Effectiveness of sealers in counteracting alkali-silica reaction in plain and air-entrained laboratory concretes exposed to wetting and drying, freezing and thawing, and salt water

Abstract

Low- and high-alkali, plain and air-entrained large concrete cylinders, 255 mm in diameter by 310 mm in length, were made with a highly alkali–silica reactive limestone. After curing, a number of cylinders were sealed with silane, oligosiloxane, polysiloxane, linseed oil, or epoxy, with others subjected to 179 freezing and thawing cycles in humid air (one cycle per day). All cylinders were then subjected to 14-day exposure cycles, including in the most severe case periods of humid storage in air, drying, wetting in salt water, and freezing and thawing cycles. All low-alkali specimens did not either expand or develop surface cracking, even those with a deficient air void system and exposed to freezing and thawing cycles. All unsealed high-alkali cylinders subjected early to a series of freezing and thawing cycles did not significantly expand during these cycles, but presented high expansion afterwards. Wetting and drying significantly reduced alkali–silica reaction (ASR) expansion compared with constant humid storage; however, it promoted map-cracking. Regardless of the air content, freezing and thawing increased greatly the concrete expansion in the presence of ASR, even after ASR was almost complete; freezing and thawing also greatly promoted surface cracking. On the other hand, all cylinders early sealed with silane, oligosilixane, or polysiloxane did not either significantly expand or show map-cracking, whatever the exposure conditions and the air content; these cylinders progressively lost mass with time. On the other hand, the epoxy resin was not effective. The linseed oil prevented map-cracking while significantly reducing expansion, however not sufficiently. After one or 1.5 years, some expanding cylinders were sealed with silane, oligosiloxane, or polysiloxane; they started to loose mass and contracted immediately after being sealed, whatever the exposure conditions. The results obtained thus indicate that a good sealer may greatly improve the aesthetic appearance (e.g., map-cracking) and stop expansion of ASR-affected concrete elements of 255 mm or less in thickness, made with a water-to-cement ratio in the range of 0.50, and exposed to wetting and drying, freezing and thawing, and salt water.Key words: air entrained, alkali–silica reaction, concrete, cracking, expansion, freezing and thawing, sealer, silane, siloxane, wetting and drying.

Multi-scale computational modeling for concrete damage by mixed pore pressures – case of coupled alkali–silica reaction and cyclic freeze/thaw

“…As a result, even for the air-entrained concrete, the FTC expansion will still take place. This phenomenon is in harmony with the experiments of Bérubé et al (2002) (Figure 12). With air content of 6.4 per cent and 2.4 per cent, concrete is not likely to expand under FTC.…”

“…for the air-entrained concrete, the FTC expansion will still take place. This phenomenon is in harmony with the 20 experiments of Bérubé et al (2002), see Fig. 10.…”

“…However, after the ASR exposure, air bubbles will lose their functions in preventing the FTC expansion. Although it was difficult to quantify the exact experimental conditions in Bérubé et al ’s work (2002), the experimental phenomena can still prove the findings of this study.…”

The presence of ettringite in concrete affected by alkali‐silica reaction and its potential use as recycled aggregate

“…In most cases, concrete deterioration in service occurs due to more than one mechanism, such as freezing/thawing coupled with ASR 7,8 . The presence of one mode of deterioration might accelerate another.…”

Structural Performance of Nuclear Power Plant Concrete Structures Affected by Alkali-Silica Reaction (ASR) Task 2: Assessing Bond and Anchorage of Reinforcing Bars in ASR-Affected Concrete

“…ASR in concrete structures was first identified by Stanton (1940), and considerable research on this topic has been conducted to date, including investigation of the in-situ mechanical properties of reactive mixtures in service (e.g., Clark, 1989;McLeish, 1990;Deschenes et al, 2009;Smaoui et al, 2006), methods to manage the effects of ASR in existing structures (e.g., Fournier et al,2004;Fournier et al, 2010;Charlwood et al, 2012;Bérubé et al, 2002a;Bérubé et al, 2002b;Drimalas et al, 2012) methods to prevent ASR in new structures (e.g., McCoy and Caldwell, 1951;Jensen et al, 1984;Pleau et al, 1989;Lane and Ozyildirim, 1995;Lane and Ozyildirim, 1999;Mather, 1999;Folliard et al, 2006;Bektas et al, 2006;Carles-Gibergues et al, 2008;Thomas et al, 2008;Thomas et al, 2012c;Thomas et al, 2012d) and methods for simulating the effects of ASR on structural components and structures (e.g., Bažant and Steffens 2000;Ulm et al, 2000;Bangert et al, 2004;Saouma and Perotti, 2006;Pesavento et al, 2012;Saouma, 2014) Of particular importance for the present study are investigations into the structural performance of flexural members, specifically those which studied the bond between ASR-affected concrete and deformed bar reinforcement.…”