Influence of Alkali-Silica Reactions on Cracking in Concrete Pavements

In the last few years cracking in concrete pavements was observed in several highway sections in some regions of Germany. Within the scope of extensive investigations no definite single cause of cracking could be observed in the majority of these cases. Besides incremental load-induced stresses by increasing heavy traffic, within this scope especially load-independent stresses due to hygral and thermal changes are of relevance. Several investigations additionally substantiate reaction products of an alkali silica reaction (ASR). Because of this multiplicity of potential causes for cracking it has not been definitely clarified up to now to which extent especially the ASR contributes to cracking in concrete pavements. Rather it seems that superposition and/or interactions of different mechanisms are responsible.