Thin concrete-timber-composite floors reinforced with basalt textile

Abstract

Adding a reinforced concrete layer on top of timber floors, such as dowel beam ceilings (DBC), is a well-established method in retrofitting old buildings. However, the concrete layer thickness of 5-7cm, which is driven by durability rather than strength requirements, comes with additional weight that typically implies supporting and strengthening measures of the existing structure. In this work, we investigate thin basalt textile-reinforced concrete (TRC) layers on top of a DBC to reduce the concrete mass and overall system height. This includes experimental investigations on two large scale timber concrete composite floors with 4.7 m length: (a) ordinary DBC-Steel reinforced concrete (RC) composite floor with a standard thickness of the concrete layer (7cm) and (b) DBC-TRC composite floor with a slender basalt textile reinforced concrete layer (3cm). Test results indicate that the slender DBC-TRC floor exhibits larger deflections by 60 % while having 80 % of the load bearing capacity of conventional DBC-RC floors. Still, in both cases, the serviceability and ultimate limit state requirements are fulfilled, making the TRC system a viable solution for real applications with its substantially lower weight.