A influência da cal nas propriedades de engenharia de solos lateríticos.

Abstract

issertation deals with the effect of the treatment with lime on the engineering properties of three laterized red soils in the State of Paraíba, Brazil. The calcitic and dolomitic limes were mixed with the soil in two concentrations: two and five percent, of the dry weight of the soil, in each of the three soils, having been researched the following properties: 1. The effect of the limes on the plasticity properties and soil compaction. 2. The influence of wharves on the CBR ratio versus soil compaction moisture content when subjected to seven days of curing and four days of immersion. 3. The influence of the quays on the CBR ratio versus the moisture content of compaction of the three soils when the CBR test was carried out immediately after compaction. 4. The influence of the docks on the resistance to penetration of the cone, of the three soils, measured by the cone penetrometer test. The results obtained clearly showed that the plasticity properties are modified in the same proportion by the two types of lime. The liquidity limit was reduced to a greater extent than the plasticity limit, as a result the plasticity index of the three soils was reduced. The maximum dry bulk density was in all cases less than the maximum dry bulk density of soils without lime, while the corresponding optimum moisture content was always higher. Dolomitic lime produced noticeably greater variations than calcitic lime. A phenomenological explanation is offered in the light of these results. Calcitic lime was found to behave better in terms of strength gains, measured by the CBR test, when the soils were subjected to curing and immersion, while for the soils tested immediately after compaction, dolomitic lime gave better results. Considering the arbitrary parameter of reactivity used, the L-3 soil (Nova Floresta deposit) treated with five percent calcitic lime gave greater reactivity when subjected to curing and immersion, while the L-1 soil (Sapé-Mari deposit) treated with five percent of the dolomitic lime it gave greater reactivity value, when the specimens were tested immediately after compaction. In the light of these results, it was possible to offer a qualitative interpretation of the stabilization mechanism of the studied laterized red soils. Finally, a statistical relationship was found between the CBR value and the cone penetration resistance value. This allowed us to propose the cone penetrometer test as an alternative to the CBR test when used in the field.