LOW HEAT SULFATE RESISTANT CEMENT-ITS STRENGTH AND DURABILITY IN CHEMICALLY AGGRESSIVE ENVIRONMENT

The paper deals with the development of low heat sulfate resistant (LHSR) cement produced by activation of granulated slag obtained from blast furnace, copper and phosphate industries with calcium sulfate hemihydrate. A rapid setting cement of high strength was obtained. The setting time of cement was prolonged with a small addition of set retarder without adverse affect on strength. Better strength results with low heat of hydration than the anhydrite activated cement were achieved. Data confirmed that granulated blast furnace slag can be replaced with copper or phosphatic slag upto 10 percent by mass without appreciable fall in strength. The LHSR cement on hydration produce ettringite, C-SH and C₄AH₁₃ as the major hydraulic products. The durability of LHSR cement vis-a-vis ordinary Portland cement (OPC) was examined for its use in sulfate solutions such as Na₂SO₄.10 H₂O, (NH₄)₂SO₄, MgSO₄ and in a mixture of NaCl and Na₂SO₄.10 H₂O. Data upto 180 days of curing in sulfate solution is reported. A fall in compressive strength of LHSR cement as well as OPC was recorded. However, fall of strength was lower in LHSR cement than the OPC. The gain in higher strength in LHSR cement in sulfate solutions may be assigned to the formation of enhanced quantity of C-S-H and decrease in Ca(OH)₂ and ettringite. The LHSR cement may be used in construction work prone to sulfate attack.

• INTRODUCTION

• EXPERIMENTAL DETAILS

• RESULTS AND DISCUSSION

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES