Investigation of Crack Width Development in CRCP

The traffic volume on German motorways increased steadily and this trend is expected to continue in the future. To guarantee mobility in the future and reduce the national economic consequential costs, road construction with a maximum service life and a minimum of necessary maintenance are needed. Rigid road pavements with continuous reinforced concrete pavement (CRCP) are extremely durable in terms of use and maintenance. The behavior of CRCP is influenced by a number of specific characteristics such as the thickness and the quality of the concrete, the design and amount of the longitudinal and transversal reinforcement, the base layer and the environmental conditions at the time of construction and during service life. These aspects influence the crack pattern, crack distance and crack widths. Crack width initially depends on the temperature of construction (zero-stress temperature of the concrete). The ultimate shrinkage of the concrete also controls crack width over time. Thus, anything that will reduce shrinkage will be desirable for CRCP (AASHTO, 2008). Identified positive crack pattern are one important indicator of positive long-term behavior. From 1997 to today, a total of 8 sections with many variations have been built in Germany. As part of a research project, the RWTH University of Aachen and the German Federal Highway Research Institute (BASt) are investigating these sections with CRCP with and without an asphalt surface course in Germany, and Poland and compare it to the Belgium standard constructions. The aim is to evaluate the different designs in the sections in terms of their behavior in service, to quantify achievable service lives, necessary maintenance and availability. To increase the service life of CRCP and to protect the reinforcements of de-icing salt, the crack width must be kept as narrow as possible. In addition to in situ measurements on the test tracks, laser scanners were also used to investigate the crack width development on the drilling cores. The Project is financed by the German Federal Ministry of Transport and digital Infrastructure (BMVI)