Evaluation of Soil-Cement Properties With Electrical Resistivity

Abstract

The quality control of soil-cement during construction would benefit from a cost and time efficient tool for evaluating the soil-cement performance. The degree of cement mixing in ground improvement applications is key to the outcome of the engineering performance of cement-based barrier systems for remediation systems (i.e. strength and hydraulic conductivity) as well as the control of cement and water in the mixture. The potential to use simple, yet accurate, rapid sensors to determine the mixing quality of soil-cement would allow for confidence that the final quality of the soil-cement system will perform as intended. The objective of this research was to examine Electrical Resistivity (ER) measurements of mixed and uncured soil-cement samples and assess whether it can be used to predict strength and hydraulic conductivity properties for hardened soil cement samples.

To fulfill this objective, a series of hydraulic conductivity and unconfined compressive strength tests were performed on hardened samples in parallel with ER testing on uncured soil-cement samples with the same mix designs and bulk densities of the samples used in the hydraulic conductivity and unconfined compressive strength testing. It is generally found that ER is very sensitive to the changes in water content, cement content and density but it is difficult to distinguish between simultaneous changes in cement content and water content. Results of hydraulic conductivity and unconfined compressive strength testing suggest that the molding water play a large role in the resulting hydraulic conductivity and unconfined compression strength for a given cement content. The results show that although ER could detect changes in water content in soil-cement mixtures for given cement content, it would be difficult to relate ER measurements to hydraulic conductivity and unconfined compressive strength tests.