Use of coarse-grained soils reinforced with cement in the construction of pavement layers

Abstract

Abstract. Problem. When designing and building pavements, it is necessary to make full use of local low-strength stone materials reinforced with inorganic binders (cement, lime, activated ash, etc.). The economic feasibility of using cement soils for paving in areas not provided with local stone materials is particularly significant. Under these conditions, the cost of 1 m² of cement-soil layer is often 1.5-2 times lower than the cost of 1 m² of a uniform layer of imported materials. layer of imported materials. When using the technology of soil strengthening with inorganic binders, there is no need for a significant amount of transport, as it is possible to strengthen the local soil, which is located nearby, and only binders can be delivered to the work site. It is possible to unload cement in the car for distribution of binder directly on a place of carrying out works. Strengthening local soils can provide a solid foundation. Soils suitable for cement hardening are much more common than stone materials. The strength of coarse-grained soils depends on the constituent rocks and the density of laying. Fragments of igneous rockshave the greatest strength, sedimentary rocks have the lowest. The most active part of the cement-soil mixture, which provides the creation of a new structure of the reinforced soil, is cement. As a result of the interaction of cement with water, with salts present in the soil and partially with the fine part of the soil, a new water-resistant crystallization structure appears in the strengthened soil. The strength of this structure is determined mainly by the composition and quality of cement. During soil treatment with cement, hydration processes, as well as other chemical reactions will increase or slow down dependingon the chemical and mineral compositions of cement, the nature of the soil and its physicochemical state at the time of treatment. When strengthening soils with cements of the same brands, but of different mineral composition, cement soils with different properties will be obtained. Therefore, the final decision on the suitability of cement and its dosage is made based on the results of tests of cement soil samples. In each case, the decision to use highquality cements or additives that increase thestrength and frost resistance of the cement soil must be economically justified.