Title:
Effect of Phosphate-Based Compound on the Hydration of Cement and Cement components
Author(s):
V. S. Ramachandran and M. S. Lowry
Publication:
Symposium Paper
Volume:
148
Issue:
Appears on pages(s):
131-152
Keywords:
admixtures; calcium aluminates; calcium silicates; calorimeters; cements; gypsum; hydration; portland cements; Materials Research
DOI:
10.14359/4105
Date:
9/1/1994
Abstract:
The influence of a phosphonate-based admixture called aminotri (methylene phosphonic acid) (ATMP) on the hydration of C 3A, C 3A and 25 percent gypsum, and C 3S and Type I cements (normal, high-alkali, and low-alkali) was evaluated. Isothermal conduction calorimetric investigations of various mixes containing 0.03 to 0.05 percent of phosphonic acid, at water-cement ratios of 0.35 and 1.0, were carried out up to 72 hr. The ATMP acted as a super-retarder for all mixes studied. At a dosage of only 0.05, the exothermal effect for one of the high-alkali Type I cements was delayed by about 16 hr. The hydration of C 3A and C 3S was also retarded by about 40 to 45 min and more than 50 hr, respectively, at a dosage of 0.05 percent. In the C 3A and gypsum system, the third peak corresponding to the reaction of C 3A with ettringite was extended by about 8 to 9 hr.