Flexural Strengthening of RC Slabs with Lap-Spliced Carbon Textile Grids and Cementitious Grout

This paper presents a new textile-reinforced concrete (TRC) installation method for strengthening structurally deficient or damaged reinforced concrete (RC) structures with grouting. In this study, cementitious grout was used as a matrix for the TRC system. TRC coupon specimens with different lap-splice lengths were tested under tension to determine the minimum textile lap-splice length. The minimum lap-splice length of the sand-coated textile was evaluated as 150 mm. The performance of the TRC-strengthened RC slabs with the proposed installation method. The lap-spliced textile was experimentally validated by a flexural failure test. Five RC slabs were strengthened by one ply of sand-coated carbon textile grid with and without the lap-splicing and 20 mm-thick cementitious grout and were tested in flexure. Among the TRC-strengthened RC slab specimens, two specimens were re-strengthened RC slabs with the TRC system. The TRC strengthened slab, for which the lap-splice length of the textile was 50% smaller than the minimum lap-splice length, failed at the load level of steel yield. On the other hand, the ultimate load-carrying capacity of the RC slabs strengthened by the TRC system with textile lap-splicing decreased by at least 6% relative to that without textile lap-splicing. Furthermore, the results of a flexural test for the TRC re-strengthened slabs indicate that the ultimate load-carrying capacity of the TRC re-strengthened slabs is almost the same as that of an undamaged slab strengthened with the TRC system.