Modified Powdered Mass for Treatment of Soils and Loose Building Materials Technical Field The invention concerns Modified Powdered Mass for treatment of soils and loose building materials containing caustic lime and/or calcareous hydraulic binders, and a modification component that is not toxic and is environmentally friendly.

Background Art Powdered caustic lime has been still used for treatment and stabilization of soils in different branches of the building industry. The application of caustic lime itself produces high level of dustiness, which adversely influences agricultural crops, soils, as well as the environment on site and in its surroundings. The mentioned disadvantages have been partially removed by he use of modified lime pursuant to PCT W098/23705 which contains, besides caustic lime, also a liquid additive (modification component) consisting of polyolefins, alkanes and cycloalkanes.

Modified lime is prepared by adding the above-mentioned liquid additives to caustic lime, or to the hydraulic binder, or even during grinding caustic lime or the hydraulic binder. The technology of application of modified lime is utilized especially in construction of road and highways, railways and railway corridors, in construction of airport aprons, parking lots, embankments and tunnels. PCT W098/23705 mentions the use of white mineral oil, which is the mixture of alkanes and cycloalkanes in the volume of 68 % and 32 %, respectively, its average molecular weight is 340 to 360 and its kinematic viscosity at 40° C is 15 cP. The use of polyolefins, especially poly- a-olefins and poly-intra-olefins is further stated here. The disadvantage of these additives, that are known up to now, is especially their low biological degradability and slightly worse ability of dust particles dispersion.

Disclosure of Invention The mentioned disadvantages are removed by the Modified Powdered Mass for treatment of soils and loose building materials containing caustic lime and/or calcareous hydraulic binders and a modification component, in which, according to the invention, the modification component consists of linear olefins containing 10 to 24 carbon atoms, alone or in their mutual combination,

or in mixture with their isomers. For the purposes of this invention, linear olefins are unbranched hydrocarbons with straight chain having at least one carbon-carbon double bound present in the chain. Linear olefins contain from 12 to 24 carbon atoms, more advantageously from 14 to 18 carbon atoms. Industrially available linear olefins with 14 to 18 carbon atoms, or with a higher number of carbon atoms, have the required properties of synthetic hydrocarbons suitable as a modification component. Such properties are, among others, kinematic viscosity, inflammation point, solidification point, reactivity and minimum toxicity. It has been found that mixtures of linear olefins can, as an advantage, contain mixtures consisting of C14, C16 or Cl8, normal, a-and linear internal olefins or their combination, while the invention is not limited only to these synthetic hydrocarbons.

Linear olefins used according to this invention can be produced by different ways that are well-known to any professional in the branch. Such ways include cracking of linear aliphatic hydrocarbons, metathesis or disproportionation of olefins, especially a-olefins, ethylene oligomerization, dehydrogenation of lineral aliphatic hydrocarbons, and isomerization of the double bond of normal a-olefins etc.

Mixtures consisting mainly of Cl4 normal a-olefins are very favorable. Especially favorable are the mixtures consisting of 67-74 % of volume of Cl4 and 26-33 % of volume of Gig linear a-olefin. In some cases, Cl4 normal a-olefins can be mixed with isomerized C16 to C24 products to produce mixtures with suitable properties for preparation of Modified Powdered Mass.

Kinematic viscosity of the modification component is an important parameter. The values of kinematic viscosity for the modification component consisting of Cl4 to C1g linear olefins alone or in their combination range from 3.1 to 3.9 cP, which enables a better dispersion of the smallest particles in the caustic lime and hydraulic binders. The result is considerable reduction of dust emissions without any unfavorable impact on the fluidity of the product and its reactivity.

Another requirement for the modification component is that it should have a relatively high inflammation point for reasons of safety. It would be an advantage if the temperature is above 90° C, especially advantageous is the inflammation point above 110° C.

The modification component according to this invention considerably reduced dustiness of Modified Powdered Mass. The reactivity of tbo°c approached the reactivity of powdered caustic lime.

The modification component, with regard to its physicochemical properties, enables very good homogenization in treating Modified Powdered Mass and its subsequent application.

The modification component, according to the invention, has high biological degradability ranging from 97 to 99 % in 21 days (determined according to the test CEC-L-33-T-82).

Modified Powdered Mass is not toxic, is environmentally compatible, it improves mechanical properties of soil and loose building materials, e. g. of power plant air dust, blast- furnace cinder etc. , and it can be used immediately.

The invention will be explained in more details using examples of factual execution.

Examples Example 1 0.6 % of volume of 1-decene was added to 100 g of caustic lime, and the mixture was intensively mixed at the temperature of 20° C during the period of 5 minutes. The same was done with samples of 0.8 and 1.0 % of volume of the modification component. Dustiness (%) and reactivity t6ooc (min) of the individual samples of Modified Powdered Mass are stated in the following table: Concentration (% of volume) Dustiness (%) Reactivity t6ooc (min) of the modification component unmodified lime 59.0-61. 0 3.0-3. 2 0.6 46.7 3.1 0.8 44.9 3.3 1.0 42.0 3.4 Example 2 0.6 % of volume of 1-tetradecene was added to 100 g of caustic lime, and the mixture was intensively mixed at the temperature of 20° C during the period of 5 minutes. The same was done with samples of 0.8 and 1.0 % of volume of the modification component. Dustiness (%) and reactivity t6ooc (min) of the individual samples of Modified Powdered Mass are stated in the following table:

Concentration (% of volume) Dustiness (%) Reactivity t6ooc (min) of the modification component unmodified lime 59.0-61. 0 3.0-3. 2 0.6 56.8 3.2 0.8 52.4 3.3 1.0 50.8 3.4 Example 3 0.6 % of volume of mixture consisting of 74 % of 1-tetradecene and 26 % of 1-octadecene was added to 100 g of caustic lime, and the mixture was intensively mixed at the temperature of 20° C during the period of 5 minutes. The same was done with samples of 0.8 and 1.0 % of volume of the modification component. Dustiness (%) and reactivity t6o°c (min) of the individual samples of Modified Powdered Mass are stated in the following table: Concentration (% of volume) Dustiness (%) Reactivity t6oDc (min) of the modification component unmodified lime 59.0-61. 0 3.0-3. 2 0.6 51.3 3.2 0.8 49.0 3.2 1.0 47. 3 3. 4 Example 4 0.6 % of volume of 1-octadecene was added to 100 g of caustic lime, and the mixture was intensively mixed at the temperature of 20° C during the period of 5 minutes. The same was done with samples of 0.8 and 1.0 % of volume of the modification component. Dustiness (%) and

reactivity t6o°c (min) of the individual samples of Modified Powdered Mmass are stated in the following table: Concentration (% of volume) Dustiness (%) Reactivity t6ooc (min) of the modification component unmodified lime 59.0-61. 0 3.0-3. 2 0.6 50.0 3.4 0.8 47.9 3.4 1.0 46.8 3.5 Example 5 0.6 % of volume of mixture consisting of 50 % of 1-decene and 50 % of isomer of C20-C24 was added to 100 g of caustic lime, and the mixture was intensively mixed at the temperature of 20° C during the period of 5 minutes. The same was done with samples of 0.8 and 1.0 % of volume of the modification component. Dustiness (%) and reactivity t6ooc (min) of the individual samples of Modified Powdered Mass are stated in the following table: Concentration (% of volume) Dustiness (%) Reactivity t6ooc (min) of the modification component unmodified lime 59.0-61. 0 3.0-3. 2 0.6 51.0 3.6 0.8 49.0 3.6 1.0 47.2 3.5 The used values for concentrations of 0.6-1. 0 % of volume of the modification component are optimum. With higher concentration of the modification component, its effect is not so distinct and the possibility of problems in manipulation with Modified Powdered Mass raise.

The dustiness of Modified Powdered Mass has been determined by means of a comparative method based on determination of loss of the finest portion of lime during blowing- through with air. The results have been compared to the values of unmodified lime.

The determination of reactivity of unmodified lime and of Modified Powdered Mass is based on measurement of temperature that is released due to exothermic reaction with water, in dependence on reaction time. The above-mentioned measurements have been performed in harmony with the Standard CSN EN 459-2.

Industrial Applicability According to the invention, the Modified Powdered Mass can be taken advantage of in building industry, especially in construction of roads, highways, airport, parking lots, tunnels, in railway building and chemical industry.