Title: Blended Antifreezing Admixture with Extreme Freezing-Point

Author(s): Anatoly I. Vovk

Publication: Symposium Paper

Volume: 302

Issue:

Appears on pages(s): 279-288

Keywords: antifreezing admixtures; blended admixtures; extreme freezing-point; superplasticizer

DOI: 10.14359/51688103

Date: 6/1/2015

Abstract:
In many countries there are regions with very cold winter climate. To provide for year-round building and construction works antifreezing admixtures must be used. When suitable technology and high performance antifreezing admixtures have been used, ready mix concrete may be delivered and placed at temperature as low as -25 °C. The transfer from “summer” concrete mix to “winter” one implies the addition of optimal amount of antifreezing admixture. In principal, both separate superplasticizer and antifreezing admixture dosing and usage of blended (combined) admixture is possible. In Russia the usage of blended plasticizing-antifreezing admixtures is predominant historically. The prime blended admixtures on the base of sodium formate didn’t freeze down to -15 oC and allowed secure concrete hardening with dosages about 10% of commercial product. At present day such admixtures are unsuitable neither by the dosage level (danger of ASR) nor by the freezing-point. The method for elaboration of blended antifreezing admixture (BAFA) with extreme freezing-point was developed. These admixtures allow building and construction works at a temperature as low as -25 oC with dosages about 1-1.3% for PCE-based admixtures and 1.8-2.2% for PNS-based admixtures. It is important that these dosages ensure superplasticizing effect. Non-chloride non-plasticizing admixture with freezing-point below -40 oC was developed also. The kinetic of concrete strengthening at various temperature regimes has been thoroughly studied.