Micro–macro properties of plastic concrete anti-seepage wall materials mixed with low-liquid limit clay

Abstract

In this study, the micro–macro properties of plastic concrete mixed with low-liquid limit clay were explored, including the mechanical properties, deformation, impermeability, triaxial stress–strain curve, hydration products, phase composition, and pore structure. The results showed that the strength of the plastic concrete decreased with the increase in clay content. When the clay content was 140 kg/m 3 , the compressive strength and elasticity modulus/strength ratio at 28 days were 3.77 MPa and 316, respectively. The average water-absorption rate of plastic concrete was 10.4%, and the relative permeability coefficient was about 10 −7 −10 −8 cm/s. The stress–strain curves obtained from the triaxial test indicate softening behavior, and the volume change–axial strain curves indicate expansion. The variation in strength showed good linearity with the increase of confining pressure, and the corresponding model parameters were obtained. In addition, micro-analysis showed that the types of hydration products in the hardened paste with different clay contents were almost the same, but the intensity of each diffraction peak was different. As the curing age increased, the degree of hydration of the paste increased, internal pore diameter became smaller, and structural integrity was improved. This study aims to enable the use of local low-liquid limit clay resources to reduce engineering cost and adjust the performance of concrete.