: 183-186
Lviv Polytechnic National University
Lviv Polytechnic National University, Department of highways and bridges
Lviv Polytechnic National University, department of Highways and Bridges

Today, all the more significant share in the network of highways is occupied by roads with Portland cement concrete pavements. Materials stabilized with Portland cement are increasingly used under rigid pavements, therefore the problem of correct thickness of the basis is of a great importance. Soil cement and gravel-cement bases have considerable dispersion, which leads to a significant increase in the bearing capacity of concrete pavement. In the article the results of experimental tests of models of concrete pavements on the sandcement basis of different stiffness in the laboratory conditions with static and vibrodynamic loading are given. For this purpose, a testing bench and experimental site of the pavement model at scale 1:3 was constructed at the laboratory of the Department of Highways and Bridges in Lviv Polytechnic National University. Test site consisted of six slabs measuring 2x1 m, connected by type of compression joints. For the two middle slabs the design was constantly changing. The thickness of the concrete slabs was 5, 7 and 9 cm, and the thickness of the sandcement bases was 0, 5 and 10 cm. Regression equations are presented according to the results of static tests, as well as vibration-dynamical endurance tests, that characterize the dependence of deflections and stresses in the most intense sections of the pavement slabs and the number of cycles of repeated dynamic loads on the thickness of the slabs and the base. Dependences of deflections and stresses on the action of a static load on the thickness of the plates and foundations were sought in the form of first-order regression equations. It is established that the bearing capacity of 1 cm of concrete slab is equivalent to 1.8–2.0 cm thick sand-cement base. Such a conclusion follows from the analysis of the coefficients of the obtained regression equations. Thus, coefficients at the indexes of the thickness of concrete slabs are 1.8–2.0 times larger than the similar coefficients at the indexes of the slab thickness of the sand-cement bases. Such bearing capacity of rigid bases can be observed only for an optimal ratio between the thickness of the base and the pavement, which is 0.8-0.9.

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