A discussion of the paper: “Lithium salts as set accelerators for high alumina cements” by T. Matusinović and D. Čurlin
✍ Scribed by John Bensted
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 124 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0008-8846
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✦ Synopsis
Drs Matusinovi~ and Curlin have undertaken a very useful investigation of the acceleration of setting in calcium aluminate cement CAC (high alumina cement HAC) by lithium salts (1). They have investigated the reasons why U + ions have a much greater influence in accelerating the setting time than the other alkali metal cations and why OH" ions have more influence on the acceleration of setting than the other anions investigated, viz. chloride CI', formate CHO2", fluoride F', acetate C2H302" and phosphate PO43-, at 0.01% mass fractions. As well as giving rapid setting, lithium salts normally permit higher early strength development with CAC. Kinetic investigations have shown that the accelerated setting process follows a simple first order reaction rate for the first 6 hours of hydration at water/cement 0.24. From this work it has been concluded that the accelerative action of lithium salts is based upon a shortening of the induction period, whilst they have no effect per se on the actual rate of hardening.