Repair of a minor bridge in the state of failure with an atypical design using prestressed bridge meshes and bitumen slurry

This article discusses methodological approaches to the repair and maintenance of minor bridges with the atypical design that are in the state of failure, that doesn’t have design documentation, as well as regulatory and methodological documents for the maintenance work organization and technology. Such bridges, although in small numbers, are present on territorial and municipal road networks, for example, in the Orenburg region. The bridge floor turned out to be hydrophobic. Precipitation cannot penetrate under the asphalt concrete layer due to the loosened bitumen presence, meanwhile, the water that was under the asphalt concrete layer during the summer month came out through the asphalt concrete layer pores through pore pressure. A month after the emergency repair work, under the influence of high summer temperature and mechanical load from passing vehicles, the consolidation processes associated with the evaporation of water were completed, and the loosened bitumen turned into a film state. In the limit of a cold wet asphalt mix based on dispersed viscous bitumen, the conventional hot asphalt concretes properties are achieved. Setting smooth, durable, and waterproof coating allows for minimizing the passing traffic dynamic effects, significantly slowing down the destructive processes in the bridge’s bearing elements. For the first time, a minor bridge in the state of failure with an atypical design was repaired by grouting the soil ground around the bridge supports with a liquefied bitumen slurry to a 0.5 m depth, which made it possible to ensure its equal strength. At the same time, the dispersion degree for this project was 1–10 microns due to the bituminous slurry preparation specifics. New is the setting of a hydrophobic double-layered bridge floor without a waterproofing layer from a cold wet asphalt concrete mixture based on dispersed viscous bitumen and the use of a bridge mesh. The possibility of using bitumen-cement-concrete nonshrinking mixtures in the repair of the bridge masonry is shown. The bridge floor geometry was selected for the shockless mode of the existing traffic flow, with the account of the velocity squared of traffic, the bridge floor height, the sum of curvature radii, and the vehicle wheel. The possibility of using bitumen-cement-concrete non-shrinking mixtures in the repair of the masonry of a bridge structure is shown. A new result is also the reinforcing system construction for a bridge floor made of cold wet asphalt concrete based on prestressing of a metal bridge mesh that is flexible with tension in displacement increments.