The effect of glass powder on the microstructure of ultra high performance concrete

Glass powder prepared of various types of recycled bottles was used in ultra-high performance concrete (UHPC). Experimental investigation of glass powder as complete replacement for quartz powder and silica fume showed that UHPC with improved micro-structural and compressive strength properties can be prepared. Glass powder milled to micro-scale undergoes low pozzolanic reaction and acts as catalyst accelerating the dissolution of clinker phases and forms low basicity calcium silicate hydrate (C-S-H). These reactions give positive effect on mechanical and microstructural properties of UHPC. Microstructural investigation was made by mercury intrusion porosimetry (MIP), X-ray diffraction (XRD) analysis and by 29Si MAS NMR analysis. Experimental results revealed that additional compressive strength of 40 MPa can be gained with combination of glass powder and silica fume.