Preparation and Performance of Ultra-high Strength Concrete with Good Toughness

A new type of ultra-high strength concrete(UHSC) with compressive strength of 220 MPa and flexural strength of 70 MPa was prepared by utilizing composite mineral admixtures,natural fine aggregates,and short and fine steel fibers in the normal shaping and curing condition.The dynamic mechanical behavior of UHSC with different mineral composition were investigated.Meanwhile the pore-structure,interfacial zone and hydration products were investigated by mercury intrusion porosimetry(MIP),scanning electron microscope(SEM),energy dispersion X-ray analysis(EDAX) and X-ray diffraction(XRD).The experimental results show that mineral admixtures can effectively optimize the micro-structure of ITZ and improve the formation of C-S-H gel,and consequently improve the impact and abrasion resistance.