Confinement of concrete columns using CFRP and expanded grout

ABSTRACT The occurrence of past serious earthquakes led to the demolition of most of already built reinforced concrete (RC) structures due to improper seismic design. Further studies showed that reduced ductility and low shear strength were the main reasons for the failure of structural members (such as columns). Hence, considering the incorporation of shear strength and ductility in structural design became vital to enhance resistance to environmental loads (such as earthquake). Low-strength concrete is generally in practice in the progressing countries like Pakistan. Different approaches and methods have been used to retrofit and repair the ageing structures using different techniques. The present study focuses on the experimental investigation of confining of concrete columns by pre-tensioning carbon fibre-reinforced polymer (CFRP) with expanding grout. A number of concrete cylinder specimens were prepared using selected quantities of expanding grout, which produced various initial pressures. The behaviour of pre-tensioned confined concrete with non-pre-tensioned confined and unconfined concrete was compared. It was also indicated that using CFRP along with expanding grout can enhance the engineering properties (axial stress and elastic modulus) of columns. It was comprehended that an increment in the initial confining pressure resulted in increment in axial stress as well as axial and lateral strains.