction with the Examples are identified hereinbelow:

[0099] Mixing of the slurry was performed using a Hobart Legacy 5 liter mixer (Hobart Corporation, Troy, Ohio).

[00100] Vibration of the slurry was performed using a CONTROLS vibration table 55- C0159L (Controls s.r.L, Cernusco sul Naviglio, Italy).

[00101] Cutting of the block was performed using a diamond saw (SHATAL TS 351).

EXAMPLE 1 [00102] Cement binder (typically lOOOg), heavy aggregate, light aggregate, water, and additives were introduced into a mixing vessel. Various additives, e.g., for improving or controlling process parameters including workability and rheology, were also added, according to the proportions provided in Table 3. The contents of the vessel were then mixed for approximately 1 minute to form a substantially uniform slurry.

[00103] Subsequently, the slurry was poured into a substantially cylindrical mold having a diameter of 10cm and a height of 20cm. The mold was transferred to a vibration table and was vibrated at 40% of the maximal intensity of the vibration table, typically for 15-180 seconds.

[00104] The vibrated slurry was allowed to set for 24 hours, and was then removed from the mold, cured for an additional 14 days under room conditions, and cut with a diamond saw for observation of the stratification of the aggregates in the resulting block. The resulting block was clearly divided into a first portion and a second portion. Generally, the first portion included mostly heavy aggregate, but also some light aggregate (polystyrene), while the second portion included mostly light aggregate, but also a small amount of heavy aggregate.

EXAMPLES 2-15

[00105] The procedure used in Example 1 was repeated in Examples 2-15, using heavy aggregate materials of various sizes, and combinations thereof, along with light aggregate materials of various sizes, and combinations thereof. The vibration time was also varied, as shown in Table 2. The additives added, as a weight percentage of the cement binder, are provided in Table 3.

[00106] Calculation of density was performed as follows: a tape measure or ruler was used to measure the dimensions of the slices. The weight of each slice, divided by the respective resultant volume, equals the density (or in unities s form— the specific gravity). Table 1

[00107] Calculation of density was performed as follows: a tape measure or ruler was used to measure the dimensions of the slices. The weight of each slice, divided by the respective resultant volume, equals the density (or in unities s form— the specific gravity).

[00108] Specific heat (Thermal mass) and thermal conductivity (resistivity) were measured using the Hot Disc method performed using a THERMAL CONSTANT ANALYZER TPS 2500 S. Table 2

Table 3

[00109] The blocks obtained were characterized by a clear segregation pattern along the length of the block: the first portion or slice contained mostly gravel, with minute amounts of polystyrene, while the second portion or slice contained mostly polystyrene, with small amounts of gravel. This has been described hereinabove with respect to Figure 3.

EXAMPLE 18

[00110] The procedure used in Example 1 was repeated in Example 18, using the formulation of Example 2. After curing, the cured block was heated in a furnace at 140°C for 48 hours.

[00111] Figure 4 is a cross-sectional view of the monolithic building block 400 obtained. The polystyrene was substantially consumed, leaving (in this case, generally spherical) voids 419 as the light phase, in place, or largely in place of, the polystyrene particles.

[00112] The expanded polystyrene for use in conjunction with the present invention may be of a widely varying average diameter, e.g., at least 0.5mm, at least 0.75mm, at least 1mm, at least 2mm, at least 4mm, or at least 6mm, typically at most 18mm, at most 15mm, at most 12mm, or at most 8mm, and more typically, 0.50- 15mm, 0.75- 12mm, l-12mm, or 1-lOmm. Thus, the void volumes formed may be characterized by these average diameters.

[00113] As in the other blocks described hereinabove, block 400 includes a cementitious matrix 414, having embedded therein a first phase, which includes a first, heavy aggregate material 416, in this case, coarse gravel.

[00114] Figure 5A is the cross-sectional view of the monolithic building block of Figure 3, disposed lengthwise. Figure 5B is a graph of the average block density of the block of Figure 5 A, as a function of position along the length of the block {i.e., the distance from the heavy end of the block), in cm. The density of the heavy segment of the block is approximately 2000 kg/m 3 , and the density of the light segment of the block is approximately 500 kg/m 3 , and 400 kg/m towards the end of the block. Figure 5C is a graph of the average thermal conductivity of the block of Figure 5A, as a function of position along the length of the block. The average thermal conductivity of the heavy segment of the block is approximately 1.4 W/mK, while the average thermal conductivity of the light segment of the block is approximately 0.12 W/mK. Figure 5D is a graph of the average volumetric heat capacity of the block of Figure 5A, as a function of position along the length of the block. The volumetric heat capacity of the heavy segment of the block is approximately 2.5 MJ/m K, while the average thermal conductivity of the light segment of the block is approximately 0.65 W/mK.

[00115] Similarly, Figure 6A is the cross-sectional view of a monolithic building block of Example 17, disposed lengthwise. Figure 6B plots the average block density of the block of Figure 6A, as a function of position along the length of the block. Figure 6C plots the average thermal conductivity of the block of Figure 6A, as a function of position along the length of the block. Figure 6D plots the average volumetric heat capacity of the block of Figure 6A, as a function of position along the length of the block.

[00116] As used herein in the specification and in the claims section that follows, the term "percent", or "%", refers to percent by weight, unless specifically indicated otherwise.

[00117] As used herein in the specification and in the claims section that follows, the term "contour volume", with regard to a block, or portion or slice of the block, refers to the smallest volume encompassed by the block, or by the portion of the block. By way of example: a cubic block weighing 1.67kg has a length of 20cm, and a single 2cm x 2cm hole passing completely through one dimension of the cube, parallel to the cube face. The contour volume of the block would be 20cm x 20cm x 20cm, less the hole: 2cm x 2cm x 20cm, or 0.72 liters. The average density is 1.67/0.72 = 2.32 kg/liter.

[00118] Similarly, as used herein in the specification and in the claims section that follows, the definition of a property of a "cementitious composite material" is meant to exclude macroholes or filled macroholes (e.g. , holes filled with polymer and the like) disposed adjacent to that cementitious composite material. [00119] As used herein in the specification and in the claims section that follows, the term "macrohole", with regard to a portion of a construction block, refers to any hole or filled hole having a cross-sectional area exceeding 2cm 2 , or having a volume exceeding 2cm 3.

[00120] As used herein in the specification and in the claims section that follows, the term "average density", with regard to a block, or portion of the block (e.g., a cross-sectional slice), is evaluated by dividing the weight of the block or portion thereof, in kg, by the respective contour volume, in liters, of the block or portion thereof.

[00121] As used herein in the specification and in the claims section that follows, the term "monolithic building block", refers to a building block devoid of an adhesive layer connecting between sections of the monolithic block, or, in the case of a building block having such an adhesive layer connecting between sections of the building block, the term "monolithic building block", refers to a continuous portion of that block, that is devoid of an adhesive layer.

[00122] As used herein in the specification and in the claims section that follows, the term "intimately dispersed" is used as is used in the art.

[00123] As used herein in the specification and in the claims section that follows, the term "monotonic", and the like, with regard to a change in a parameter, refers to a change that is solely a positive change (i.e., having a positive slope) or a negative change (i.e., having a negative slope).

[00124] As used herein in the specification and in the claims section that follows, the term "substantially monotonic", and the like, with regard to a change in a parameter, refers to a change that, within 5%, is solely a positive change (i.e., having a positive slope) or that, within 5%, is solely a negative change (i.e., having a negative slope). Thus, in Figure 6D, by way of example, the specific heat capacity plotted as a function of distance along the length of the block decreases in a substantially monotonic fashion. [00125] As used herein in the specification and in the claims section that follows, the average particle size or average diameter may be evaluated using the ASTM Sieve Series. For evaluating the average particle size or average diameter of particles in a cross-section of a block or block segment, the total measured area of the particles may be divided by the number of particles to obtain the average area (Aavg), and the average particle size or average diameter (Davg) may be characterized according to the formula:

Davg = (4 Aavg/n) ^½ .

[00126] It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. Similarly, the content of a claim depending from one or more particular claims may generally depend from the other, unspecified claims, or be combined with the content thereof, absent any specific, manifest incompatibility therebetween.

[00127] Co-pending, unpublished Patent Application No. GB 1513077.6 is hereby incorporated by reference for all purposes as if fully set forth herein.

[00128] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.