A NEW CONCRETE INCORPORATING WASTEPAPER SLUDGE ASH (WSA)

This paper reports the results of a preliminary study into the properties of concrete manufactured with various binder blends incorporating Portland cement (PC), Wastepaper Sludge Ash (WSA) and Ground Granulated Blast-furnace Slag (GGBS). The PC was partially replaced with either WSA or a 50:50 blend of WSA:GGBS at replacement levels of 0%, 20%, 40%, 60%, 66% and 80%. Compressive strength data were obtained for concrete manufactured from the various blends after water curing for 7, 28 and 90 days. The compressive strength data are complemented with workability and initial and final set data. At the very high replacement levels (i.e. 80% replacement of PC) the concrete did not remain intact when introduced to the curing water after demoulding. This is attributed to the effect of the water reducing-retarding admixture, which is necessary to offset the high water demand of WSA, increasing significantly the setting times (especially the final set) of the systems investigated. The strength of both the PC-WSA and the PC-WSA-GGBS systems do indicate however that even at high replacement levels (up to 60%), compressive strength is not compromised and in some cases exceeds that of concrete manufactured with a 100% PC binder.

• INTRODUCTION

• MATERIALS

• EXPERIMENTAL

• RESULTS AND DISCUSSION

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES