Analysis of Cracking Mechanisms in Concrete Pavements and Related Recommendations For Pavement Construction

In addition to the stresses caused by traffic loads concrete highway pavements may be subjected to considerable stresses due to environmental action effects and other related damaging mechanisms such as early age shrinkage, loss or absorption of moisture, temperature induced strain gradients and in some instances also alkali-silicareactions. Due to various and complex interactions of these processes no conclusive understanding of the damaging mechanisms caused by such actions has been gained so far. Therefore, a comprehensive numerical study has been carried out in order to quantify the developing stresses and to analyse the cracking behaviour of concrete pavements. The numerical investigation comprises an extensive parameter analysis, taking into account various material characteristics, environmental conditions and the effects of the type of pavement construction. The major results obtained are presented in this paper. It could be shown clearly under which conditions shrinkage may lead to surface cracking, which type of cracking may be caused by temperature shocks and how an alkali-silica-reaction of the concrete may contribute to the probability of cracking. In addition, the individual contributions of the various damaging effects have been quantified. This information was used to establish some principles to be followed in the construction of concrete pavements in order to enhance the durability and the life time of such structures.