Experimental Study on PVA-MgO Composite Improvement of Sandy Soil

Abstract

Materials with violent hydration reaction such as cement are used to solidify sandy soil slopes, which will cause destructive damage to the ecology of the slopes. In this paper, polyvinyl alcohol (PVA) and activated magnesium oxide (MgO) are used to improve sandy soil, and the effects of the dosage and curing age of modifiers on the mechanical properties of solidified sandy soil are studied. The dry–wet durability of the composite improved sandy soil is analyzed using a dry–wet cycle test, and the improvement mechanism of PVA and activated magnesium oxide is revealed using an electron microscope. The results show that the curing effect of polyvinyl alcohol and activated magnesium oxide on sand particles is better than that of polyvinyl alcohol alone. The compressive strength of improved soil samples increases with the increase of curing time, and magnesium oxide as an improved material needs appropriate reaction conditions to give full play to its role. The compressive strength of composite improved samples increases first and then decreases during the dry–wet cycle. Through the observation of microstructure, it can be seen that the cementing material wraps and connects the sand particles, and the cementing material of the sample after the dry–wet cycle develops more completely; if the magnesium oxide content is high, cracks may appear inside the sample.

Modification Effect of Nano-Clay on Mechanical Behavior of Composite Geomaterials: Cement, Nano-Silica and Coastal Soft Soil

“…At present, many scholars at home and abroad have carried out much research on the use of nano-materials to modify coastal soft soil and proved its effectiveness [4,[15][16][17][18]. Compared with traditional materials, nano-materials have the characteristics of great specific surface area and minimal size, which have the ability to speed up cement hydration during the hydration reaction to effectively enhance the mechanical strength and durability of cement soil [19,20], and reduce environmental pollution, providing great possibilities for the sustainable development of the construction industry.…”