نوع مقاله : علمی - پژوهشی
1 دانشجوی دکترا، دانشکده فنی و مهندسی، دانشگاه بینالمللی امام خمینی (ره)، قزوین، ایران
2 دکتری، دانشکده فنی و مهندسی، دانشگاه بینالمللی امام خمینی (ره)، قزوین، ایران
3 استاد، دانشکده فنی و مهندسی، دانشگاه بینالمللی امام خمینی (ره)، قزوین، ایران
عنوان مقاله [English]
The concrete surface is the most significant part as it is in direct contact with the outside world. Therefore, increasing the surface strength of concrete could reduce the absorption of harmful substances into the concrete. Permeability and surface strength can be regarded as factors that affect the durability and service life of a concrete structure. As a result, a concrete structure with the desired surface strength and low permeability is of paramount importance. Hence, this study attempted to measure the surface strength and permeability of concrete through “twist-off” and “Cylindrical Chamber” tests under temperature cycling. Relations between the surface strength and permeability of concrete samples were obtained. In addition, a linear function was used to estimate the relation between penetration depth and volume with high precision. According to the twist-off test results, extending the curing age of plain concrete would increase the surface strength; the surface strength at the age of 120 days exceeds that of 7 days by approximately 42%. However, when temperature cycling was performed on the samples, the surface strength of the concrete caused by the twist-off Test decreased. Further, results from the permeability tests using a cylindrical chamber indicate that temperature changes have a negative influence on the permeability and penetration depth in concrete samples. The permeability and penetration depth of concrete under temperature cycling caused an 8-fold and 3-fold increase after 120 days, respectively. According to the results of the study, moderate temperature cycles significantly affect permeability and penetration depth.