SOIL REINFORCEMENT USING CALCIUM PHOSPHATE COMPOUNDS

Abstract

For the purpose of using calcium phosphate compounds (CPCs) for ground improvement measures, such as the reinforcement of soils and rocks, a fundamental examination of new grouting materials composed of CPCs (CPC-Chem) is required. Therefore, in this study, we have first analyzed the ideal conditions for CPC precipitation by in vitro examination of the different mixtures of calcium and phosphate stock solutions. Following that, Toyoura sand was cemented with CPCs and the cured specimens were analyzed by using unconfined compressive strength (UCS) tests. Similarly, Toyoura sand was cemented with a mixture of CPC-Chem and tricalcium phosphate (TCP) powder and then cured; these specimens too were then analyzed by using UCS tests. Test results indicate an improvement in UCS of TCP-added specimens when compared to that of no-additive (CPCChem alone) specimens. Besides, the morphology and elemental composition of the specimens were analyzed by using scanning electron microscopy (SEM) and energy dispersive X-ray fluorescence spectroscopy (EDX). The results obtained from the systematic analyses indicate the practical feasibility of using both the combination of CPC-Chem and TCP powder as well as the CPC-Chem alone as chemical grouts for ground improvement measures.