RILEM Recommendations for the Prevention of Damage by Alkali-Aggregate Reactions in New Concrete Structures

Abstract

Volume 17RILEM, The International Union of Laboratories and Experts in Construction Materials, Systems and Structures, founded in 1947, is a non-governmental scientific association whose goal is to contribute to progress in the construction sciences, techniques and industries, essentially by means of the communication it fosters between research and practice. RILEM's focus is on construction materials and their use in building and civil engineering structures, covering all phases of the building process from manufacture to use and recycling of materials. More information on RILEM and its previous publications can be found on www.RILEM.net.The RILEM State-of-the-Art Reports (STAR) are produced by the Technical Committees. They represent one of the most important outputs that RILEM generates-high level scientific and engineering reports that provide cutting edge knowledge in a given field. The work of the TCs is one of RILEM's key functions.Members of a TC are experts in their field and give their time freely to share their expertise. As a result, the broader scientific community benefits greatly from RILEM's activities.RILEM's stated objective is to disseminate this information as widely as possible to the scientific community. RILEM therefore considers the STAR reports of its TCs as of highest importance, and encourages their publication whenever possible.The information in this and similar reports is mostly pre-normative in the sense that it provides the underlying scientific fundamentals on which standards and codes of practice are based. Without such a solid scientific basis, construction practice will be less than efficient or economical.It is RILEM's hope that this information will be of wide use to the scientific community.

Quantitative assessment of alkali silica reaction potential of quartz-rich aggregates: comparison of chemical test and accelerated mortar bar test improved by SEM-PIA

“…Other disadvantages of the CT were suggested by Wigum et al (1997), who pointed out an original restriction of the test only on aggregates containing amorphous varieties of SiO 2 and an influence of variable aggregate grading and the presence of minor or trace amounts of dust influencing the amount of dissolved silica. Ramos (2013) found CT to be poorly sensitive to slowly reactive granitic aggregates. Rolim et al (2012) suggested increasing the grain size of aggregates used in the CT to 0.3/1.18 mm and to prolonge the test period up to 168 h. quartzite (Q0B, f-j), quartz meta-greywacke (Q7C, k-o), and chert (Q3, p-t) taken from aggregate sections unaffected by ASR (a, f, k, p), and from AMBs after 1 (b, g, l, q), 5 (c, h, m, r), 9 (d, i, n, s), and 14 (e, j, o, t) days of testing Quantitative assessment of alkali silica reaction potential of quartz-rich aggregates: comparison… Although the AMBT gives a clear distinction between reactive and non reactive aggregates, it has been criticised in recent studies (e.g., Shayan and Morris 2001;Lindgård et al 2010;Ramos et al 2011).…”

“…Ramos (2013) found CT to be poorly sensitive to slowly reactive granitic aggregates. Rolim et al (2012) suggested increasing the grain size of aggregates used in the CT to 0.3/1.18 mm and to prolonge the test period up to 168 h. quartzite (Q0B, f-j), quartz meta-greywacke (Q7C, k-o), and chert (Q3, p-t) taken from aggregate sections unaffected by ASR (a, f, k, p), and from AMBs after 1 (b, g, l, q), 5 (c, h, m, r), 9 (d, i, n, s), and 14 (e, j, o, t) days of testing Quantitative assessment of alkali silica reaction potential of quartz-rich aggregates: comparison… Although the AMBT gives a clear distinction between reactive and non reactive aggregates, it has been criticised in recent studies (e.g., Shayan and Morris 2001;Lindgård et al 2010;Ramos et al 2011). The main disadvantage of this test is the highly aggressive conditions required for the test (1 M NaOH, 80°C) as well as the low sensitivity to The final value for the ASR-affected area was calculated as the difference between the areas exhibiting gray scale (GS) value 0-70 measured on AMBs and the areas exhibiting gray scale value 0-70 measured on aggregate sections a Agg.…”

“…The main disadvantage of this test is the highly aggressive conditions required for the test (1 M NaOH, 80°C) as well as the low sensitivity to The final value for the ASR-affected area was calculated as the difference between the areas exhibiting gray scale (GS) value 0-70 measured on AMBs and the areas exhibiting gray scale value 0-70 measured on aggregate sections a Agg. aggregate section, Q0B quartzite, Q3 chert, Q7C quartz meta-greywacke, Q9 pegmatite quartz, T1 (T5, T9, and T14, respectively) AMB after 1 day (5, 9, and 14 days, respectively) of testing slowly reactive aggregates (e.g., Lindgård et al 2010Lindgård et al , 2012Ramos et al 2011). With the aim of obtaining more accurate results, Ramos et al (2011) and Lindgård et al (2010) suggested prolonging the test period up to 28 days, and modifying the limit between reactive and non-reactive aggregates.…”

“…aggregate section, Q0B quartzite, Q3 chert, Q7C quartz meta-greywacke, Q9 pegmatite quartz, T1 (T5, T9, and T14, respectively) AMB after 1 day (5, 9, and 14 days, respectively) of testing slowly reactive aggregates (e.g., Lindgård et al 2010Lindgård et al , 2012Ramos et al 2011). With the aim of obtaining more accurate results, Ramos et al (2011) and Lindgård et al (2010) suggested prolonging the test period up to 28 days, and modifying the limit between reactive and non-reactive aggregates. Lu et al (2006) showed that crushing the aggregates into a specific granulometry (0.125/5 mm) destroys the original microstructural characteristics of the rocks, resulting in underestimation of the ASR of the rocks in the AMBT.…”

“…Such a methodical approach enables quantification of the ASR potential of aggregates, based on the expansion values of accelerated mortar bars (AMBs) and/or concrete prisms; and also to identify deleterious components of the aggregates, based on their mineral composition and microstructure (e.g., Wigum 1995;Hewlett 2003;Locati et al 2010a;Ramos et al 2011). Another group of methods is based on the leaching of a specific grain size fraction of aggregates in alkaline solution, and on the analysis of the amount of Si 4?…”