The study on the influence of concrete and reinforcement content on the crack resistance of three-layer panel slab

Abstract

Three-layer reinforced concrete panel slabs with a middle layer made of low thermal conductivity materials and outer layers made of load-bearing concrete materials are gradually becoming a promising structure for use as enclosure systems in construction projects. The behavior of the three-layer reinforced concrete structure using different types of concrete under the influence of loads is significantly affected by the interaction between the different material layers and the reinforcement used. In this paper, the authors investigate the effect of the elastic modulus ratio between the two different types of concrete in the inner and outer layers, as well as the steel reinforcement content, on the cracking resistance of the three-layer reinforced concrete panel slab under load. The research method involves converting the cross-sectional area of the multilayer material structure into a homogeneous material based on the elastic modulus ratio between the material layers and applying the methods and formulas outlined in the Vietnamese Standard 5574-2018. The research results show that: the elastic modulus ratio of the concrete in the inner and outer layers, and the steel reinforcement content used in the three-layer panel slab, significantly affect the cracking resistance and deflection of the structure under load. As the elastic modulus ratio between the inner and outer concrete layers increases, the cracking resistance of the slab improves, and the deflection of the multilayer slab
decreases. In the three-layer panel slab investigated, the change in the elastic modulus ratio between the lightweight concrete in the inner layer and the loadbearing concrete in the outer layer has a greater impact on the cracking resistance of the slab than the change in the steel reinforcement content. The research results help designers of three-layer panel slabs select appropriate parameters that meet the cracking resistance requirements for the slab.

Keywords: Multi-layer reinforced concrete structures; lightweight concrete; low thermal conductivity concrete polystyrene concrete.