Design and Characterization of Low-heat and Low-alkalinity Cements

Investigations were conducted to formulate and characterize low-alkalinity and low-heat cements that would be compatible with an underground waste repository environment. Several systems comprising Portland cement, a pozzolan (silica fume or fly ash) and blastfurnace slag were compared. All blends were characterized by high amounts of additions, the Portland cement (PC) fraction ranging from 20-60%. Cement hydration was studied using several techniques: X-ray Diffraction, TGA-DTA, calorimetry, pore solution extraction and microscopy. The most important result obtained with some ternary blends was the drop in the pore solution pH by more than 1 unit as compared with control samples elaborated with commercial cements. The alkali content (~1 to 4 mmol/L) of the interstitial solution was also strongly reduced. The blends exhibited a low-heat output as required. Leaching tests carried out in pure water indicated a very slow decalcification of the samples. Several techniques such as optical microscopy, SEM/BSE, X-ray microanalysis, or X-ray diffraction were compared to estimate the degraded thickness.

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  • English

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  • Accession Number: 01099370
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 5 2008 12:13PM