Influence of granulometry, cement content, and moisture in the mechanical performance of the cemented crushed stone

Abstract

The Cemented Crushed Stone (C2, as the South African Classification) was widely used on the main high-traffic Brazilian highways in the 1970s and 1980s. However, it presents several limitations for its use in the road work related to the properties of the material and its almost fragile nature, since as soon as the large variations in the tensile strain take place along the loading cycle, critical and accelerated degradation also occur, leading to material fatigue distress. Several factors stand out as probable causes for the intense and rapid process of fatigue, the main ones being: granulometry, cement content, and moisture content. In this way, a study was carried out to analyze the mechanical properties of C2 based on granulometry variation in relation to the cement and moisture content. It was noted that the mixture with the best joint performance was the one with the highest percentage of the sand fraction, highest cement content, and molded below the optimum moisture. Some recommendations were made for the mix design of C2, such as the definition of a granulometric range that considers the analysis of the aggregate large/small ratio in order to obtain a greater gain of maximum dry specific mass, as well as the use of cement contents above 4%, since below that the cementation will be insufficient. In addition, optimized ratios (aggregate + cement + water) should be defined by performing the mechanical analyzes listed in this paper, in order to select the best performance mixture to be applied in the road works.

Solo-Brita em Bases de Pavimentos Flexíveis: Avaliação quando à Fadiga Utilizando o MeDiNa

“…Para tal, é substancial, em um dimensionamento empírico-mecanicista, compreender a deformabilidade dos materiais que compõem a estrutura do pavimento (Soares et al, 2009;Bernucci et al, 2010;Barros et al, 2019). Outro fator preponderante é compreender como as relações tensão-deformação de cada material (Prado et al, 2020), advindas de ensaios de módulo de resiliência (MR) e deformação permanente (DP), influenciam no comportamento das misturas dependentes dos estados de tensões aplicados em ambos os ensaios. Estas propriedades foram consideradas na concepção de um novo método de dimensionamento de pavimentos flexíveis no Brasil, denominado Método de Dimensionamento Nacional de Pavimentos (MeDiNa).…”