Introduction. Bridges are one of the most important components of transport infrastructure. And transport structures are built of complex structures, and the cost of their operation is high. In the last period, the traffic intensity and weight of vehicles on the roads of Ukraine have significantly increased. Ensuring reliable and trouble-free operation is a priority, complex and responsible task.
Problem statement. After the installation of a cement-concrete surface on the bridge on Km 159+267 of the H – 31 Dnipro – Tsarichanka – Kobelaki – Reshetilovka road, cracks were found on the cement-concrete surface across the entire passage after some time. Oblique and transverse cracks soon appeared in the surface on both adjacent bridges (separate bridges for different directions of movement). The opening of cracks reached 1 mm.
Materials and methods. On the bridge at Km 159+267, an experimental design was applied — a cement-concrete coating made of concrete of class B40.
It provides for the device of dense waterproof concrete of the roadway slab, 110 mm thick, made of monolithic concrete of Class B40 F300 W12 (C32/40, XF4, C1 0,20 according to DSTU B V.2.7‑176:2008, crushed stone fraction 5–10 mm), after the device of a monolithic slab with a thickness of 200 mm, combining the beams of the superstructure.
To study damaged structures, methods for measuring the opening of cracks using probes and tape measures were used. To determine the adhesion of the coating to a monolithic slab, samples were taken – round cores using a core collector. The strength of the concrete was measured with a sclerometer.
Results. As a result of the conducted research, the lack of adhesion of the cement-concrete coating to the monolithic slab of the bridge was revealed.
To achieve high performance, it is necessary to disassemble the damaged cement-concrete surface and install a new coating to eliminate defects in the bridge surface on km 159+267 of the H-31 highway.
Conclusions. Studies have shown that more and more new cracks appear in the cement-concrete coating, and the opening of old ones increases. The cause of cracks is shrinkage of concrete. Since concrete shrinkage can last up to 1.5 years, even more cracks should have been expected to appear. It also turned out that the cement-concrete coating does not adhere to the monolithic slab of the superstructure.
Given the above reasons, it is impractical to repair individual cracks.
To achieve high performance, it is necessary to disassemble the damaged cement-concrete coating and install a new one. Taking into account the capabilities of the contractor, the construction of the bridge bed and asphalt concrete pavement was developed.
