Alkali-silica reactivity

D. Sharp, and S. Diamond, SHPP-C-343 Eliminating or Minimising Alkali-Silica Reactivity, National Research Council, Washiagton, D.C., 1993. 

Repair field Mitigation of alkali-silica reactivity Corrosion-canceling technologies Low-maintenance, long-life repair of concrete for corrosion protection of embedded steel... 

A.B. Poole, Alkali silica reactivity mechanisms of gel formation and expansion, in 9th International Conference on Alkali-Aggregate Reaction in Concrete 2, 1992, pp. 782-789. 

While corrosion of steel in concrete is a major cause of deterioration it is not the only one. Out in the real world we must not become blinkered to other problems like alkali-silica reactivity, freeze thaw damage and the structural implications of the damage done and of repairs. In this setting, however, we will concentrate on the corrosion issue although there will be passing references to other problems where relevant. 

Corrosion is not the only deterioration mechanism in reinforced concrete. Alkali-silica reactivity (ASR), sulphate attack, thurmasite attack, delayed ettringite formation, freeze thaw, thermal movement, settlement and other movement can all lead to concrete damage and their assessment must be included in the surveys. 

Stark, D. (1991). Handbook for the Identification of Alkali Silica Reactivity in Highway Structures. SHRP-C-315 Strategic Highway Research Program, National Research Council, Washington, DC. 

Alkali-silica reactivity (ASR) is a condition where certain silicateous aggregates are susceptible to the alkalinity in the concrete and react to form silica gel. Silica gel is used as a desiccant because it absorbs moisture. As it absorbs moisture it swells. ASR is characterized by map cracking , and weeping of the gel as a white efflorescence from the cracks (BRE Digest 330,1999). 

There are two known side effects of ECE. The first is the acceleration of alkali-silica reactivity (ASR) and the other is reduction in bond at the steel concrete interface. 

Is there a risk of causing or accelerating alkali-silica reactivity ... 

Stark, D.C. et al. (1993) Eliminating or minimizing alkali-silica reactivity. SHRP (Strategic Highway Research Program) C 343, National Research Coimcil,... 

Handbook for the Identification of Alkali-Silica Reactivity in Higinvay Structures. Provides guidance for the field identification of alkali-silica reactivity (ASR) in Portland cement concrete structures such as highways and bridges. ASR development is assessed on two bases the occurrence and disposition of cracking and displacement of concrete, and the presence of reaction products from ASR. Colour photographs. 48 pages. SHRP-C-315, 10... 

Alkali-SiUca Reactwiiy An Ovennew of Research. Summarizes current knowledge of how alkali-silica reactivity affects concrete. Targets areas for further research. 105 pages. SHRP-C-342, 15... 

Eliminating or Minimizing Alkati-Silica Reactivity. Describes various studies of alkali-silica reactivity (ASR) as it affects highway structures. Discusses procedures to evaluate material for safe use in concrete, means to mitigate ASR and its adverse effects in existing concrete and various tests to detect ASR. 266 pages. SHRP-C-343, 15... 

ASTM C289. 2007. Standard Test Method for Potential Alkali-Silica Reactivity of Aggregates (Chemical Method). Annual Book of ASTM Standards (04.02) 7 pp. 

British Standards Institution (BSI). BS 812-123 1999. Testing aggregates. Method for determination of alkali-silica reactivity. Concrete prism method. BSI, London, 1999. 

Air void and petrographic core samples Alkali-silica reactivity test... 

In a laboratory test of the alkali silica reactivity an aqueous solution of NaCl with a molar concentration of c = 4.00 mol/f is required. The solution is made in the following way An amount of substance of 4.00 mol NaCl is weighed out and placed in a 1000 m measuring cylinder. Water is added and the solution is adjusted to 1000 mi at 20 °C. The density of the finished solution is g = 1.150 g/cm. Determine a) how many g NaCl shall be weighed out for the solution, b) the NaCl content of the solution in wt-% and c) the molality m of NaCl in the solution ... 

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