Physical-mechanical properties of composite material based on polyester fibres and mineral binder

Abstract

Most metal railway bridges have reinforced concrete slabs as the substructure for the ballastless bridge deck. The slabs are laid on the longitudinal metal beams of the span structures with a rubber-wood interlayer in-between so that to level the base and evenly distribute the load. It is easy to lay, and its physical and mechanical characteristics ensure even load distribution and minimize stresses in the slabs. However, due to the biodegradation of wood, such an interlayer is of low durability. Ukrainian State University of Railway Transport has developed a rolled composite material made of bulk non-woven material made of anisometrically oriented polyester fibres and sand-cement mineral mixture for the interlayer, which is being laid by implementing a technological solution. As shown, it is advisable for the composite material to provide the deformation modulus E close to the integral deformation modulus of the rubber-wood interlayer, which is yet to be explored. The experimental studies of the strength f and the integral deformation modulus E of the rubber-wood interlayer were performed. It was found that for pine wood, f and E are 58 and 5.5 MPa, and for oak these values are144 and 7.9 MPa, respectively. The physical and mechanical properties of the composite interlayer were also investigated. The compressive deformation diagrams were obtained for the composite material with  = f() and  = f() at different types of cement (Portland cement and calcium-aluminate cement), the thickness of non-woven material 10 and 20 mm, S:C ratios from 0 to 2, the consumption of mineral mixture (M) per 1m3 of non-woven material (NM) (M:NM) from 167 to 1,000 kg/m3 . It was found that the values f and E increase if the thickness of non-woven material and the S:C ratio decrease, while the consumption of the mineral mixture per 1 m3 of non-woven material increases. The diagrams of dependency of f and E on the S:C ratio and M:NM were constructed. The regression equations were obtained and their solution was used to develop compositions of composite mineral that provide E = 144 MPa, for example, a composition based on Portland cement, non-woven material with a thickness of 10 mm, S:C = 0.11, and M:NM = 1,000 kg/m3 . Some compositions of the composite material for the interlayer are recommended.