Alkali-silica reactivity of different aggregates from mineral and textural characteristics

Abstract

To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse aggregates and the alkali reactivity of these aggregates were systematically investigated. On one hand, petrographic examination of aggregates, combined with X-ray diffraction analysis, chemical analysis, scanning electron microscopy, was conducted for analyzing their mineralogy and texture. It was found that not only mineral characteristics, but also their interior structure would affect their potential alkali-silica reactivity. Furthermore, the alkali-silica reactivity of aggregates is due to their mineral compositions, such as containing different alkali-reactive minerals, while, different stuctures of those aggregates with similar minerals affect their reactivity to some extent. There are some amount of micro-aperture and cracks across the quartz in the aggregate, which may become the natural accesses for Na⁺, K⁺, and OH⁻ ions to intrude in the mortar or concrete during the process of alkali-silica reaction. Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test. It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.

Keywords

petrographic examination of aggregates / study of thin sections / x-ray diffraction analysis / chemical analysis / scanning electron microscopy

References

[1] Mo X. Y., Lu D. Y., Xu Z. Z. Mechanism of Chemical Admixtures in Inhibiting Alkali-silica Reaction and Its Research Progress[J]. J. Nanjing Univ. Technol., 2000, 22(3): 72-77.

[2] Bulteel D., Garcia-Diaz E., Vernet C., . Alkali-silica Reaction-a Method to Quantify the Reaction Degree[J]. Cem. Con. Res., 2002, 32(8): 1199-1206.

[3] Rivard P., Ollivie J. P., Ballivy G. Characterization of the ASR Rim-application to the Postsdam Sandstone[J]. Cem. Con. Res., 2002, 32(8): 1259-1267.

[4] Fournier B., Berube M. A. Alkali-aggregate Reaction in Concrete: A Review of Basic Concepts and Engineering Implications[J]. Can. J. Civ. Eng., 2000, 27(2): 167-191.

[5] Amo D. G., Perez B. C. Diagnosis of the Alkali-silica Reactivity Potential by Means of Digital Image Analysis of Aggregate Thin Sections[J]. Cem. Con. Res., 2001, 31(10): 1449-1454.

[6] Marfil S. A., Maiza P. J. Deteriorated Pavements Due to the Alkali-silica Reaction-a Petrographic Study of Three Cases in Argentina[J]. Cem. Con. Res., 2001, 31(7): 1017-1021.

[7] Wakizaka Y. Alkali-silica Reactivity of Japanese Rocks[J]. Eng. Geo., 2000, 56(1–2): 211-221.

[8] The standard of the Association of Chinese Construction Standardization. A Rapid Test Method for Determining the Alkali Reactivity of Sands and Rocks[S]. CECS48-93, 1993(in Chinese)

[9] Mo X. Y., Yu C. J., Xu Z. Z. Long-term Effectiveness and Mechanism of LiOH in Inhibiting Alkali Silica Reaction[J]. Cem. Con. Res., 2003, 33(1): 115-119.

[10] Mo X. Y. Long-term Effectiveness and Mechanisms of Chemical Admixtures in Inhibiting Alkali-Silica Reaction[D], 2001. Nanjing: Nanjing University of Chemical Technology.

[11] Mo X. Y., Xu Z. Z., Wu K. R., . Alkali-silica Reaction Inhibited by LiOH and Its Mechanism[J]. J. Wuan Univ. Tech. -Mater. Sci. Edi., 2003, 18(1): 13-16.

[12] Feng N. Q., Hao T. Y., Feng X. X. Study of the Alkali Reactivity of Aggregates Used in Beijing[J]. Mag. Con. Res., 2002, 54(4): 233-237.

[13] Broekmans M. A. T. M. Structural Properties of Quarts and Their Potential Role for ASR[J]. Mater. Charact., 2004, 53: 129-140.

[14] Mo X. Y., Jin T. S., Li G., . Alkali-aggregate Reaction Suppressed by Chemical Admixture at 80 °C[J]. Con. Build. Mater., 2005, 19: 473-479.

[15] Deng M, Lan X H, Xu Z Z, et al. Petrographic Characteristics and Distributions of Reactive Aggregates in China[C]. In: Tang M S, Deng M, eds. Proc. of 12th International Conference on Alkali-Aggregate Reaction in Concrete. Beijing, China, 2004

[16] Mo X. Y. Laboratory Study of LiOH in Inhibiting Alkali-silica Reaction at 20 °C: A contribution[J]. Cem. Con. Res., 2005, 35(3): 499-504.

[17] Mo X. Y., Xu Z. Z., Wu K. R., . Effectiveness of LiOH in Inhibiting Alkali-aggregate Reaction and Its Mechanism[J]. Mater. Struc., 2005, 38(275): 57-61.

[18] Wakizaka Y. Reactivity of Rocks and Minerals in Alkali Solution[J]. J. Res., 1998, 34: 146