Effect of salinity on rheological and strength properties of cement-stabilized clay minerals

Abstract

This paper presents an experimental investigation into the effect of salinity on Atterberg limits, flowability, viscosity and strength properties of cement-stabilized clay minerals. Three groups of clay minerals (illite, kaolinite and montmorillonite) were obtained. Specimens with different porewater salinities were prepared by mixing the air-dried clays with sodium chloride (NaCl) at various salt concentrations (i.e., 0%, 2% 4%, 6% and 8%). Atterberg limits test results indicated that liquid limit and plasticity index decreased insignificantly with increasing salinity for Kaolinite and illite but significantly for montmorillonite. Flow test results indicated that of all specimens of three groups of clay minerals with or without adding cement consistently increase with increasing salinity. The flow value of montmorillonite increased more significantly than kaolinite and illite. Viscosity test results indicated that all the specimens tested behave as Bingham plastic. Flow value consistently decreased with increasing dynamic viscosity or yield stress, regardless of clay mineralogy, porewater salinity and cement amount. Strength test results indicated that all cement-stabilized specimens exhibit strain softening behavior. Unconfined compressive strength for three groups of clay minerals stabilized with cement consistently decreased with increasing salinity indicating that the presence of salt had an adverse effect on the development of strength.     

X射线荧光光谱分析中熔融制样法的改进与应用

对于高硅、高铝、高铁等类的酸性样品,在熔融制样时,通过加入碱性氧化物来提高熔融体的碱性,消除酸性熔融体的不熔物,提高熔融体的流动性,使熔融体混和均匀,提高了制样的重现性,使准确度得到了提高。