Effect of curing, capillary action, and groundwater level increment on geotechnical properties of lime concrete: Experimental and prediction studies

Abstract

Lime concrete and lime treatment are two attractive techniques for geotechnical engineers. However, researches have rarely been carried out to study the effects of moisture and capillary action due to increasing groundwater level on geotechnical properties of lime concrete. The aim of this study is to investigate the effects of curing time and degree of saturation on some of geotechnical properties of lime concrete such as unconfined compressive strength (UCS), secant modulus (Es), failure strain, brittleness index (IB), and deformability index (ID) using unconfined compression tests. First of all, geotechnical and chemical properties of used materials were determined. After curing times of 14 d, 28 d, 45 d, and 60 d in laboratory condition, the specimens were exposed to saturation levels ranging from 0 to 100%. The results showed that the moisture and curing time have significant effects on the properties of lime concrete. Based on the results of scanning electron micrograph (SEM) test, it was observed that the specimen was characterized by a rather well-structured matrix since both the filling of a large proportion of the coarse-grained soil voids by clay and the pozzolanic activity of lime led to retaining less pore water in the specimen, increasing the UCS and Es, and consequently resisting against swelling and shrinkage of the clay soil. Moreover, due to the pozzolanic reactions and reduction of water, by increasing the curing time and decreasing the degrees of saturation, UCS, Es, and IB increased, and ID decreased. Based on the experimental results, a phenomenological model was used to develop equations for predicting the properties in relation to the ratio of degree of saturation/curing time. The results showed that there was a good correlation (almost R2 > 90%) between the measured parameters and the estimated ones given by the predicted equations.