A PRELIMINARY RESEARCH ON USING CORE RING METHOD TO MEASURE RESIDUAL STRESS IN CONCRETE PAVEMENT SURFACE

In the development of concrete strength, the cementitious materials change volume in response to moisture variations, temperature variations and chemical reactions. If these volume changes are restrained, residual stress will develop and result in micro cracking and cracking. Many models are developed to predict the residual stress, but their accuracies are not verified yet. Measuring residual stress accurately is very helpful to pavement design and evaluation. Similar to the hole drilling strain gage (HDSG) method which is often used in metal structures for measuring residual stress, the core ring strain gage (CRSG) method is developed to measure residual stress in concrete structures. The concrete is made up of pastes and aggregates, so the feasibility of this method needs to be investigated. The preliminary tests of CRSG method were conducted by Federal Aviation Administration’s (FAA) National Airport Pavement Test Facility (NAPTF) in 2007. In this paper the finite element (FE) model is developed to simulate the hole and core ring drilling. For the hole drilling in a plate, a closed form solution is derived, thus the FE model is validated through a comparison between FEM’s results and the closed form solution. A comparison between FE model’s results and FAA’s test results demonstrates the feasibility of CRSG method in concrete.