Long-term stability and tensile behaviour of chemically-prestressed high-strength concrete plates reinforced with carbon textile reinforcement

Carbon textile reinforcement is a relatively new form of Carbon Fiber Reinforced Polymer (CFRP) reinforcement, which in addition to its non-corrodible behaviour, has increased flexibility. Combining such reinforcement with high-strength concrete allows for producing ultra-thin concrete plates with numerous applications. However, the nature of the high-strength concrete used and the material-minimized design result in shrinkage and serviceability-related issues. To address this, the feasibility of utilising the chemical prestressing technology to enhance the structural performance of textile-reinforced concrete was investigated herein. Calcium sulfoaluminate (CSA) was used as an expansive additive. Based on this, twenty-four concrete plates of dimensions 500 mm × 150 mm × 30 mm were cast. To study the influence of different expansion rates on the resulting stresses, the plates were divided into four groups based on the CSA replacement ratio namely: 0 % CSA, 12.5 % CSA, 15 % CSA, and 17.5 % CSA. The long-term stability of the resulting stresses was monitored for six months using the distributed fibre optic sensor (DFOS) technology. Additionally, regular tests were also performed during the six-month period to determine the influence of the CSA on the mechanical properties of concrete. In the end, all the concrete plates were tested under a direct tension test to verify the existence of the prestressing stresses. The results have revealed that the proposed concrete mixture can yield significant expansions which has led to the development of significant tensile stresses inside the textile reinforcement reaching a final average stress of 902 MPa for 17.5 % CSA replacement ratio. This has led to the development of compressive stresses inside the concrete, which were verified by the direct tension test. Additionally, the cracking behaviour was significantly enhanced by the prestressing action. Nevertheless, high CSA replacement ratios such as 17.5 % can lead to some damage to the concrete strength. • The feasibility of utilising the chemical prestressing technology in carbon textile reinforced concrete was investigated. • Distributed fibre optic sensor technology was used to monitor the stability of the developed stresses for six months. • The proposed expansive concrete mixture led to the development of stable and considerable stresses inside the reinforcement. • The chemical prestressing technology improved the structural behaviour of textile-reinforced concrete considerably.