scholarly journals Influence of the Quartz Deformation Structures for the Occurrence of the Alkali–Silica Reaction

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1692 ◽  
Author(s):  
Francieli Tiecher ◽  
Renata Florindo ◽  
Geilma Vieira ◽  
Márcia Gomes ◽  
Denise Dal Molin ◽  
...  
Keyword(s):  
Atomic Scale ◽  
Alkali Silica Reaction ◽  
Deformation Bands ◽  
Deformation Degree ◽  
Deformation Structures ◽  
Before And After ◽  
Accelerated Mortar Bar Test ◽  
High Alkalinity ◽  
Mortar Bar ◽  
Alkali Hydroxides

Defects in the crystalline structure of quartz facilitate the connection with the alkali hydroxides, since under a high alkalinity condition (e.g., in concrete), the Si-O bonds of quartz are easily broken. This study set out to investigate the influence of the deformation structures of quartz on its susceptibility to the alkali–silica reaction. A granite, a protomylonite, and a mylonite were selected for this study. Using optical microscopy, the quartz grains contained in these rocks were quantified and their texture characterized. The quartz samples extracted from the rocks were analyzed by magnetic nuclear resonance, to evaluate their potential for dissolving silica as well as changes in their atomic scale before and after the reaction with alkali hydroxides. These analyses were compared with the results of the accelerated mortar bar test. The study showed that the quartz with intense undulatory extinction and deformation bands denotes the most favorable condition to the development of the alkali–silica reaction. However, on an atomic scale, the slightly deformed grains were highly prone to react. Thus, in a high alkalinity condition, over a long period of time, any quartz tends to develop the alkali–silica reaction, regardless of the deformation degree of the grain.

How does fly ash mitigate alkali–silica reaction (ASR) in accelerated mortar bar test (ASTM C1567)?

2013 ◽  
Vol 37 ◽  
pp. 143-153 ◽  
Author(s):  
Seyed M.H. Shafaatian ◽  
Alireza Akhavan ◽  
Hamed Maraghechi ◽  
Farshad Rajabipour
Keyword(s):  
Fly Ash ◽  
Alkali Silica Reaction ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

Effect of the Composite of Fly Ash and Slag on Alkali-Silica Reaction

2014 ◽  
Vol 936 ◽  
pp. 1428-1432
Author(s):  
Tong Chao Liu ◽  
Bo Xiao ◽  
Gu Hua Li ◽  
Nian Hong Luo ◽  
Long Sheng Zhang
Keyword(s):  
Fly Ash ◽  
Inhibitory Effect ◽  
Alkali Silica Reaction ◽  
Alkali Aggregate Reaction ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar ◽  
Better Than

The study used the method of accelerated mortar bar test to study alkali aggregate reaction (ASR) with sandstone aggregate. Both fly ash and slag can inhibit the expansion of mortar bar. Results show that 50% slag can inhibit ASR reluctantly, but 10% fly ash and 20% slag can inhibit ASR very well, and the inhibitory effect of fly ash is far better than slag. Because of the high content of CaO in slag, it has inhibit and promote aspects, when the ASR is fierce, slag can inhibit ASR, otherwise slag can promote ASR.

scholarly journals Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

2015 ◽  
Vol 10 (2) ◽  
pp. 17-27 ◽  
Author(s):  
Aref M. al-Swaidani ◽  
Mohammad K. Baddoura ◽  
Samira D. Aliyan ◽  
Walid Choeb
Keyword(s):  
Compressive Strength ◽  
Alkali Resistance ◽  
Alkali Silica Reaction ◽  
Ongoing Research ◽  
Chemical Test ◽  
Concrete Aggregates ◽  
Basaltic Rocks ◽  
Naoh Solution ◽  
Accelerated Mortar Bar Test ◽  
Mortar Bar

Abstract The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction). Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289) and accelerated mortar bar test (ASTM C1260) have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida’a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

Effect of Slate Powder on Mineral Admixtures in Suppressing Alkali-Silica Reaction of Slate Aggregate

2012 ◽  
Vol 204-208 ◽  
pp. 4201-4206
Author(s):  
Xian Xiao Peng ◽  
Gu Hua Li ◽  
Wu Huang ◽  
Yuan Fu Li ◽  
Xiao Chun He
Keyword(s):  
Fly Ash ◽  
Mineral Admixtures ◽  
Alkali Silica Reaction ◽  
Steam Curing ◽  
Durability Design ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Curing Method ◽  
Mortar Bar ◽  
Powder Content

In order to study the effects of slate powder on mineral admixtures in suppressing ASR of slate aggregate, refer to the following methods: accelerated mortar bar test in “Standard for Constructional Quality Acceptance of Railway Concrete Engineering” TB10424-2010 and “Durability Design of Railway Concrete Structures” TB10005-2010, as well as an improved steam curing method. The text has studied the expansion of the specimens that are made from slate aggregate with different powder contents and specimens using slate powder as admixtures. The results show : When powder content in aggregate is less than 20%, it dose not have adverse effects; ASR of high-activity slate aggregate can be suppressed by using 30% fly ash and 5% silica fume as mineral admixtures; when the mineral admixtures are effective, a certain amount of powder mixed with admixtures can contribute to suppression; the main mechanism that slate powder can suppress ASR is that alkali in concrete can be consumed and physically diluted by slate powder.

Study on Experiments of Matekaolin in Relation to Alkali-Silica Reaction

2014 ◽  
Vol 629-630 ◽  
pp. 528-533
Author(s):  
Hong Yi Zhou ◽  
Fu Hai Li ◽  
Si Yin Chen ◽  
Xiao Gang Zhao ◽  
Gu Hua Li
Keyword(s):  
Fly Ash ◽  
Significant Influence ◽  
Sem Analysis ◽  
Alkali Silica Reaction ◽  
Result Show ◽  
Glass Aggregate ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

The influence of the content of matekaolin powder and fly ash in cement on controlling ASR was evaluated using Accelerated Mortar Bar Test (AMBT). Replacing cement with matekaolin powder to the extent of 5%,10%,15%,20%,25%,and with fly ash to the extent of 10%,20%,30%,35%,40%, 45% respectively. The result show that matekaolin powder and fly ash both can control Alkali-aggregate activity but to different degrees. Small amount of metakaolin powder exerts significant influence, whereas only when the proportion of fly ash is up to 35%, can it control ASR effectively. The effect and mechanism of the control of the extension of glass aggregate activity was studied by means of SEM analysis.

Sign in / Sign up

Export Citation Format

Share Document