A durabilidade de solos lateríticos estabilizados com cimento e aditivos.

Abstract

One of the major factors restricting the use of soil cement as an structural material, for the construction of bases and subbases in road pavsflient, is the uncertainty of its behaviour when exposed to cyclic traffic loads and cyclic volumetric changes arising from exposure to environmental conditions. This dissertation investigates the behaviour of three lateritic soils from the State of Paraiba, Brazil stabilized with cement, with cement and 2 percent lime as an additive and with cement and 2 percent cutback bitumen as an additive. The durability of the systems in measured in terms of changes of indirect tensile strength when these are exposed to a process of dry-wet cycles to induce volume changes. Unconfined compression tests are carried out to study the influence of cement percentage and curing time, and for the determination of the minimum amount of cement required to attain ah arbitrary value of unconfined compressive strength, which is used for the specimens prepared for the durability study. The results obtained, show clearly that the actual brazilian method for the design of soil cement systems does not allow to assess the durability of theses systems. It shows furthermore' that Hme and cutback bitumen are highly effective to improve the durability of the systems. Qualitative interpretations of the mechanisms by which lime and cutback biturrieh improve the durability of the systems is offered.'