Modelling negative thermomechanical effects in reinforced road structures with thermoelastic incompatibility of coating and reinforcement materials

Abstract

The phenomena of the formation of local defects and cracks in asphalt concrete pavements of roads and bridges are most often observed in climatic zones with large temperature differences during their seasonal and daily changes. To a large extent, this is due to the heterogeneity of the thermomechanical properties of the materials of the coating layers and the base. To prevent these phenomena, reinforcing rods and meshes are introduced into the coating structure. In this work, using the theory of thermoelasticity, it is shown by the method of mathematical modelling that in cases of incompatibility of the thermomechanical characteristics of asphalt concrete materials and reinforcement, additional localized thermal stresses arise in its small vicinity, which, even at moderate temperatures, can reach critical values and lead to local defects and cracks. Since these defects are latent, they cannot always be detected in practice. The presented results of analytic calculation validated these conclusions. They can be used in both road building and composite design.

Theoretical modelling of the effect of thermal delamination of an asphalt concrete pavement from a rigid foundation of a road or bridge

“…As the experience of operation of roads and bridges in countries with large temperature fluctuations shows, the most intense manifestations of the effects of cracking, local destruction and general degradation of asphalt concrete materials occur in their structures in winter and summer seasons [1,5,8,11]. Under conditions of frequent temperature changes in heterogeneous asphalt concrete structures with thermomechanical incompatibility of their components, these defects can contribute to their accelerated aging.…”

“…Among the most common phenomena in practice, accompanied by delamination, subsequent cracking and destruction of the asphalt concrete pavement on a rigid (cement concrete or metal) base of a road or bridge, is the effect of concentration of shear thermal stresses between the pavement and the base in the edge zones of the structure [2,3]. They are caused by the fact that, as a rule, the coefficients of linear thermal expansion (CLTE) of coating 1 and base 2 (Fig.…”

“…They are caused by the fact that, as a rule, the coefficients of linear thermal expansion (CLTE) of coating 1 and base 2 (Fig. 1) have different values (1)  and (2)  , which contributes to the occurrence of incompatible shrinkages and expansions in them [6,9,12,14,15]. The disadvantage of attempts to strengthen the structure in these places by increasing the thickness of coating 1 or its modulus of elasticity is that, as shown by calculations [1][2][3], this only leads to negative consequencesa localized increase in shear thermal stresses in the edge zones [1,15].…”

“…1) have different values (1)  and (2)  , which contributes to the occurrence of incompatible shrinkages and expansions in them [6,9,12,14,15]. The disadvantage of attempts to strengthen the structure in these places by increasing the thickness of coating 1 or its modulus of elasticity is that, as shown by calculations [1][2][3], this only leads to negative consequencesa localized increase in shear thermal stresses in the edge zones [1,15]. It is shown below that a decrease in the concentration of high-gradient tangential thermal stresses and prevention of the delamination effect can be achieved by linearly varying thinning of the upper layer in the peripheral areas.…”

“…A clear example of the occurrence of shear thermal stresses in layered structures with a change in temperature T is a bimetallic strip of unit width and length L, consisting of two connected metal layers 1 and 2 (Fig. 2) with different values of their thermomechanical parameters (coefficients of linear thermal expansion (1)  and (2)  and modulus of elasticity (1) E and (2) E ), used in various electrical appliances. In the initial state at 0 T  bimetallic plate is not deformed and longitudinal strains (1) x  and (2) x  in its layers are equal to zero (Fig.…”