Experimental evaluation of the durability of cork concrete

Concrete elements used on the exterior of buildings are subjected to cycles of moisture and dryness with changing seasons and different weather conditions. In cold climates, this cyclical action on the concrete may have a considerable influence on its durability because of the aggressive freeze-thaw phenomenon. More compact types of concrete are more sensitive to the freeze-thaw effect, since the expansion of frozen water within it creates great internal stresses. One way to assure higher durability is to introduce a controlled number of voids inside the concrete, to reduce these stresses. Some international standards for concrete, in particular European standard EN 206, prescribe the use of chemicals that produce air bubbles within the concrete. The performance of an alternative method to provide concrete elements with the desired durability has been tested. The introduction of cork granules in concrete admixtures creates soft spots within the concrete, emulating the effect of air bubbles produced by chemical agents. Laboratory tests were performed to compare the performance of different types of concreet when subjected to accelerated aging by freeze-thaw cycles. Standard concrete, cork concrete containing air-entraining chemicals were tested and the results are given in this paper. Copyright © 2008 IAHS.