Physical and Mechanical Properties of Fiber‐Reinforced Cement Composites with High Polyester Fiber Content

Abstract

On a railway steel bridge, the rail track is installed on reinforced concrete slabs. These slabs are placed on the bridge girders, and between them a bedding layer is arranged for load leveling and distribution. In the Ukrainian railway, this bedding layer is made up of rubber and timber. The physical and mechanical properties of this material help to distribute loads effectively. Yet, the biological resistance of even antiseptic‐treated timber does not guarantee the proper service life of the bedding layer. In an effort to make the bedding layer as long‐lasting as the slabs, the product is recommended to be cast from fiber‐reinforced cement composites. The integral deformation modulus was experimentally determined to be about 144 MPa of the rubber–timber bedding layer. It was postulated that fiber‐reinforced cement composites of ultra‐high fiber content would have a similar modulus of elasticity. It is suggested that these composites could be created by saturating a nonwoven polyester material with a mineral blend of Portland or alumina cement and sand. The theoretical and electron‐microscopic analyses showed that the physical and mechanical characteristics of the composites were determined by contacts between the cement hydration products and the fiber surfaces. The physical and mechanical properties of composites of different mineral mixture content per unit volume of nonwoven material and different cement content in the mixture were experimentally investigated; stress–strain diagrams were established and corresponding deformation moduli for the material were determined. No visible failure of the composites was noted and strength was generally considered as the stress where the deformation kept growing without additional increase in stress. Dependencies of deformation modulus and strength on the mineral mixture content per unit volume of nonwoven material and on the cement content in the mixture were established, approximated, and regression equations were obtained, from which composites with a specified deformation modulus were determined