FLEXURAL BEHAVIOR OF TEXTILE REINFORCED ONE-WAY SLAB MORTAR

Abstract

ABSTRACT Textile reinforced mortar that has developed in recent years is composed of the continuous textile fabric incorporated into the cementitious matrix. The excellent characteristics of the textile reinforcement such as high tensile strength, high modulus of elasticity and bond nature with the mortar promotes the use of this type of reinforcement instead of the steel reinforcement or with the steel reinforcement in reinforcing the mortar. In this thesis the experimental and analytical investigation is carried out to study the flexural behavior of the textile reinforced and the composite (steel and textile) reinforced one-way slab mortar. Twelve one-way slabs with dimensions of (1500 500 50) mm were casted, cured and tested in flexure. Eight of the tested slabs were reinforced with the textile carbon fabric, one with steel reinforcement, one with chopped carbon fibers and two slabs were reinforced with steel in combination with one and two textile reinforcement layers. The experimental results exhibited that the first crack load for the composite (steel with one and two layers of carbon textile reinforcement) slabs increased by (74.2% and 190%) respectively as compared with the slab II reinforced by only the steel reinforcement. As the load of steel reinforcement yielding increased by (115% and 91.5%) and the ultimate load increased by (66% and 103%) respectively as compared with the steel reinforced mortar one-way slab. Furthermore, the crack width is reduced by (67% and 29.4%) respectively at the cracking and at the final stage of loading. Furthermore, the mode of failure is changed from the brittle to the ductile with the combined textile reinforcement. However, increase the area of the textile reinforcement by increasing the number of layers increases the ultimate load by (32% 60.6%) and increase the mid span deflection at this point by (18.7% 37.9%) while the bond factor is reduced by (9.6% 24.84%) with the increase in number of layers. Moreover, the results showed that the (66.67%) removing of weft yarns represents the optimal percentage of removing since the cracking load and ultimate load were increased by (15.85% and 40.72%) respectively, while the mid span deflection at the ultimate load is reduced by about 6.09% as compared with the reference textile reinforced mortar one-way slab. Furthermore, the cracks number and the crack width have remained the same. The addition of the short carbon fibers by (0.25% and 0.5%) leads to increase the ultimate load by (24.19% 31.56%), bond factor by (24.69% 32.22%) while, the ultimate deflection reduced by (11.96% 16.31%) as compared with the control Textile reinforced mortar slab. The results exhibit the superior flexural behavior of the slab that reinforced by textile carbon layers as compared with the slabs reinforced steel reinforcement or short carbon fibers. On the other hand, the results showed the mutual cooperative contribution between the steel and textile reinforcement in bearing the applied stresses.