Title: Deicer Salt Scaling Resistance of High Strength Concretes Made With Different Cements

Author(s): R. Gagne, M. Pigeon and P. C. Aitcin

Publication: Symposium Paper

Volume: 126

Issue:

Appears on pages(s): 185-200

Keywords: aggregates; air entrained concretes; air-entrainment; cement types; compressive strength; curing; deicing; durability; freeze thaw durability; scaling; silica; Materials Research

DOI: 10.14359/2115

Date: 8/1/1991

Abstract:
Seventeen concrete mixtures were prepared to evaluate the deicer salt scaling resistance of some high-strength concretes with a 28-day strength in the 60 to 90 MPa range. A 0.30 water/(cement + silica fume) ratio was used for most of the mixtures and 3 additional mixtures were prepared with a 0.26 water/(cement + silica fume) ratio. In the 0.30 mixtures, two types of cements and a silica fume were used (Type III, Type III + percent silica fume, Type 1 + 6 percent fume), and in the 0.26 mixes, only Type 1 + 6 percent silica fume. Most of the concrete specimens were prepared with different air contents to produce a relatively low spacing factor and a high spacing factor. A very dense dolomitic limestone and a granitic gravel were used as a coarse aggregates. The curing period varied between 1 and 28 days. All the specimen were submitted to 150 daily cycles freezing and thawing in accordance with ASTM C 672, using sodium chloride as a deicer. Weight loss was measured to evaluate the deterioration of the concrete surfaces. The scaling resistance of the specimens made with a Type III cement (with the limestone aggregate or the granitic aggregate) was found to be very good in all cases, irrespective of the length of curing, the silica fume content or the spacing factor values. The non-air-entrained concretes made with a Type I portland cement also had a good scaling resistance after 24 hr of curing but, in this case, a better durability was obtained by using a longer curing period (7 to 28 days). For all concretes, the weight loss after 50 cycles was lower than 0.75 kg/mý and under 2 kg/mý after 150 cycles, and no clear relationship was found between the scaling resistance and the spacing factor. However, there are indications that when a high strength concrete can perform very well in a scaling test without air entrainment, the use of a relatively high air content can somewhat reduce its scaling resistance. Based on these results and others from recent publications, it seems that the use of a water/(cement + silica fume) ratio of 0.30, a good quality coarse aggregate and a portland cement with silica fume generally allows the production of non-air-entrained concretes with a good deicer salt-scaling resistance, even after only 24 hr of curing. It is also possible, with certain Type III cements, to produce deicer salt scaling resistant non-air-entrained concretes without using silica fume.