Bond strength of rebars in cement stabilised rammed earth: Fid-Bau Portal

Bond strength of rebars in cement stabilised rammed earth

Lepakshi, R. / Venkatarama Reddy, B.V.

Highlights • Flexural strength of unreinforced rammed earth (URE) is low. Reinforcing RE structural components improves the same. • Present study examined the bond between rebar and cement stabilised rammed earth (CSRE). • Pullout bond strength and bond force-slip relationships were established. • Dry density of RE, rebar diameter and type of reinforcement greatly influence the pullout bond strength of rebars in CSRE. • Ribbed rebars develop good bond strength with the CSRE matrix.

Abstract Rammed earth construction involves compacting processed soil in progressive layers inside a rigid formwork. Rammed earth structural elements experience bending stresses under lateral loads such as wind and earthquake loads. The flexural strength of cement stabilised rammed earth (CSRE) walls is low. Reinforcing the rammed earth will improve the flexural strength of rammed earth to resist lateral loads. There is hardly any information on the bond strength of rebars embedded in CSRE matrix. There is a need to examine the bond developed between rebar and CSRE matrix. This paper focuses on determining the bond strength between rebar and CSRE; establish bond force – slip relationships for reinforced CSRE. The variables considered in the study included two dry densities (1800 and 1900 kg/m³), two cement contents (7% and 10%) and three types of rebars. The CSRE cubes embedded with different types of rebars were tested for pullout loading under two testing conditions (dry and wet). The bond strength of rebars in CSRE matrix was found to be greatly influenced by the dry density of the CSRE and the type of reinforcement. The bond strength of deformed rebars is higher than the plain rebars irrespective of the specimen density.