Abstract
A broad experimental study has been performed to characterize the early hydration and setting of cement pastes prepared with Class H oil well cement at water-to-cement ratios (w/c) from 0.25 to 0.40, cured at temperatures from 10 to 60 °C, and mixed with chemical additives. Chemical shrinkage during hydration was measured by a newly developed system, degree of hydration was determined by thermogravimetric analysis, and setting time was tested by Vicat and ultrasonic velocity measurements. A Boundary Nucleation and Growth model provides a good fit to the chemical shrinkage data. Temperature increase and accelerator additions expedite the rate of cement hydration by causing more rapid nucleation of hydration products, leading to earlier setting; conversely, retarder and viscosity modifying agents delay cement nucleation, causing later setting times. Lower w/c paste needs less hydration product to form a percolating solid network (i.e., to reach the initial setting point). However, for the systems evaluated, at a given w/c, the degree of hydration at setting is a constant, regardless of the effects of ambient temperature or the presence of additives.
Original language | English (US) |
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Pages (from-to) | 1023-1033 |
Number of pages | 11 |
Journal | Cement and Concrete Research |
Volume | 40 |
Issue number | 7 |
DOIs | |
State | Published - Jul 2010 |
All Science Journal Classification (ASJC) codes
- Building and Construction
- General Materials Science
Keywords
- A. Hydration
- A. Kinetics
- A. Workability
- C. Shrinkage
- D. Admixture