Heat-resistant concretes containing waste carbon fibers from the sailing industry and recycled ceramic aggregates

Abstract

The article describes a new model of the production of heat-resistant concrete in which waste recycled materials were used. The aim of the work was to compose a composite that would have high strength parameters despite being loaded with rapidly rising temperatures. The simulation of such conditions was aimed at analyzing the possibility of using this composite in tunnel construction.Aluminous cement was used as the binder for the concrete. The aggregate used was ceramic waste from industrial sanitary ceramic waste. Carbon fibers from the production of carbon fiber sailing equipment were used as an additive to modify the properties of the concrete. The comparative modifier of the composite was polypropylene fibers normally used in this type of applications. All concretes were tested for basic properties such as consistency, bulk density, water absorption, compressive and tensile strength without and after annealing. The test samples were also subjected to microscopic examination.All the composites studied were characterized by similar values of consistency, density and absorbability. In the aspect of testing the composites not annealed in the case of analysis of tensile strength, the addition of all types of fibers was positive. In the case of testing of non-annealed composites in the aspect of compressive strength, the effect of the addition on this feature was small. The differences in the tested strengths were up to 2%. The mentioned parameters tested after annealing indicated a significant role played by the additives. The most favorable parameters were evaluated for composites with waste carbon fibers. The value of tensile strength of samples with carbon fiber additives after annealing was 3.1 times higher than that of samples with comparative polypropylene fibers. The investigated compressive strength value for the composite with the recycled additive was 30% higher than that for the composites with the traditional additive. Microscopic analyses explained the reasons of the changes occurring in the composites.The research allowed to recommend the use of waste carbon fibers in the production of refractory composites resistant to thermal shocks. The properties evaluated in the research work also allowed to propose the use of this type of composites in concrete tunnel construction.