Hydration Characteristics of Waste Sludge Ash Utilized as Raw Cement Material

The hydration characteristics and the engineering properties of three types of eco-cement pastes, including their compressive strength, speciation, degree of hydration, and microstructure, were studied. These were compared with those of ASTM type I ordinary Portland cement. Results of this study revealed that it is feasible to use sludge ash and steel-making waste to replace up to 20% of the mineral components of the raw material of cement. All the tested clinkers met the toxicity characteristic leaching procedure requirements. All four major components of Portland cement (C3S, C2S, C3A, and C4AF) were found in the waste-derived clinkers. All three types of eco-cements were confirmed to produce calcium hydroxide and calcium silicate hydrates during the hydration process, which increased densification with the curing age. Thermal analysis indicated that the hydration proceeded up to 90 days, with the amount of Ca (OH0)2 and CSH increasing. The chemical shift of the silicates, the resultant degree of hydration, and the increase in the length of the CSH gels with the curing age, were confirmed by 29-Si NMR techniques. It is concluded that compressive strength and microstructural evaluations confirms the usefulness of eco-cement.

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  • Authors:
    • Lin, Kae-Long
    • Lin, Chung-Yi
  • Publication Date: 2005-10


  • English

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  • Accession Number: 01011012
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Nov 24 2005 1:27AM