Document Type : Original Article
Authors
1
Professor, Civil Engineering Faculty. Imam Khomeini International University. Qazvin. Iran
2
Ph.D. Structural, Head of Research Group of Natural Disaster Research Institute,, Tehran. Iran.
3
P.h.D. Student, Civil Engineering Faculty, Imam Khomeini International University, Qazvin, Iran
10.22065/jsce.2023.392852.3095
Abstract
The penetration of water into concrete can reduce the durability and reliability of concrete. Especially, successive increase and decrease in temperature causes negative changes on the physical and chemical characteristics of concrete, and this issue can reduce the performance of concrete against water penetration. Therefore, it is necessary to investigate the effects of temperature cycles on the surface resistance of concrete and the amount of penetration volume and depth of water penetration into concrete. Also, considering that according to international standards, to measure the permeability of concrete, a concrete sample must be broken, so a new test is needed to measure the volume of water penetration into concrete without breaking the sample. Before starting the test; First, the concrete samples were placed in the oven for a certain time and temperature, and then they were taken out of the oven and kept at room temperature for 16 hours. In this method, a cycle of temperature changes is completed. With the completion of the desired number of cycles, the samples are removed from this process and subjected to permeability and friction transfer tests, and finally, the sample is divided in two half by a compression jack and its wetted surface is measured to obtain the depth of penetration. has been According to the results, by comparing the volume of water infiltration into concrete in normal samples with the samples placed in different temperature cycles, it is observed that the cycles of 20, 40, 140 and 160 respectively increase the volume of water infiltration. It has been increased to concrete by 2.2, 4.3, 14.9 and 16.8. . In addition, by applying the above cycles, the strength obtained from the friction transfer test at the age of 120 days has decreased by 2.4, 6, 65, and 79 percent, respectively, compared to normal concrete.
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