Journal of Structural and Construction Engineering

Journal of Structural and Construction Engineering

Investigating the effect of ambient temperature on the mechanical characteristics of high-strength concrete containing steel fibers and polypropylene under wet and dry cycles and water containing magnesium sulfate

Document Type : Original Article

Authors
1 Ph.D Candidate, Department of Civil Engineering, Qazvin Branch, Azad University, Qazvin, Iran
2 Associate Professor, Department of Technical and Engineering, Imam Khomeini University, Qazvin, Iran
Abstract
Harmful environmental conditions in the Persian Gulf, such as temperature and sulfates, cause extensive damage to concrete structures. One of the factors that greatly affect the destruction of these structures is the amount of harmful factors in the water and the number of times these structures are exposed to water and ambient heat. Therefore, the present study has attempted to do this study, considering the lack of a study that has clearly examined the mechanical characteristics of fiber reinforced concrete under the mentioned conditions. In this research, high-strength concrete without fibers and high-strength concrete with PP, ST fibers and PP-ST hybrid fibers were used. Destructive environmental conditions of this study are simulated wet and dry cycles in 60, 120, 180, 240 and 360 cycles at ambient temperature and at 40 degrees Celsius under blowing heat to the samples and compressive, tensile and shrinkage tests have been used. Among the results of this study, there is a faster growth of the initial compressive and tensile strength in conditions at 40 degrees Celsius, which is because the dry process is faster, so that it affects the moisture transfer of concrete, and the wetting process that occurs after that, accelerates the ions and solutions into the concrete and deepens the depth of penetration and accelerates the production of ettringite. In the strength drop stage, HS-ST-PP, HS-ST and HS-PP concretes show the lowest compressive strength drop, respectively. While at a temperature of 40 degrees Celsius, HS-PP concrete shows a better behavior than HS-ST concrete, which is due to a lot of rusting and corrosion of steel fibers in these condition.
Keywords

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