A lightweight concrete solution for a timber concrete composite floor system

Diagram of a timber concrete composite floor system


The hybrid cross-laminated timber (CLT) with concrete floor system (TCC) has drawn attention as an attractive application for mid-rise and commercial buildings. Interest in this type of structure is primarily motivated by the optimal structural performance and construction cost. In comparison to conventional flooring systems, TCC have lower self-weight and maintain a reasonable bearing capacity. However, the drawback of using conventional concrete in this composite system is its heavy self-weight, resulting in increased dead load of the building as well as weaken the benefit of using timber as lightweight and cost-effective structural material. Hence, in this study, a structural strength lightweight concrete can be developed in order to reduce the self-weight with minimum reduction on the mechanical performance of TCC structure. Moreover, due to the limited studies on such composite structure, the structural performance and design criteria of timber-lightweight concrete composite system (TLCC) is still less known. This research focus on evaluating the effect of lightweight concrete on the structural performance of TCC floor systems.

Key outcomes

A practical mixture of lightweight concrete that maintains the similar compressive strength of normal concrete (≥32MPa) with up to 35% weight reduction has been developed as the first stage study. The effects from different parameters on the mechanical properties of lightweight concrete have been examined including cement content, replacement of industrial waste material and types of lightweight aggregates. As the second part of this study, the composite specimens consisting of CLT, selected lightweight concretes (density between 1500-1800 kg/m3) and different connection systems have been manufactured for shear test. The effects from concrete densities and types of connection systems on the ultimate shear capacity and the failure modes of TLCC have been studied and will be used for validation of numerical analysis.

Research team

  • Tian Tang
  • Prof Tuan Ngo
  • Dr Ali Kashani
  • Dr Xuemei Liu

Research partners and collaborators

  • XLam