Experimental Study of Cemented Soil under Na 2 SO 4 Corrosive Condition

Abstract

The Na(+) and SO(4)(2) – in the surrounding environment of cement-soil piles may affect the mechanical properties of cemented soil, which may cause some serious damage to structures. In order to simulate and study the erosion effect process, a series of unconfined compressive tests were conducted on the cemented soil blocks which were cured in the Na(2)SO(4) solutions with various concentrations and ages. For comparison purposes, photos of the blocks were taken and the Na(+) and SO(4)(2) – concentration of the Na(2)SO(4) solution were recorded after the curing process. The testing results show that the Na(2)SO(4) solution does make the cement-soil block change, and the influence of NaSO(4) to the blocks is increasing with the concentration of Na(2)SO(4) and curing time increasing. The unconfined compressive strength of cemented soil block is decreased with the increasing of solution concentration, increased with the curing time. An a coefficient α is put forward to predict the modification of the compressive strength of cemented soil in various concentration of Na(2)SO(4) solution. The Na(+) and SO(4)(2)– concentrations of the solutions decrease with the corrosive time. Chemical analysis indicates that the corrosion of Na(2)SO(4) solution to cemented soil is a composite action including dissolving and crystallizing corrosions. Finally, a strength model of cemented soil is set up based on the relationship of compressive strength and Na(+) and SO(4)(2)– concentrations, and its limit is also described. The model may be used in practical design in the future based on the concentrations of Na(+) and SO(4)(2)– of corrosive environment.