Expansão por umidade (EPU) é o aumento das dimensões dos materiais cerâmicos em virtude da adsorção de água. A EPU geralmente ocorre lentamente e é relativamente pequena, mas, mesmo assim, pode comprometer a aderência das placas cerâmicas ao contrapiso, levar ao gretamento do vidrado e conduzir ao aparecimento de trincas em tijolos. Neste trabalho empregaram-se massas incorporadas com resíduos de caulim e de granito objetivando estudar a EPU de revestimentos cerâmicos. As matérias-primas foram beneficiadas e submetidas às caracterizações físicas e mineralógicas através de ensaios de análise granulométrica por difração a laser, análise química, análise termodiferencial, termogravimétrica e difração de raios X. Os resultados mostraram que os resíduos de caulim e de granito podem ser utilizados como matéria-prima cerâmica alternativa, pois apresentam características similares às matérias-primas cerâmicas convencionais, permitindo a obtenção de peças com resultados de EPU satisfatórios quando comparado ao valor limite de 0,6 mm/m (0,06%) proposto pela ABNT para revestimentos cerâmicos, notadamente em composições com teores de até 20% de resíduos, a temperaturas superiores a 1000 ºC.
Warm mixtures are an essential alternative for paving as they minimize costs and environmental impacts, and their performance is similar to hot mixtures. This research evaluated the effect of adding linseed oil obtained from Linum usitatissimum in the contents of 1, 2, 3, 4, 5, and 6% by weight on the physical and rheological properties of the asphalt binder. The asphalt binder was evaluated through tests of penetration, softening point, rotational viscosity, performance grade (PG); these tests were performed before and after the short-term aging procedure; multiple stress creep and recovery (MSCR), and linear amplitude sweep (LAS). It has been verified that the mixing temperature could be reduced by up to 15 °C for the 6% linseed oil content, but it was lost in terms of performance, level of supported traffic, and fatigue life. In the so-called ideal content found, 4% linseed oil, there is a reduction in the mixing temperature of around 10 °C, as well as a maximum temperature of PG, 58 °C, it reduces by only one step compared to the pure binder, 64 °C, in addition to presenting the secondlongest fatigue life of the grades studied, being classified as ideal for standard traffic by the MSCR test. Linseed oil proved to be an excellent green alternative for the production of warm mixtures.
This paper investigated the rheological performance of the combination of ethylene methyl acrylate and glycidyl methacrylate—EMA-GMA (reactive polymer)—and high-density polyethylene (HDPE) associated with polyphosphoric acid (PPA116%) in the modification of an asphalt binder (PG 64-XX). Tests such as performance grade (PG), multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and master curve vary the EMA-GMA and PPA116% contents to obtain an ideal composition to provide a high-performance asphalt binder and thus compare with an unmodified asphalt binder and a styrene-butadiene-styrene (SBS) modified asphalt binder. The results showed that the asphalt binder stiffness improved as the EMA-GMA and PPA116% content increased. The PG temperature increased with the addition of PPA116% content in the asphalt binder samples, being most significant with the use of 1.8% of EMA-GMA. The addition of the combined polymers decreased the susceptibility to rut and improved the elastic recovery of the asphalt binder PG 64-XX, but only the samples with 1.8% EMA-GMA showed higher elastic recovery than the SBS-modified binder. PPA116% provided benefits in damage resistance at all strain levels; however, more was observed in samples subject to minor strains. The incorporation of 1.8% EMA-GMA, 0.3% HDPE, and 0.5% PPA116% was the one that presented the most improvements, without presenting gelation, in the performance of the asphalt binder in relation to stiffness and elasticity with increasing temperature. Thus, the use of these polymers in this composition can be a good alternative to regions with high temperatures, such as the northeast region of Brazil.
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