Ein Beitrag zur Kerbtiefe bei Querscheinfugen in Betonfahrbahnen

The sawcut depth of transverse contraction joints in jointed plain concrete pavements affects the crack in-duction in early age concrete and the states of stress around the contraction joints caused by temperature during operation. With the results of temperature measurements in concrete pavements during cement hydration, the development functions for the modulus of elasticity, the basic creep index and the centric tensile strength of a young street concrete resulting from laboratory tests, the unsteady zero-stress temperature conditions were investigated in numerical model calculations and, by means of semi-probabilistic considerations, the tear behavior when the sawcut depth was varied. The reduction of the sawcut depth from 25 % to 30 % according to design regulations to 10 % of the concrete pavement thickness does not affect the first cracking negatively if material parameters scatter little and the concrete road is constructed with great dimensional accuracy. During operation, the reduced sawcut depth (10 % of the concrete pavement thickness) causes an up to 50 times lower heat damage probability with the temperature lo-ad of a hot summer day according to the numerical model calculations carried out with evaluation using a three-dimensional failure model and semi-probabilistic observation.

Automated summary

The sawcut depth of transverse contraction joints in jointed plain concrete pavements affects the crack induction in early age concrete and the states of stress around the contraction joints caused by temperature during operation. The reduction of the sawcut depth can lower the heat damage probability.