Hydration characteristics of waste sludge ash that is reused in eco-cement clinkers

Abstract The study reports on the hydration characteristics of eco-cement clinkers produced with waste sludge ash as raw components. The tested mixtures were composed of different types of waste sludge ash, including sewage sludge ash, water purification sludge ash, limestone, and ferrate, prepared using the optimum proportioning method. The mixtures were burned at 1400 °C for 6 h. The clinkers thus obtained were quantified and the hydration characteristics of the eco-cement pastes prepared from the waste sludge ashes. The setting time, compressive strength, hydrates and porosity distribution were examined at various ages. The 28-day compressive strength of the early high strength developing of eco-cement C paste outperformed that of ordinary Portland cement paste by 3 MPa. It is supposed that the large quantity of limestone used provided CaO, which in turn enhanced the formation of C 3 S, leading to the greater compressive strength development in the eco-cement C paste. From the porosity distribution, shown by the Mercury Intrusion Porosimetry results, it was found that, with increasing curing ages, the gel pores ( 0.01 μm) decreased—a result that shows that hydrates had filled the pores. This resulting densification and enhanced later strength were caused by the shifting of the pore size distribution to a smaller diameter range.

[1]  Fabio Carassiti,et al.  Evaluation of chloride content in concrete by X-ray fluorescence , 1997 .

[2]  P. K. Mehta.  PROPERTIES OF BLENDED CEMENTS MADE FROM RICE HUSK ASH , 1977 .

[3]  Jean-Emmanuel Aubert,et al.  USE OF MUNICIPAL SOLID WASTE INCINERATION FLY ASH IN CONCRETE , 2004 .

[4]  D. Roy,et al.  The potential of fly ash for cement manufacture , 1993 .

[5]  D. Pirtz,et al.  Use of Rice Hull Ash to Reduce Temperature in High-Strength Mass Concrete , 1978 .

[6]  Pen-Chi Chiang,et al.  Utilization of sludge as brick materials , 2003 .

[7]  J. Tay,et al.  Sludge Ash as Filler for Portland Cement Concrete , 1987 .

[8]  Kuan-Yeow Show,et al.  Clay‐Blended Sludge as Lightweight Aggregate Concrete Material , 1991 .

[9]  James E. Alleman,et al.  Constructive sludge management: biobrick , 1984 .

[10]  J. Tay,et al.  SLUDGE ASH AS LIGHTWEIGHT CONCRETE MATERIAL , 1989 .

[11]  Jorge Alberto Soares Tenório,et al.  Laboratory testing of the use of phosphate-coating sludge in cement clinker , 2000 .

[12]  Jordi Payá,et al.  Use of sewage sludge ash(SSA)-cement admixtures in mortars , 1996 .

[13]  J. Chudoba,et al.  Determination of Kinetic Constants of Activated Sludge Microorganisms , 1985 .

[14]  J. Tay,et al.  Bricks Manufactured from Sludge , 1987 .

[15]  K. J. Reid,et al.  COMPRESSIVE STRENGTH OF MUNICIPAL SLUDGE ASH MORTARS , 1989 .

[16]  J. Tay,et al.  Resource recovery of sludge as a building and construction material – a future trend in sludge management , 1997 .

[17]  A. Idris,et al.  Characteristics of slag produced from incinerated hospital waste. , 2002, Journal of hazardous materials.