Considering the influence safety factor for frost resistance when calculating pavement

Abstract

The regularities established in the course of researches show that coefficients of frost resistance of asphalt concretes to various extent decrease under the influence of cyclic freezes-thaws. This work allows us to recommend the use of additional coefficients of frost resistance in the design of new roads with layers of non-rigid pavement.

Under experimental conditions, the road surface is exposed to cyclic freezing and thawing (FTC). Today, the topic of asphalt concrete FTC is relevant. Many scientists in different countries are dealing with this problem.

According to the literature, the layer of asphalt concrete can lose 40 - 80% of the load-bearing capacity. This property is associated with a decrease in the modulus of elasticity of the layer over time. In order to prevent a critical effect of the layer on the load-bearing capacity of pavement, you can use the various methods described in the article.

To determine the required index of frost resistance, the road structure with VBN B.2.3-218-186-2004 "Non-rigid road clothing" is considered. The modulus of elasticity of asphalt concrete of the upper layers is taken from this construction and the change of strength coefficients is calculated taking into account the change of modules under the action of cyclic freezing-thawing.

Technical and economic calculation shows that to compensate for the loss of load-bearing capacity of pavement from FTC it is advisable to use asphalt concrete on bitumen of high consistency and proved, based on the calculation of strength factors, that the use of modified bitumen is more effective than traditional bitumen. The article considers the need to use an additional coefficient of frost resistance of asphalt concrete during the design of the road on the example of the road structure with VBN B.2.3-218-186-2004 "Non-rigid road clothing"