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Study of the alkali-aggregate reaction on concrete prisms
Cement and Concrete Resenreh, Vol. 24, No. 3, pp. 473--478, 1994
Copyright © 1994 Elsevier Science Ltd Printed in the USA. All fights reserved 0008-8846/94 $6.00 + .00
Pergamon
S T U D Y OF THE ALKALI-AGGREGATE REACTION O N C O N C R E T E PRISMS.
L. CURTIL*, M.F. HABITA**. * LGCHE, 1UT Genie Civil, 69622 VII J.EURBANNE CEDEX, FRANCE. ** UNIVERSITE D'ANNABA, ALGERIE. (Communicated by M. Moranville-Regourd) (Received June 11, 1993)
ABSTRACT These experiments were conducted by M.F. HABITA (1,2), in his thesis, on different types of concrete specimens aiming to study the structural effects of the alkali-aggregate reaction on the mechanical behavior of concrete. Microscopic observaUons were carried out concurrently. In this paper, we deal only with work carried out on concrete prisms 14 x 14 x 56 cm : measurements of expansion, measurements of tensile strength and observation of thin sections by means of a polarizing microscope. Introduction
The phenomenon of alkali-aggregate reaction which takes place within hydraulic concrete is caused by a chemical interaction between the basic cement pore solution and the amorphous siliceous aggregates. This is often the cause of concrete degradation. The disorders due to this reaction are sometimes very large (very high swelling pressure at the cement paste-aggregate interface, exp.amion and cracking of construction works) and can lead to considerable damage to civil engmeenng structures. The study of alkali-aggregate reaction is complicated. Indeed, mortars or concretes are heterogeneous systems in which many reactions of different speeds are superimposed. The problem is also to isolate the products of reaction and mechanisms for study. The experiments are conducted by M.F. HABITA (1,2), as part of his thesis, on concrete sms 14x14x56 era. e aggrel~ates used are principally micaschists and the cement is an OPC 55 with 0.917% Na20 eqmvalent (Na20 + 0.658 1(20 ). Four kinds of concrete mix are maffe : - Concrete R standard with 0.917% Na20 equivalent stored at 21YC ; Concrete A with 0.917% Na20 equivalent stored at 40°C and 100% Relative Humidity ; Concrete B with 1.5% N a 2 0 equivalent (addition of NaOH to the water) stored at 40°C and 100% R H ; - Concrete C with 1.5% Na20 equivalent (addition of KOH to the water) stored at 40°C and 100% RH.
~
473
474
L. Curtil and M.F. Habita
Vol. 24, No. 3
The microscopic observations were carried out on thin sections of concrete at periods of one month, three months, six months and one year. The structural effects of the alkali-aggregate reaction on the mechanical behavior of concrete were studied by measurements of expansion and measurements of tensile strength. Studv of the alkali-a2m'e2ate reaction by_nolarizing microscQPe After studying the behavior of concrete towards carbonation by use of a polarizing microscope (3), this excellent and less expensive analysis technique was also utilized for investigating alkali-aggregate reaction. From now on, it is taken for granted that the polarizing microscope is a very useful investigative method in the inspection of concrete (4). Many countries have published recommendations for the prevention of damage by the alkali-aggregate reaction and the use of the polayi~. ~gmicroscope is advocated (5,6,7,8). Indeed, the polarizing microscope enables us a petrographical examination of thin sections of concrete and determination of the degree of degradation due to AAR : on one hand, before or after the reaction, the determination of potential reactive aggregates (ASTM C295) can be interesting (Figures 1.1-1.2) and on the other hand, after the reaction, the polarizing microscope makes it possible to determine the degree of degradation and provided proof of presence of reactive aggregates and products of AAR (Figures 1.5-1.8). Samples investigated Thin sections (thirty microns thick) are made periodically on the four kinds of concrete prisms 14x14x56 cm. The aggregates used in this study are micaschists (Figures 1.1-1.2) with potential reactive minerals:quartz with undulatory extinction, microcristaUine quartz and deteriorated feldspar and mica. Study of prisms of concrete by polarizing microscope Thin sections show the presence of microcracks and products of AAR. - All types of one month old concrete have no microcrack due to AAR but have shrinkage microcracks. These microcracks are due to shrinkage of 0.008 % during the first three weeks. - Three month old concretes react in two ways : concretes with 0.917 % Na20 equivalent (concretes R and A) show aggregates surrounded by shrinkage microcracks (Figures 1.31.4) ; concretes with 1.5 % Na20 equivalent (concretes B and C) have varying degrees of microcracking in the aggregates. This fact means that internal chemical reactions have started. Confirmation of the presence of gel, a product of AAR, was given by SEM on concretes B and C. - Six month old concretes are different. Indeed, concrete A (0.917 % Na20 equivalent and storage at 40°C and 100% RH) shows some signs of AAR (some microcracks in the aggregates). Concretes with 1.5 % Na20 equivalent (B and C) have more numerous microcracks. - One year old concretes are similar to those aged six months but concretes B and C have very numerous microcracks in the aggregates. These microcracks go across aggregates and cement paste (Figures 1.5-1.6). Some mlcrocracks are filled with gel, a product of internal chemical reactions (Figures 1.7-1.8). Study of the alkali-agm-egate reaction bv measurements of exnansion Concrete expansion is a frequent disorder due to this reaction. So measurements of expansion were carried out on concrete prisms periodically every week for one year (Table 1, Figure 2). - One month 01d concretes have a very low expansion of the order of 0.02%. During the first three weeks we can observe in figure 2 a negative expansion due to shrinkage. - Three month old concretes have a differential expansxon. - Expansion of six month old concretes increases.
Vol. 24, No. 3
ALKALI-AGGREGATEREACTION, MECHANICALBEHAVIOR,MICROSCOPY
1.1
475
1.2 0.16mm
I
1.3
I
1.4 0.42ram
I
1.5
t
1.6 0.42ram
l
1.7
1
1.8 0.42tara
A
F I G 1 : Polarizing Microscope micrographs of aggregate.
1.1. a potential reactive aggregate : the rnicaschist used in this study with crossed olars. 1.2. schema of 1.1 : we can observe a layer of mica (muscovite : / / / / / ) etween two layers of microcristalline quartz andquartz with undulatory extinction (Q) with some scattered mica. Polarizing Microscope micrographs of concrete. 1.3. aggregate surrounded by shrinkage microcracks under plane-polarized light. 1.4. schema of 1.3 : we can observe aggregates (A) surrounded by shrinkage microcracks (in black). 1.5. microcracks (in h"ght ; 1.6 : in black) due to AAR which go across reactive aggregates (A) and cement paste under plane-polarized light. 1.6. schema of 1.5. 1.7. exsudation of gel (in light ; H : in black) from a reactive aggregate (A) under plane-polarized light. 1.8. schema of 1.7.
~
476
L. Curtil and M.F. Habita
Vol. 24, No. 3
TABLE 1 : Measured expansion (%) on the concrete prisms 1 month
3 months
6 months
I year
concrete R
- 0.045%
- 0.06%
- 0.06%
- 0.06%
concrete A
+ 0.02%
+ 0.08%
+ 0.13%
+ 0.16%
concrete B
+ 0.01%
+ 0.1%
+ 0.35%
+ 0.39%
concrete C
+ 0.02%
+ 0.15%
+ 0.27%
+ 0.33%
- One year old concretes are similar to those aged six months. We can observe that concrete R always shows shrinkage only. Concrete C reacts more rapidly in comparison with concrete B. This trend is inverted after four months. Three month old concretes C and B show signs of AAR. Six month old concretes (A and C) have varying degrees of microcracldng in the aggregates. Therefore an expansion value of 0.1% means that internal chemical reactions have started. Most of the measurements of expansion were carried out on mortars. Canadians are given a limit value of expansion for concrete prisms made according to norm ACNOR CAN3 A23, 2.14A (concrete prisms 7.5x7.5x30 cm stored at 38°C and 100% RH). In that case, the limit value of reactivity is 0.04% after six months. Experiments conducted by M.F. HABITA in his thesis (1) on concrete prisms 7x7x28 and 14x14x56 cm have proved that there is a factor of 4 between expansion of concrete prisms 7x7x28 and 14x14x56 probably due to the factor of 4 of the section. So we can estimate that the limit value of expansion on concrete prisms 14x14x56 cm stored at 40°C and 100%RH is 0.16% after six months (Figure 2). Study of the alkali-agm'egate reaction by measurements of tensile s t r e n ~ h
Tensile strengths are measured on concrete prisms periodically (Figure 3). Concrete R has a constant tensile strength. Other concretes (A, B and C) show a decrease of tensile strength in time. The decrease of the tensile strength of one year old concrete B reachs 37%, concretes C and A reach 23%. Tensile strength is a very sensitive criterion of the alkali-aggregate reaction. Conclusion
The findings of this study are : - The polarizing mtcroscope is a tool of interest for investigating alkali-aggregate reaction in concrete. Indeed concrete is a heterogeneous system and the use of a polarizing microscope allows us to observe a microscopic phenomenon with macroscopxc interferences. This technique determines precisely the cause of degradation and more importantly the degree and the future development of this degradation (characteristics of the paste and the aggregates, the grade of microcracking, the contact zone between paste and the grains, the presence of borders of reaction, products of reaction...). A technical problem resides in the preparation of thin sections. In fact, gels are not always present in thin sections because they are dissolved when the sections are prepared. Gels have to be fixed then stained (10,11,12,13,14). - Measurements of expansion show a very good correlation between the type of cracking observed by the polarizing microscope and the percentage of expansion. An expansion value of 0.1% means that internal chemical reactions have started: we can observe microcraks in the aggregates and presence of gels. - Expansion rates of concrete are lower than those of other authors (15). Indeed expansion rate of concrete reachs sometimes 1 to 1.5% with very reactive aggregates (opal or "fused silica"). But these aggregates are unusual in concrete. The micaschist used i n this study is an usual polyphasic rock whose expansion develops at a moderate rate. - Measunng of tensile strength is a very sensitive criterion of AAR and this measurement is very easy to carry out.
Vol. 24, No. 3
ALKALI-AGGREGATE REAC'rlON,MECHANICALBEHAVIOR,MICROSCOPY
477
4 3.5 3 2.5
o
2
I I
1.5 1
0.5 0 5
10
15
20
25
30
35
40
45
-0.5
50
55
TIME (WEEKS)
-1
-- 20"C (Concrete R) FIG 2 : Measured expansion on the concrete prisms (14x14x56cm).
+ 4-0"C 1007, HR O.gX Nc]20 Eq (Concrete A)
(- ! - : limit value of expansion I = 0.16 % after six months)
,--X--40"C 100~ HR 1.5,X l"la20 Ca "DOP NaOH"
(Concrete B)
8' 40"C 100,~ HR 1.Sg Na20 Eq "DOP KOH"
(Concrete C)
%" 6 m
5
~.1 [-.,
4
,.4
3
z a.l [.-,
2 1 o
|
I
2
4
I
I
I
6 8 10 TIME (MONTHS)
I
12
I
14
FIG 3 : Tensile strength on the concrete prisms (14x14x56cm).
478
L. Curtil and M.F. Habita
Vol. 24, No. 3
References
. . .
.
5. 6. 7. .
. 10. 11. 12. 13. 14. 15.
M.F. HABITA. "Contribution /i l'6tude de l'incidence de l'alcali-r6action sur le comportement m6carlique des poutres en b6ton arm6", Universit6 Claude Bernard, novembre 1992, 200 pages. M.F. HABITA, M. BROUXEL &~). PRIN. "Alkali-Aggregate Reaction Structural Effects : an experimental study", 9tu International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992,p403-410. L. CURTIL, J. GIELLY & M. MURAT. "the polarizing microscope: a tool of interest for investigation on concrete; application to carbonation", Cement and Concrete Research, vol 23, n°2, in press. J. Prlq~. "The role of petrography in the investigation of concrete and its constituents", Concrete 1987, vol 21, n°'/. Recommandations provisoires pour la pr6vention des d6sordres dus ~t l'alcalir6action - Laboratoire Central des Ponts et Chauss6es - Janvier 1991. Alkali-silica reaction jgeneral recommendations and guidance in the specification of building and civil engineering works - Irish Concrete Society - Dublin - 1991. D. BRAGG & K. FOSTER. "Relationship between petrography .and results of alkali-reactivity testing, samples from Newfoundland, Canada", 9tta International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p127-135. P.A. DAHL, I. MELAND & V. JENSEN. "N~rwegian experience with different test methods for Alkali-Aggregate Reactivity", 9 tu International Conference on AlkaliAggregate Reaction in Concrete, London, 1992, p224-230. R.G. SIBBICK & C;L. PAGE. "Susceotibility o f various UK Aggregates to AlkaliAggregate Reaction, 9m International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p980-987. G. WEST & R. SIBBICIC "Alkali-silica reaction in roads", Concrete, April 1988 and May 1989. B. LAGERBLAD & J. TRAGARDH. "Slowly reactir/g aggregates in Sweden mechanism and conditions for reactivity in concrete", 9 m International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p570-578. I. SIMS, B. HUNT & B.F. MIGLIO. "Quantifying microscopical examinations of concrete for AAR and other durability aspects", Proceedings of the G.M. Idorn Durability Symposium, ACI Convention, Holm J. (Ed.), Toronto, 1990. K.T. ANDERSEN & N. THAULOW. 'q'he study of Alkali Silica Reactions in concrete by use of fluorescent thin sections", ASTM STP 1061 "Petrography applied to concrete and concrete aggregates", Erlin/Stark,, . editors, Philadelphia," USA. N. THAULOW, R.J. LEE & J. HOLM. An integrated optical SEM method for the identification of Alkali Silica Reaction in concrete sleepers", Proc. Int. symposium on precast concrete railway sleepers, 1991, Madrid, Spain. R.N. SWAMY & M.M. AL-ASALI. "Effect of alkali-silica reaction on the structural behavior of reinforced concrete beams", ACI Structural Journal, 1989, v.86, p451459.
Copyright © 1994 Elsevier Science Ltd Printed in the USA. All fights reserved 0008-8846/94 $6.00 + .00
Pergamon
S T U D Y OF THE ALKALI-AGGREGATE REACTION O N C O N C R E T E PRISMS.
L. CURTIL*, M.F. HABITA**. * LGCHE, 1UT Genie Civil, 69622 VII J.EURBANNE CEDEX, FRANCE. ** UNIVERSITE D'ANNABA, ALGERIE. (Communicated by M. Moranville-Regourd) (Received June 11, 1993)
ABSTRACT These experiments were conducted by M.F. HABITA (1,2), in his thesis, on different types of concrete specimens aiming to study the structural effects of the alkali-aggregate reaction on the mechanical behavior of concrete. Microscopic observaUons were carried out concurrently. In this paper, we deal only with work carried out on concrete prisms 14 x 14 x 56 cm : measurements of expansion, measurements of tensile strength and observation of thin sections by means of a polarizing microscope. Introduction
The phenomenon of alkali-aggregate reaction which takes place within hydraulic concrete is caused by a chemical interaction between the basic cement pore solution and the amorphous siliceous aggregates. This is often the cause of concrete degradation. The disorders due to this reaction are sometimes very large (very high swelling pressure at the cement paste-aggregate interface, exp.amion and cracking of construction works) and can lead to considerable damage to civil engmeenng structures. The study of alkali-aggregate reaction is complicated. Indeed, mortars or concretes are heterogeneous systems in which many reactions of different speeds are superimposed. The problem is also to isolate the products of reaction and mechanisms for study. The experiments are conducted by M.F. HABITA (1,2), as part of his thesis, on concrete sms 14x14x56 era. e aggrel~ates used are principally micaschists and the cement is an OPC 55 with 0.917% Na20 eqmvalent (Na20 + 0.658 1(20 ). Four kinds of concrete mix are maffe : - Concrete R standard with 0.917% Na20 equivalent stored at 21YC ; Concrete A with 0.917% Na20 equivalent stored at 40°C and 100% Relative Humidity ; Concrete B with 1.5% N a 2 0 equivalent (addition of NaOH to the water) stored at 40°C and 100% R H ; - Concrete C with 1.5% Na20 equivalent (addition of KOH to the water) stored at 40°C and 100% RH.
~
473
474
L. Curtil and M.F. Habita
Vol. 24, No. 3
The microscopic observations were carried out on thin sections of concrete at periods of one month, three months, six months and one year. The structural effects of the alkali-aggregate reaction on the mechanical behavior of concrete were studied by measurements of expansion and measurements of tensile strength. Studv of the alkali-a2m'e2ate reaction by_nolarizing microscQPe After studying the behavior of concrete towards carbonation by use of a polarizing microscope (3), this excellent and less expensive analysis technique was also utilized for investigating alkali-aggregate reaction. From now on, it is taken for granted that the polarizing microscope is a very useful investigative method in the inspection of concrete (4). Many countries have published recommendations for the prevention of damage by the alkali-aggregate reaction and the use of the polayi~. ~gmicroscope is advocated (5,6,7,8). Indeed, the polarizing microscope enables us a petrographical examination of thin sections of concrete and determination of the degree of degradation due to AAR : on one hand, before or after the reaction, the determination of potential reactive aggregates (ASTM C295) can be interesting (Figures 1.1-1.2) and on the other hand, after the reaction, the polarizing microscope makes it possible to determine the degree of degradation and provided proof of presence of reactive aggregates and products of AAR (Figures 1.5-1.8). Samples investigated Thin sections (thirty microns thick) are made periodically on the four kinds of concrete prisms 14x14x56 cm. The aggregates used in this study are micaschists (Figures 1.1-1.2) with potential reactive minerals:quartz with undulatory extinction, microcristaUine quartz and deteriorated feldspar and mica. Study of prisms of concrete by polarizing microscope Thin sections show the presence of microcracks and products of AAR. - All types of one month old concrete have no microcrack due to AAR but have shrinkage microcracks. These microcracks are due to shrinkage of 0.008 % during the first three weeks. - Three month old concretes react in two ways : concretes with 0.917 % Na20 equivalent (concretes R and A) show aggregates surrounded by shrinkage microcracks (Figures 1.31.4) ; concretes with 1.5 % Na20 equivalent (concretes B and C) have varying degrees of microcracking in the aggregates. This fact means that internal chemical reactions have started. Confirmation of the presence of gel, a product of AAR, was given by SEM on concretes B and C. - Six month old concretes are different. Indeed, concrete A (0.917 % Na20 equivalent and storage at 40°C and 100% RH) shows some signs of AAR (some microcracks in the aggregates). Concretes with 1.5 % Na20 equivalent (B and C) have more numerous microcracks. - One year old concretes are similar to those aged six months but concretes B and C have very numerous microcracks in the aggregates. These microcracks go across aggregates and cement paste (Figures 1.5-1.6). Some mlcrocracks are filled with gel, a product of internal chemical reactions (Figures 1.7-1.8). Study of the alkali-agm-egate reaction bv measurements of exnansion Concrete expansion is a frequent disorder due to this reaction. So measurements of expansion were carried out on concrete prisms periodically every week for one year (Table 1, Figure 2). - One month 01d concretes have a very low expansion of the order of 0.02%. During the first three weeks we can observe in figure 2 a negative expansion due to shrinkage. - Three month old concretes have a differential expansxon. - Expansion of six month old concretes increases.
Vol. 24, No. 3
ALKALI-AGGREGATEREACTION, MECHANICALBEHAVIOR,MICROSCOPY
1.1
475
1.2 0.16mm
I
1.3
I
1.4 0.42ram
I
1.5
t
1.6 0.42ram
l
1.7
1
1.8 0.42tara
A
F I G 1 : Polarizing Microscope micrographs of aggregate.
1.1. a potential reactive aggregate : the rnicaschist used in this study with crossed olars. 1.2. schema of 1.1 : we can observe a layer of mica (muscovite : / / / / / ) etween two layers of microcristalline quartz andquartz with undulatory extinction (Q) with some scattered mica. Polarizing Microscope micrographs of concrete. 1.3. aggregate surrounded by shrinkage microcracks under plane-polarized light. 1.4. schema of 1.3 : we can observe aggregates (A) surrounded by shrinkage microcracks (in black). 1.5. microcracks (in h"ght ; 1.6 : in black) due to AAR which go across reactive aggregates (A) and cement paste under plane-polarized light. 1.6. schema of 1.5. 1.7. exsudation of gel (in light ; H : in black) from a reactive aggregate (A) under plane-polarized light. 1.8. schema of 1.7.
~
476
L. Curtil and M.F. Habita
Vol. 24, No. 3
TABLE 1 : Measured expansion (%) on the concrete prisms 1 month
3 months
6 months
I year
concrete R
- 0.045%
- 0.06%
- 0.06%
- 0.06%
concrete A
+ 0.02%
+ 0.08%
+ 0.13%
+ 0.16%
concrete B
+ 0.01%
+ 0.1%
+ 0.35%
+ 0.39%
concrete C
+ 0.02%
+ 0.15%
+ 0.27%
+ 0.33%
- One year old concretes are similar to those aged six months. We can observe that concrete R always shows shrinkage only. Concrete C reacts more rapidly in comparison with concrete B. This trend is inverted after four months. Three month old concretes C and B show signs of AAR. Six month old concretes (A and C) have varying degrees of microcracldng in the aggregates. Therefore an expansion value of 0.1% means that internal chemical reactions have started. Most of the measurements of expansion were carried out on mortars. Canadians are given a limit value of expansion for concrete prisms made according to norm ACNOR CAN3 A23, 2.14A (concrete prisms 7.5x7.5x30 cm stored at 38°C and 100% RH). In that case, the limit value of reactivity is 0.04% after six months. Experiments conducted by M.F. HABITA in his thesis (1) on concrete prisms 7x7x28 and 14x14x56 cm have proved that there is a factor of 4 between expansion of concrete prisms 7x7x28 and 14x14x56 probably due to the factor of 4 of the section. So we can estimate that the limit value of expansion on concrete prisms 14x14x56 cm stored at 40°C and 100%RH is 0.16% after six months (Figure 2). Study of the alkali-agm'egate reaction by measurements of tensile s t r e n ~ h
Tensile strengths are measured on concrete prisms periodically (Figure 3). Concrete R has a constant tensile strength. Other concretes (A, B and C) show a decrease of tensile strength in time. The decrease of the tensile strength of one year old concrete B reachs 37%, concretes C and A reach 23%. Tensile strength is a very sensitive criterion of the alkali-aggregate reaction. Conclusion
The findings of this study are : - The polarizing mtcroscope is a tool of interest for investigating alkali-aggregate reaction in concrete. Indeed concrete is a heterogeneous system and the use of a polarizing microscope allows us to observe a microscopic phenomenon with macroscopxc interferences. This technique determines precisely the cause of degradation and more importantly the degree and the future development of this degradation (characteristics of the paste and the aggregates, the grade of microcracking, the contact zone between paste and the grains, the presence of borders of reaction, products of reaction...). A technical problem resides in the preparation of thin sections. In fact, gels are not always present in thin sections because they are dissolved when the sections are prepared. Gels have to be fixed then stained (10,11,12,13,14). - Measurements of expansion show a very good correlation between the type of cracking observed by the polarizing microscope and the percentage of expansion. An expansion value of 0.1% means that internal chemical reactions have started: we can observe microcraks in the aggregates and presence of gels. - Expansion rates of concrete are lower than those of other authors (15). Indeed expansion rate of concrete reachs sometimes 1 to 1.5% with very reactive aggregates (opal or "fused silica"). But these aggregates are unusual in concrete. The micaschist used i n this study is an usual polyphasic rock whose expansion develops at a moderate rate. - Measunng of tensile strength is a very sensitive criterion of AAR and this measurement is very easy to carry out.
Vol. 24, No. 3
ALKALI-AGGREGATE REAC'rlON,MECHANICALBEHAVIOR,MICROSCOPY
477
4 3.5 3 2.5
o
2
I I
1.5 1
0.5 0 5
10
15
20
25
30
35
40
45
-0.5
50
55
TIME (WEEKS)
-1
-- 20"C (Concrete R) FIG 2 : Measured expansion on the concrete prisms (14x14x56cm).
+ 4-0"C 1007, HR O.gX Nc]20 Eq (Concrete A)
(- ! - : limit value of expansion I = 0.16 % after six months)
,--X--40"C 100~ HR 1.5,X l"la20 Ca "DOP NaOH"
(Concrete B)
8' 40"C 100,~ HR 1.Sg Na20 Eq "DOP KOH"
(Concrete C)
%" 6 m
5
~.1 [-.,
4
,.4
3
z a.l [.-,
2 1 o
|
I
2
4
I
I
I
6 8 10 TIME (MONTHS)
I
12
I
14
FIG 3 : Tensile strength on the concrete prisms (14x14x56cm).
478
L. Curtil and M.F. Habita
Vol. 24, No. 3
References
. . .
.
5. 6. 7. .
. 10. 11. 12. 13. 14. 15.
M.F. HABITA. "Contribution /i l'6tude de l'incidence de l'alcali-r6action sur le comportement m6carlique des poutres en b6ton arm6", Universit6 Claude Bernard, novembre 1992, 200 pages. M.F. HABITA, M. BROUXEL &~). PRIN. "Alkali-Aggregate Reaction Structural Effects : an experimental study", 9tu International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992,p403-410. L. CURTIL, J. GIELLY & M. MURAT. "the polarizing microscope: a tool of interest for investigation on concrete; application to carbonation", Cement and Concrete Research, vol 23, n°2, in press. J. Prlq~. "The role of petrography in the investigation of concrete and its constituents", Concrete 1987, vol 21, n°'/. Recommandations provisoires pour la pr6vention des d6sordres dus ~t l'alcalir6action - Laboratoire Central des Ponts et Chauss6es - Janvier 1991. Alkali-silica reaction jgeneral recommendations and guidance in the specification of building and civil engineering works - Irish Concrete Society - Dublin - 1991. D. BRAGG & K. FOSTER. "Relationship between petrography .and results of alkali-reactivity testing, samples from Newfoundland, Canada", 9tta International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p127-135. P.A. DAHL, I. MELAND & V. JENSEN. "N~rwegian experience with different test methods for Alkali-Aggregate Reactivity", 9 tu International Conference on AlkaliAggregate Reaction in Concrete, London, 1992, p224-230. R.G. SIBBICK & C;L. PAGE. "Susceotibility o f various UK Aggregates to AlkaliAggregate Reaction, 9m International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p980-987. G. WEST & R. SIBBICIC "Alkali-silica reaction in roads", Concrete, April 1988 and May 1989. B. LAGERBLAD & J. TRAGARDH. "Slowly reactir/g aggregates in Sweden mechanism and conditions for reactivity in concrete", 9 m International Conference on Alkali-Aggregate Reaction in Concrete, London, 1992, p570-578. I. SIMS, B. HUNT & B.F. MIGLIO. "Quantifying microscopical examinations of concrete for AAR and other durability aspects", Proceedings of the G.M. Idorn Durability Symposium, ACI Convention, Holm J. (Ed.), Toronto, 1990. K.T. ANDERSEN & N. THAULOW. 'q'he study of Alkali Silica Reactions in concrete by use of fluorescent thin sections", ASTM STP 1061 "Petrography applied to concrete and concrete aggregates", Erlin/Stark,, . editors, Philadelphia," USA. N. THAULOW, R.J. LEE & J. HOLM. An integrated optical SEM method for the identification of Alkali Silica Reaction in concrete sleepers", Proc. Int. symposium on precast concrete railway sleepers, 1991, Madrid, Spain. R.N. SWAMY & M.M. AL-ASALI. "Effect of alkali-silica reaction on the structural behavior of reinforced concrete beams", ACI Structural Journal, 1989, v.86, p451459.