High strength self compacting concrete (HSSCC) is one of the most common innovation in the world of construction nowadays because not only of its high compressive strength, but it also can be worked with ease. Over time, the quality of this high strength self compacting concrete keep getting better with many kinds of improvements, including by adding some pozzolanic admixture in concrete mixture including the pozzolanic admixture used in this research which is metakaolin. The purpose of this research focused on studying the effect of metakaolin addition on the parameter of SCC, direct tensile strength, and bond strength of HSSCC.

This research use metakaolin as a substitute to some portion of Portland cement in the concrete mixture to study the effect of the substitution on the workability, direct tensile strength and bond strength of the concrete. The metakaolin compositions used in this research are as follows 12.5% ; 15% ; 17.5% ; 20% ; and 22.5%. The specimens used in this research are beam with dimension of 10x10x50 cm for direct tensile strength test, and cylinder with height of 25cm and diameter of 15cm for bond strength test. This research use experimental method. The workability tests in this research include slump flow test for filling ability, V-funnel test for passing ability, and L-box test for segregation resistance. The direct tensile strength test and bond strength test is conducted by using Universal Testing Machine by holding and pulling the specimens until it reaches the maximum load.

This study shows that metakaolin decreases the workability of the fresh concretes, but value of these concrete tests in this research still meets the standard of self compacting concrete. Both the direct tensile strength and bond strength of 28 days old concrete decreases by the addition of metakaolin with the lowest of both value is 3,04 MPa and 0,87 MPa on concrete with metakaolin composition of 22.5%.

Keywords: bond strength, direct tensile strength, high strength self compacting
concrete, metakaolin, workability.