Abstract

The great impact of durability on concrete performance and service life makes it a serious issue in the recent years. Cracking plays an important role in increasing the mass transport properties of concrete thus decreasing its durability against harsh environmental conditions. Construction defects such as improper consolidation is another factor leading to the unacceptably high rate of concrete deterioration.
In this research, several concrete specimens were manufactured with two different water-cement ratios. The influence of cracking induced by both mechanical and thermal loading on mass transport properties of concrete was studied. Further, the effect of construction practices including over-vibration and insufficient consolidation on concrete properties was investigated. Ultrasonic pulse velocity was applied to identify the presence of internal damage. Water absorption, electrical conductivity and electrical resistivity are the main standard test methods used for durability evaluation.
It was found that water absorption and electrical conductivity of concrete are not significantly affected by the formation of localized bond cracking under short term tensile loading below 80% of the ultimate capacity. However, the well distributed network of shrinkage cracking associated with rapid microwave heating can accelerate the rate of water and chloride ingress through concrete to the large extent. Results also showed that the presence of large, interconnected voids induced by insufficient degree of consolidation has much more destructive influence on concrete microstructure.