The effect of ground granulated blast-furnace slag finenness and composition on low water-binder ratio concrete for prestressed precast concrete piles

This paper investigates the effect of binder compositions on the strength of concrete after steam and autoclave curing in concretes mixed with ordinary portland cement (OPC), silica fume (SF), and ground granulated blast-furnace slag (GGBS) of different Blaine fineness types. Additionally, it examines the effect of GGBS composition on the fluidity of concrete by combining two types of GGBS with different Blaine fineness and mixing them with OPC and SF. For the strength evaluation, we investigated the case where GGBS was mixed with a single material with Blaine fineness of 8,000cm 2 /g (BS8) and 10,000cm 2 /g (BS10), and the case where it was mixed with two types of materials with Blaine fineness of 6,000cm 2 /g(BS6) and BS8. The results indicated that a compressive strength exceeding 180 MPa was achieved with a water-binder ratio of 12.5% under autoclave curing using the two types of GGBS. For the fluidity evaluation, it compared conditions with water-binder ratios of 0.15 and 0.125, and GGBS compositions of BS6 and BS8, BS6 and BS10, BS8 and BS10.The results showed that BS8 and BS10 had poorer flow properties compared to other GGBS composition at a certain mixing time, but the flow properties improved when the mixing time was extended.