Influence of urban heat island effect on sulphate attack on concrete

To study the influence of urban heat island effect on sulphate attack on concrete, three environments are designed to simulate both sulphate attack underground and crystallisation attack on the ground surface. Experiments last for 1 year and then all specimens are taken out to conduct macro-observations and micro-observations. Results indicate the following: after attack, the micro-structural change of concrete is in accord with the macro-mechanical behaviour; under the influence of urban heat island effect, the visual degradation mainly induced by ettringite is much more serious and the crystallisation attack mainly induced by thenardite crystal is extended to greater range, and therefore the compressive strength is decreased more obviously. The degradation is particularly prominent for C20 concrete, this should be paid more attention, because in China, C20 concrete was often adopted by relatively early building foundation and underground pipeline. This research will provide good basis for further putting forward repair techniques to the attacked concrete material. © W. S. Maney & Son Ltd 2015.