Geosynthetic materials properties analysis suitable for controlling reflective cracks in asphalt concrete

Abstract

Reflective cracks appearing in the new asphalt concrete layer laid during reconstruction over the existing concrete or asphalt concrete pavement is the main cause of premature highways failure. Cracks of this type appear over defects in the old pavement and grow through the new pavement under the influence of vehicle loads and fluctuations in the temperature field. One of the common ways to combat reflective cracks is the use of an intermediate reinforcing layer made of special geosynthetic material, redistributing part of the loads. The paper proposes a multilayer pavement structural model and a temperature field change model based on the design documentation of the M-11 «Neva» highway and data from the temperature monitoring station. Temperature stresses сalculation arising in reinforced asphalt concrete layers in the existing crack vicinity of the old pavement is performed by the finite element method using the approximate method of Hills and Brien, reducing the calculation to the sequence of solving problems of linear elasticity theory. The dependencies of asphalt concrete rigidity modulus on temperature and time of load action are calculated on the basis of penetrative index and the binder softening temperature, taking into account the inevitable aging of the binder during paving and pavement operation. It is shown that significant reduction of dangerous tensile stresses in asphalt concrete is possible at reinforcement with geogrids with maximum tensile strength not lower than 100 kN/m, made on the basis of high-modulus glass or carbon fibers, under condition of joint work of asphalt concrete and reinforcing layers in the absence of mutual slippage.