Mix design, formwork pressure and bond characteristics of special self-consolidating concrete

Investigations were conducted to develop a special type of self-consolidating concrete (SCC) with two types of lightweight aggregates. Fresh and hardened properties, formwork pressure development and bond strength behaviour of lightweight SCC (LWSCC) mixture were studied compared with normal weight SCC (NWSCC). Five LWSCCs with expanded shale and slag aggregates having satisfactory fresh and hardened properties were developed in addition to a NWSCC. Using these SCCs, concrete block and column specimens were cast and tested by direct pullout of embedded reinforcing bars to study the influences of various factors affecting bond stress such as concrete strength, curing age, rebar types, concrete types, concrete cover, and embedded length in conjunction with testing for formwork pressure development.;The minimum 28-day compressive strength of LWSCCs was 34 MPa. Formwork pressure in LWSCC was reduced by up to 50% compared to NWSCC. The pullout results showed that the bond performance of LWSCC was the same or even better than NWSCC. Top-bar factor confirmed the excellent bond performance of LWSCCs and the uniformity of bond stress along the height of column specimens. Based on the experimental results, new bond models for LWSCCs were proposed to predict the maximum bond stress.