scholarly journals EFFECT OF AGGREGATE COEXISTING WITH REACTIVE AGGREGATE ON ASR EXPANSION

2021 ◽  
Vol 74 (1) ◽  
pp. 235-242
Author(s):  
Atsushi TERAMOTO ◽  
Takaaki OHKUBO
Keyword(s):  
Reactive Aggregate

Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part II: Application to nonreinforced concrete specimens exposed outside

2004 ◽  
Vol 31 (6) ◽  
pp. 997-1011 ◽  
Author(s):  
Nizar Smaoui ◽  
Benoit Fournier ◽  
Marc-André Bérubé ◽  
Benoit Bissonnette ◽  
Benoit Durand
Keyword(s):  
Relative Humidity ◽  
Alkali Silica Reaction ◽  
Test Surface ◽  
Good Relationship ◽  
Surface Cracking ◽  
Reactive Aggregate ◽  
Concrete Blocks ◽  
Relationship Coefficient ◽  
Concrete Elements ◽  
Made In

In part I, relationships were obtained in the laboratory between the expansion due to alkali-silica reaction (ASR) and (i) the "stiffness damage test" (SDT), (ii) the "damage rating index" (DRI), and (iii) the surface cracking of the concrete. These tests were conducted on nonreinforced concrete blocks and cylinders made with various reactive aggregates and stored at 38 °C and >95% relative humidity. The objective of part II was to verify the validity of the relationships from part I for concrete elements made in the laboratory but exposed outside. On average for the 51 blocks and 14 slabs tested, the surface cracking increased with ASR expansion and approached the measured expansion in the case of the most severely exposed sections of the specimens tested. The ratio between the expansion estimated from the surface cracking and the measured expansion varied greatly from one specimen to another (between 0 and 4.3), however. Taking into account the type of reactive aggregate involved did not explain the situation. Despite a variety of reactive aggregates, a quite good relationship (coefficient of linear regression R2 = 0.89) was obtained between the DRI and the ASR expansion for the six blocks cored and tested for DRI and SDT. This relationship is significantly different from those obtained in the laboratory, however. Moreover, the exposed concretes clearly differ from the laboratory concretes regarding the most important defects observed in the DRI test. As in the laboratory, the results obtained from the SDT seem to depend on the type of reactive aggregate involved. Nevertheless, this test globally supplied results with the best agreement with the measured expansion.Key words: aggregates, alkali–silica reaction, concrete expansion, damage rating index, petrography, stiffness damage test, surface cracking.

Alkali-aggregate reactions in Ontario

2000 ◽  
Vol 27 (2) ◽  
pp. 246-260 ◽  
Author(s):  
Chris Rogers ◽  
P E Grattan-Bellew ◽  
R Doug Hooton ◽  
J Ryell ◽  
M DA Thomas
Keyword(s):  
Preventive Measures ◽  
Selective Extraction ◽  
Test Methods ◽  
Concrete Cracking ◽  
Reactive Aggregate ◽  
Supplementary Cementing Materials ◽  
The Past ◽  
Alkali Aggregate Reaction

In Ontario, two types of alkali-aggregate reaction exist. Each type is evaluated using different tests. Over the past few years, new tests have been introduced to replace some existing test methods. The new tests are faster and more reliable. Preventive measures such as the use of low-alkali cement and supplementary cementing materials, while they are effective, have not been extensively used with reactive aggregate in Ontario. Beneficiation or selective extraction is used with some potentially reactive aggregates.Key words: alkali-aggregate reaction, concrete, cracking, Ontario, structures.

Le barrage Sartigan dans la Beauce (Québec), Canada : un cas-type de détérioration du béton par des réactions alcalis–granulats

1987 ◽  
Vol 14 (3) ◽  
pp. 372-380 ◽  
Author(s):  
Marc-André Bérubé ◽  
Benoit Fournier
Keyword(s):  
Cement Paste ◽  
High Humidity ◽  
Reactive Aggregate ◽  
Fracture Surfaces ◽  
Alkali Aggregate Reactivity ◽  
High Alkali ◽  
Aggregate Particles

The Sartigan dam, a concrete ice-retention dam built in 1967 along the Chaudière River, near Saint-Georges de Beauce, Quebec, Canada, shows numerous megascopic and microscopic signs of alkali–aggregate reactivity of the alkali–silica type (expansion, polygonal map cracking, silico-alkaline gels, looseness of cement paste – aggregate bonds, characteristic rims on fracture surfaces through coarse reactive aggregate particles, etc.). Besides, the three conditions considered as essential to promote these reactions in concrete have been satisfied in this case: the use of a high-alkali cement, conditions of high humidity reinforced by frequent wetting–drying cycles, and aggregates considered as potentially alkali-reactive in concrete (rhyolitic tuffs with a devitrified matrix rich in microcrystalline quartz).

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