Оценка предела прочности при сжатии в самоуплотняющемся бетоне, подверженному циклическому замораживанию и оттаиванию, с использованием ультразвукового импульсного метода

Abstract

The development and use of self-consolidating concrete (SCC) considerably increased in the last decade. This work aims to evaluate the effect of using air-entraining admixture (AEA) on the compressive strength of SCC subjected to freeze-thaw (F-T) cycles. For comparison purposes, six mixtures were prepared with fixed powder content of 580 kg/m3 and sorted into two categories of unmodified and air-entrained SCC mixtures. For each category, the water-to-cement ratio (w/c) varied at 0.45, 0.5, and 0.56. The corresponding compressive strength and ultrasonic pulse velocity (UPV) measurements were carried out on samples before and after being subjected to 400 F-T cycles. Test results demonstrated that AEA enhanced the performance of SCC, particularly at lower rates of w/c. Air void characteristics records validate the enhanced performance for air-entrained SCC, given the air void system that accommodated the disruptive expansive stresses resulting from F-T cycles. Furthermore, the residual compressive strength of SCC can be accurately estimated by using UPV measurements.