Mechanical behavior and durability of a typical frictional cohesive soil from Rio Grande do Sul/Brazil improved with Portland cement

Lateritic soils are typical of tropical and subtropical climate regions, whose coverage is wide in Brazilian territory. These soils are formed by the leaching of oxides and silicates and are found in unsaturated conditions with a high void ratio due to the presence of macropores and micropores. As a result, the soil has drained behavior and high compressibility. Given these peculiarities, the use of cementing agents can be a suitable solution to promote modifications on the soil's physicochemical properties to affect bearing capacity and stiffness. This study focuses on the mechanical behavior of typical cohesive frictional soil in the city of Passo Fundo (Southern Brazil) improved by Portland cement of high initial strength (Type III) based on the adopted amount of cement C (%) and gamma d. Initially, unconfined compression strength tests (q(u)) were performed for cement contents of 3%, 6%, 9%, and 12%, and gamma(d) equal to 16.4 kN/m(3), 15.4 kN/m(3), 14.4 kN/m(3), 13.6 kN/m(3), and 12.7 kN/m(3), followed by ultrasonic pulse velocity tests to determine the G(0). Then, tensile tests were performed through Splitting Tensile Test (q(t)) considering gamma(d) of 16.4 kN/m(3), 15.4 kN/m(3), and 14.4 kN/m(3) for cement contents of 3%, 6%, 9%, and 12%. Finally, the improved soil was studied using durability tests under wetting/drying conditions with gamma(d) of 16.4 kN/m(3), 15.8 kN/m(3), 14.5 kN/m(3) and cement content of 3%, 6%, 9%, and 12%. The results indicate that C and gamma(d) are sufficiently significant factors in understanding soil's behavior regarding wetting/drying of the mixtures, in that order. Finally, normalized curves of q(u), q(t), G(0) and L-M and V-R were developed as a function of the adjusted q forward slash eta C-iv for practical purposes of dosages for ground improvement.

Automated summary

This study focuses on the mechanical behavior of cohesive frictional soil in Passo Fundo, Brazil, improved by Portland cement of high initial strength. The results show the significant effects of cement content and dry density on soil behavior and provide normalized curves for practical dosages of ground improvement.