About the main causes of cracks in-situ cement concrete pavements in joints

Abstract

In recent years, the use of concrete (cement concrete) bases and coatings of roads and industrial sites has begun to revive in road construction. Employees of the Department of «roads» BGIT together with students for several years under surveillance for cracks in the monolithic cement concrete layers of coatings. The article presents the results of field surveys of cement concrete coatings of highways of the Bryansk region and industrial sites in order to identify the causes of cracks in the expansion joints. We have examined the sections of roads with cement concrete coating on some plates near the seam and found the formed transverse cracks. They were located mainly along the seam, the maximum opening width reached 5 mm. the Maximum distance from the seam 30 cm. Cracks along the seam were located unevenly and had a diverse shape. We have also calculated several variants of pavement with cement concrete coating on different bases. As a result of the survey were tested: the coefficient of compaction of the base material, the compressive strength of concrete in the coating plates, the technology of works on the device of coatings and expansion joints in them, as well as the control of the project materials submitted by the design organization, including the project of works. In conclusion, the following main causes of cracks in monolithic cement concrete coatings of roads and industrial sites can be identified: errors made in the calculation and design of the pavement structure; errors made in the calculation of the length of the plates, the appointment of reinforcing bars in the seams; errors in the construction of cement concrete pavement construction organization (if device transverse control joints and expansion joints in compression, buckling and longitudinal). The study material is generalized, road and construction organizations are given recommendations for the elimination of cracks, some measures to prevent their occurrence are indicated.