A Study of Waterproof Reinforcement Layers for the Post-Cracking Behavior of Fiber Reinforced Concrete

Abstract

In this study, in order to protect the concrete layer from slab sinking cracks in the factory floor layer, four types of reinforcing materials with a notable waterproof performance are fixed at the bottom. Furthermore, short fibers mixed with concrete in order to evaluate the load transfer mechanism and residual stress retention ability are used. The change in flexural strength due to the waterproof reinforcement varied from about 10 to 48% depending on the type of reinforcing material, and the flexural strength of the specimen reinforced with Typar and Preprufe was demonstrated to be the best. Additionally, the increase in flexural strength due to the combination of the SF20 + Typar and MF2.8 + Preprufe specimens was remarkable. After the concrete matrix cracking, the toughness resulting from the fiber pull-out resistance and the increase in the reaction force of the waterproof reinforcement showed a marked improvement in all the test specimens. The test specimen reinforced with Typar demonstrated the best crack resistance regardless of the fiber type. The crack transfer mechanism in the concrete floor can be summarized in that the fiber pull-out resistance and the reaction force of the waterproof reinforcement immediately after cracking causes a reduction of the crack length (l) from the rapid load transfer, and as a result, the fiber bridging zone (lf) is widely protected. Therefore, it is determined that the residual stress rises, maintains, and slows, as the resistance of the fiber bridging in the cracked section and the effect of the waterproofing reinforcement layer is combined.