Evaluation of crack formation and spacing in continuously reinforced concrete pavements using small scale laboratory experiments and numerical modeling

A major concern in the design of continuously reinforced concrete pavements (CRCP) is to control undesirable cracks. Despite the efforts to establish an ideal percentage for the reinforcing steel, unpredictable cracks are often present in CRCP. This has resulted in reduction and in some cases elimination of CRCP as an option, where asphaltic concrete (AC) or jointed concrete pavements (doweled or undoweled) have been constructed instead.; The main objective of this study was to develop an innovative steel arrangement in CRCP. The potential for development and spacing of the cracks was determined by means of experimental, analytical and numerical studies. The study demonstrates the potential for elimination of all joints when the recommended steel arrangement is followed.; In the first phase of the study a comprehensive review of small scale concrete (microconcrete) and its applicability in the pavement industry was conducted. The literature survey and subsequent laboratory experiments resulted in several models for determination of the microconcrete material properties.; Once the microconcrete material properties and behavior were determined, the experimental phase of the study for pavement analysis was begun. In this phase, model slabs (12:1 actual:model) were prepared with various arrangements (angles) of especially fabricated small scale reinforcements. A testing scheme was devised to apply uniaxial tensile loading to the model slabs at a desired rate, simulating the shrinkage phenomenon in concrete. In addition to measuring the overall load-displacement response, variation of axial strain within the model slab was measured. Then, a sensitivity analysis for the percentage of steel and the angle of inclination of rebars placed in the slabs was conducted.; The experimental results were compared with analytical and numerical results. In the initial numerical studies a two-dimensional model of the slabs tested experimentally was developed. This was accomplished by using a commercially available finite difference software, named FLAC.; Subsequently, a three-dimensional finite element model of a continuously reinforced concrete (CRC) pavement was developed. This was done by using a general purpose finite element software named ABAQUS. The advantage of the inclined reinforcement to the ordinary longitudinal ones was evaluated and demonstrated. Finally the study investigated the potential for elimination of all joints when the recommended steel arrangement is followed.