Innovative Lightweight Concrete (LWC) for Precast Structures

This paper reports a study based upon experimental investigation, which evaluates the flexural behavior of lightweight concrete (LWC) beams reinforced with glass fiber-reinforced polymer (GFRP) bars. Three reinforced concrete (RC) beam specimens (200 mm wide x 300 mm high x 3,100 long) were fabricated and tested under four-point bending up to failure. Two specimens were made with LWC while one specimen was made with normal weight concrete (NWC) as a reference specimen. The test variables were concrete density (LWC and NWC) and longitudinal GFRP reinforcement ratio. The beam test results are introduced and discussed in terms of cracking behavior, deflection, and failure modes. The experimental results show that the LWC and NWC beam specimens failed as a result of concrete crushing. The normalized moment capacity of the GFRP-reinforced LWC beam specimens was not significantly influenced compared to the GFRP-reinforced NWC counterpart.

I. Introduction

Lightweight concrete (LWC) allows for the production of reinforced concrete (RC) members that have a reduced own weight while maintaining a concrete strength that is of the same magnitude as normal weight concrete (NWC) [1]. Pantelides et al. [2] said “Reducing the own weight of a RC structure could considerably decrease the section dimensions of beams, slabs, columns, and foundations, which would enhance cost savings. An additional benefit of RC elements made with LWC is cutting lifting and transportation costs in the case of precast elements. LWC has been used for different purposes in the building industry”. For precast structures, Fig. 1 shows the construction of East Surrey Newspaper, Limited at Redhill. The structural frames with cladding panels were cast with LWC, using Solite aggregate. The concrete strength was 50 MPa with a density of 1900 kg/m3. Fig. 1.

Office block (construction) for east surrey newspaper, ltd., redhill [3].