The characteristic of very high-performance concrete (VHPC)

Abstract

A Very High-Performance Concrete (VHPC) has compressive strength in the range 120-150 MPa and high flowability. However, there is no VHPC mix as a repairing grout in Indonesia. This study presents the mix design of VHPC using Indonesian by-product materials to achieve compressive strength of 120 MPa. A sequence experimental method determined the suitable material to replace fine sand, ground quartz and superplasticizer. Then, the optimum mix design was tested with compressive strength, splitting tensile strength, slump flow, permeability, and shrinkage tests. In addition, the effect of 35 mm length hook-end steel fiber in the VHPC by 2% of volume was observed. The optimum mix design used cement, silica fume, and glass powder as binder with the ratio of 3:1:1. The ratio of sand and binder was 0.88. The water to binder ratio (w/c) was 0.11 using superplasticizer and accelerator which was kept on 4.3% of cement weight each. This mix design achieved a compressive strength of 128 MPa at 28th day. VHPC had high shrinkage whether volumetric or longitudinal. However, the steel fiber was able to restrain the shrinkage and increased the tensile strength. Nevertheless, the hook-end steel fiber is not recommended because its large size decreased the compaction and eventually decreased the compressive strength.