Structure of road soil cement compositions modified by complex additive based on organosilicon compounds and electrolytes

Abstract

The complex introduction of organosilicon compound (octyltriethoxysilane) and electrolyte (sodium hydroxide) maximizes the frost resistance and strength of soil cement. However, the effect of complex additive based on octyltriethoxysilane and sodium hydroxide on the soil cement structure has not been sufficiently studied. Therefore, the aim of this work was to study the phase composition of hydrated newgrowths and soil minerals in soil cement with optimal content of complex additives. The study was conducted by methods of complex thermal analysis, X-ray powder diffraction and electron microscopy. On the XRD pattern of the sample with and without complex additive, we marked identical peaks of soil minerals, unhydrated cement clinker minerals and hydrated newgrowths. In the result of differential thermal analysis, we determined that soil cement with complex additive is characterized by the smaller amount of free calcium hydroxide formed, as well as saturation of the soil complex with sodium ions. In the soil cement sample with complex additive, we observe a smaller amount of coagulated soil aggregates in comparison with the sample without an additive. Complex additive contributes to the formation of a more dense and uniform structure of soil cement, reduces the amount of adsorption water associated with clay minerals, reduces the formation of free calcium hydroxide, which increases the physicomechanical properties of the resulting material.