Análise dos efeitos da adição de cal e de cimento para estabilização de solos

Abstract

Soil is a material originated from the deterioration of rocks, through various intemperate actions that occur in nature. For this reason, the soils present distinct compositions and, consequently, peculiar physical characteristics in different regions of the planet. Most, if not all, of the construction industry will have to deal at some point with the local soil, that is, with its characteristics and properties. Most of the time, the soil properties do not meet the design requirements, causing them to look for alternatives to solve the problem. Thus, it is of great importance to carry out the preliminary study of the soil characteristics. Because it is a more economical and environmentally friendly solution, soil stabilization is the most used process to solve the problem. Stabilization can be mechanical - compaction, or chemical - addition of chemical additives such as cement and lime. The present study aimed to analyze the effects of compaction energy and additive content on the unconfined compressive strength of soil-cement and soil-lime mixtures. For this analysis, some soil samples were molded with contents of 3%, 5%, 7% and 9%, compacted at the intermediate energy. The results were compared to the results of Sales et al. (21017) for the same contents of additives, compacted at the standard energy. The intermediate Proctor results were 1,62 g/cm³ for the maximum dry unit weight and 20,5% for the optimum moisture. The samples compacted on intermediate energy presented a better result than standard energy. Comparing this research results with Sales et al. (2017), it was noted that cement treatment produced higher unconfined compressive strength than lime. An 2k factorial experimental design of the results was also developed. Thus, two levels, minimum and maximum, were considered for the variables. The aim of the analysis was to adjust the data to a model so that it was possible to predict the behavior of the mixture. The model generated for soil-cement presented problems in the data residues, indicating that the adjustment was not feasible. The soil-lime presented a good fit of the second-order model found. The following equation was defined:Y (MPa) = 0,86225 + 0,15317. (TA/3% − 2) + 0,16825. (EC/0,055 − 28, 45 ̅̅̅̅) − 0,07083. (TA/3% − 2) . (EC/0,055 − 28, 45 ̅̅̅̅), where Y represents the unconfined compressive strength, TA is the additive content and EC is the maximum dry unit weight. The equation presented results compatible with the values found in the laboratory, validating the model. Thus, from the equation, a response surface was generated for soil-lime