مهندسی عمران شریف (Nov 2017)
THE MECHANICAL AND DURABILITY CHARACTERISTICS OF ROLLER COMPACTED CONCRETE PAVEMENT (RCCP)
Abstract
In recent years, the asphalt production cost has been increased appreciably. On the other hand, by decreasing the construction projects, the cement industries could not work at full capacity. In order to overcome these problems a considerable attention has been attracted to the development of concrete pavements. This study was thus conducted to investigate the durability and mechanical characteristics of Roller Compacted Concrete Pavements (RCCP).The influence of variation in water content was investigated by using different w/c of 0.33, 0.35 and 0.38. Three different cement contents of 325 $kg/m^3$, 350 $kg/m^3$, and 375 $kg/m^3$ were also made for comparison purposes. A pozzolanic cement concrete and a concrete mixture with 7\% cement replaced by silica fume were also compared to the plain concrete.The concrete mixtures had 28days compressive strengths higher than 35 MPa, surpassing the recommended minimum level of ACI325-10R. Increasing the cement content, in conjunction with decreasing w/c content, led to higher compressive strengths at 7 and 28 days. Silica fume concrete outperformed the other mixtures at 28days. Similar trends were obtained for flexural strength test results.The durability results indicate that by decreasing the w/c content from 0.33 to 0.38, the penetration depth of water was reduced from 10 mm to 14 mm. The lowest penetration depth was observed for the mixtures containing silica fume and the pozzolanic cement. This shows a more tortuous and discontinuous microstructure in these mixtures due to pozzolanic reactions.The salt scaling resistance results indicate that the mixture containing silica fume had higher deicer salt scaling resistance compared to the other mixtures. The mixtures with pozzolanic cement and that with the lowest w/c content (0.33) had also higher resistance against salt scaling compared to the other plain mixtures. Increasing the w/c content significantly influence the salt scaling resistance of the mixtures, leading to lower salt scaling resistance.
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