Behaviour of precast concrete panels with environmentally-friendly hollow composite reinforcements

Behaviour of precast concrete panels with environmentally-friendly hollow composite reinforcements

The construction industry is one of the main emitters of pollutants and is worsening the condition of the environment. In order to cope with this alarming situation, construction engineers and companies are trying to advance their existing materials and construction systems, paving the way for new and environmentally friendly technologies. Recently, hollow concrete panels (HCPs) reinforced with steel bars have been employed extensively for slab, decks, and wall panels because they offer higher structural efficiency compared to solid concrete panels with the same concrete section. Several experimental studies have been conducted to investigate the behaviour of HCPs under different loading conditions and have found that their structural performance is critically affected by the presence of the hollow core. The section is therefore weaker, which can result in premature failure in flexure, shear and compression. Therefore, this research systematically investigated the behaviour of HCPs reinforced with a hollow composite reinforcing system (CRS) and steel bars to develop a new, durable, lightweight, highly sustainable, and environmentally-friendly construction system.

The first investigation focused on the flexural behaviour of precast concrete panels reinforced with steel bars and with different number of CRSs. Four-point bending tests were conducted on six precast concrete panels. The results showed that the CRS could minimise crack propagation of concrete, make the crack path longer by changing the crack directions, and delay the start of yielding of bottom steel resulting in enhanced load carrying capacity by 112% and the initial stiffness by 24%. The increase in the number of CRSs increased the load carrying capacity and helped maintain the initial panel’s stiffness even after yielding of the bottom steel. The effect of epoxy applied on the CRS surface increased the stress distribution and reduced the crack propagation due to enhanced composite action between the concrete and CRS. The finite element (FE) modelling was carried out, which confirmed the failure of the panels occurred due to the concrete crushing and not due to the failure of CSR.

The effect of CRS spacing and span–to-depth (