Document Type : Original Article
Authors
1
Civil Engineering Department, University of Mohaghegh Ardabili, Ardabil, Iran,
2
Ph.D., Civil Engineering Department, University of Mohaghegh Ardabili, Ardabil, Iran,
Abstract
Roller compacted concrete pavement contains conventional concrete components and has differences such as consistency, aggregate gradation, mix design and construction method. In this study, after determination of consistency by Vebe test, compressive, split tensile and flexural strengths were determined at 7, 28 and 90 curing days. Also, the relationships between different strengths were presented at different ages, which is a good match between the relationships obtained in this study and the relationships provided by ACI. Then, in order to reduce the defects of plain concrete and improve the mechanical properties, steel fibers and nanosilica with volume ratios of 0.33%, 0.67% and 1% and weight ratios of 0.5%, 1% and 1.5%, respectively were added to plain RCCP and strengths at different ages were determined. The maximum increase in strengths occurred in samples containing 1% steel fibers and 1% nanosilica which at 28 days compressive, split tensile and flexural strengths increased by 27.2, 94.4 and 102.6%, respectively. The effect of adding steel fibers and nanosilica on flexural strength is greater than compressive and split tensile strengths. The trend of strength change in 7-day and 90-day samples is similar to the behavior of 28-day samples. The addition of steel fibers and nanosilica increases the Vebe time and reduces the consistency of the mixture. Nanosilica by increasing the viscosity of cement paste, reduces the release of cement paste from mortar pores during compaction and reduces the workability. By including steel fibers, the thickness of the pavement can be reduced, as a result, the amount and cost of materials will be reduced and the execution speed will be higher, and the dead load will be reduced, which can be important in structures such as bridges.
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