Mechanical Improvement of a Fine-Grained Lateritic Soil Treated with Cement for Use in Road Construction

Abstract

The mechanical strength of a fine-grained lateritic soil treated with CEMII/BM 32.5 N cement up to 9% by weight of dry soil and prepared at three different molding water contents was investigated by means of California bearing ratio (CBR), unconfined compressive strength (UCS), indirect tensile strength (TS), and triaxial shear tests. The effect of cement treatment on the microstructure of the lateritic soil was investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The results indicated that cement improved the performance of lateritic soil, particularly at the optimum moisture content (OMC) and dry side of optimum (ωDRY), thus offering the possibility of using the tested lateritic soil in road pavement layers. Furthermore, soils with 6 and 9% cement addition satisfied the strength requirements so that lateritic soil can be used as a base course in rigid pavements. The results of triaxial shear tests revealed the existence of two types of behavior, namely, a ductile behavior for untreated soil and brittle behavior for cement-treated soil. These positive impacts are mainly related to the fact that cement addition gives way to the formation of ettringite, calcite, portlandite, and calcium silicate hydrates (afwillite and tobermorite), which derive principally from cement hydration.