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[pt] Este trabalho apresenta um estudo técnico experimental sobre a utilização de borracha moída de pneu (BMP) como adição, juntamente com cimento Portland à brita graduada simples (BGS), no intuito de avaliar a aplicabilidade desse material em camadas de base de pavimentos rodoviários. Como resultado obtémse uma BGTC - Brita graduada tratada com cimento, com adição de BMP. O principal objetivo da adição de borracha na BGTC é reduzir o fissuramento, que é um problema comum em bases cimentadas. Para melhor comparação dos resultados das misturas com adições de borracha foi realizada uma mistura de BGTC sem adições, a qual foi tratada como mistura padrão neste estudo, com 3 por cento, 4 por cento e 5 por cento de cimento. O agregado granítico selecionado para esta pesquisa é proveniente de jazida situada no município de Cariacica/ES e foi escolhido por ter apresentado bom desempenho nos ensaios de caracterização. A partir da análise granulométrica realizada na borracha, selecionou-se para esse estudo a fração passante na peneira de 2,38mm e retida na peneira de 1,19 mm. Foram estuadas as seguintes porcentagens de adição de BMP: 0,5 por cento, 1,0 por cento, 1,5 por cento, 2,5 por cento, 3,5 por cento e 4,5 por cento. As amostras foram submetidas a ensaios de compactação, compressão simples, compressão diametral, triaxial de cargas repetidas e microscopia eletrônica de varredura. Os ensaios de compressão simples foram realizados com tempos de cura de 7, 28 e 56 dias. Os ensaios de compressão diametral foram realizados com tempos de cura de 28 e 56 dias. Os ensaios triaxiais de carga repetida foram realizados com tempo de cura de 56 dias. Os resultados obtidos foram satisfatórios, sendo dependentes do teor de BMP utilizados e do tempo de cura. Dentre as composições de BMP estudadas, a que apresentou o melhor comportamento foi a que possuia adição de 1,5 por cento de borracha e 56 dias de cura. Esta adição apesar de reduzir a RCS e a RTCD em 30 por cento e 28 por cento respectivamente, proporcionou melhoria no comportamento resiliente e menor perda de resistência na região pós pico perante o ensaio de RCS. Tal fato ressalta o emprego positivo de borracha de pneu triturada em camadas de base de pavimentos rodoviários, tanto sob a ótica da engenharia de pavimentos quanto em relação a questões ambientais e econômicas. / [en] This work presents a technical and experimental study on the use of tire rubber as an addition, together with Portland cement, to a simple graded gravel, in order to evaluate the applicability of this material in the base layers of road pavements. As a result, cement-treated graded gravel with the addition of rubber is obtained. The main objective of the addition of rubber is to reduce cracking, which is a common problem in cemented bases. A standard mixture of cement-treated graded gravel was carried out for better comparison between the mixtures with additions of 3 percent, 4 percent and 5 percent of cement. The granitic aggregate selected for this research came from the municipality of Cariacica/ES and was selected because it presented an appropriate performance in the characterization tests. From the granulometric analysis performed on this material, the fraction passing the sieve 2,38 mm and retained in the sieve 1,19 mm, was selected for this study. In this study were selected 0,5 percent, 1,0 percent, 1,5 percent, 2,5 percent, 3,5 percent and 4,5 percent additions of rubber. The blends were subjected to compaction, direct compression, split tensile, cyclic triaxial and scanning electron microscope tests. Direct compression tests were performed with cure times of 7, 28 and 56 days. Split tensile tests were performed with curing time of 28 and 56 days. Cyclic triaxial tests were performed with curing time os 56 days. The results were satisfactory, being dependent on the content of rubber and the curing time. Among the blends that were analyzed, 1,5 percent of addition and 56 days of curing time leaded to the best results. Despite the reduction of 30 percent and 28 percent in the compression and tensile resistances, this amount of rubber addition provided a better resilient behavior and a higher post pick resistance in the compression test. This fact highlights the positive use of tire rubber in pavement base layers, not only from the standpoint of pavement engineering, but promoting gains of sustainability and economy as well.

Full-depth reclamation (FDR) in conjunction with cement stabilization is an established practice for rehabilitating deteriorating asphalt roads. Conventionally, FDR uses dry cement powder applied with a pneumatic spreader, creating undesirable fugitive cement dust. The cement dust poses a nuisance and, when inhaled, a health threat. Consequently, FDR in conjunction with conventional cement stabilization cannot generally be used in urban areas. To solve the problem of fugitive cement dust, the use of cement slurry, prepared by combining cement powder and water, has been proposed to allow cement stabilization to be utilized in urban areas. However, using cement slurry introduces several factors not associated with using dry cement that may affect road base strength, dry density (DD), and moisture content (MC). The objectives of this research were to 1) identify construction-related factors that influence the strength of road base treated with cement slurry in conjunction with FDR and quantify the effects of these factors and 2) compare the strength of road base treated with cement slurry with that of road base treated with dry cement. To achieve the research objectives, road base taken from an FDR project was subjected to extensive full-factorial laboratory testing. The 7-day unconfined compressive strength (UCS), DD, and MC were measured as dependent variables, while independent variables included cement content; slurry water batching temperature; cement slurry aging temperature; cement slurry aging time; presence of a set-retarding, water-reducing admixture; and aggregate-slurry mixing time. This research suggests that, when road base is stabilized with cement slurry in conjunction with FDR, the slurry water batching temperature; haul time; environmental temperature; and presence of a set-retarding, water-reducing admixture will not significantly affect the strength of CTB, provided that those factors fall within the limits explored in this research and are applied to a road base with similar properties. Cement content and cement-aggregate mixing time are positively correlated with the strength of CTB regardless of cement form. Additionally, using cement slurry will result in slightly lower strength values than using dry cement.