Key words: concrete alkali-silica reaction, nuclear radiation, amorphization, quartz, plagioclase, nuclear power plant 85 (2008) 11

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1 The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the e#ect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the e#ect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca 2 ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca 2 ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The e#ect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 10 8 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. Key words: concrete alkali-silica reaction, nuclear radiation, amorphization, quartz, plagioclase, nuclear power plant M M M M M 85 (2008) 11

M [Ca 2 ][OH ] 2 OH Ca 2 Ca 2 2 OH Si O 3 M 1) 1) 2) 3) 2 4) 5), 6) 2. 2.1 60 CaO, 20 SiO 2, 8 Al 2 O 3, 3 Fe 2 O 3, 3 CaSO 4, Na 2 O 0.

2 M [Ca 2 ][OH ] 2 OH Ca 2 Ca 2 2 OH Si O 3 M 1) 1) 2) 3) 2 4) 5), 6) CaO, 20 SiO 2, 8 Al 2 O 3, 3 Fe 2 O 3, 3 CaSO 4, Na 2 O ASR 2 ASR 2 (SiO 2 ) ASR ASR 1 2 3

3 7) ASR Na 2 O 0.6 Na 2 O 3kg/m 3 ASR ASR ASR 0.6 ASR ASR NHK ASR ASR NaCl NaOH ASR FRP PC 2.2 ASR ASR 3 ASR ASR 3 3 ASR 85 (2008) 13

4 5 ASR Ca 2 [Ca 2 ] [Ca 2 ] [OH ] 2 ASR ASR 14 4 ASR Ca Si O Si 2OH 2 mh 2O 2 Si O (H 2O) m Ca(OH) 2 2 Si O (H 2 O) m Ca(OH) 2 Si O Ca O Si 2 mh 2 O 5 V P G (G (P V k k 1 V (V (P 1/k P 0 V 0 2 DG (P P 0 )V 0 P max P max P 0 DG V 0 87 kj/mol 400 MPa 2

5 ASR 2.3 ASR M ASR cm cm cm EPMA X 6 ASR 3 4 S ASR Si (Andesite) 4 M M NaOH Ca(OH) 2 NaOH Ca (OH) mm 5 1, 2, 3 1 a) NaOH b) )c Ca(OH) 2 NaOH Ca(OH) 2 NaOH NaOH 5 5 Ca(OH) d) 2, a) NaOH Ca(OH) 2 Ca(OH) a) NaOH 3 1 0/5 0/5 0/5 0/5 0/5 3/5 a) 80 b) 0.1 mol/dm 3 c) d) NaOH Ca(OH) 2 10 : 1 85 (2008) 15

6 7 5mm ASR ASR ASR ASR ) Gy g 9) 14) n/cm ), 10) 15), 16) n/cm ASR 3.2 ASR g 200 kev Ar 30 kev a- ASR 8 NaOH

8 ASR 200 kev Ar 450 nm 4 9 10 15 /cm 2 Ar b g 10 12 Gy ( 0.1 MeV) 1 10 20 n/cm 2 17) 22) 700 1/10 3 ASR ASR (NaAlSi 3 O 8 ) 0.

7 8 ASR 200 kev Ar 450 nm /cm 2 Ar b g Gy ( 0.1 MeV) n/cm 2 17) 22) 700 1/10 3 ASR ASR (NaAlSi 3 O 8 ) 0.11 (CaAl 2 Si 2 O 8 )(KAlSi 3 O 8 ) kev kev Ar 1 mol/dm 3 NaOH kev 1 mol / dm 3 NaOH Gy 35 ASR n/cm 2 b g Gy n/cm 2 85 (2008) 17

8 2 b, g b, g Gy 50, n/cm Gy 5, n/cm Gy n/cm ASR 4. ASR ASR ASR ASR b g ASR ASR 18 ASR ASR ASR ASR ASR ASR 1) S. Morinaga, Preprint of the East Asia Alkali- Aggregate Reaction Seminar, Tottori, Japan, 1997, p. 101 (in Japanese). 2) M. Miura and T. Ichikawa, Kensetsuyou Genzairyou, 6, 43(1996) (in Japanese). 3) M. Miura and T. Ichikawa, Concrete Research and Technology, 8, 135 (1997) (in Japanese). 4) T. Ichikawa and M. Miura, Cement and Concrete Research, 37, 1291 (2007). 5) T. Ichikawa and H. Koizumi, J. Nucl. Sci. Technol., 39, 880 (2002). 6) T. Ichikawa and T. Kimura, J. Nucl. Sci. Technol., 44, 1(2007). 7) B. Fournier and M.-A. Bér ubé, Can. J. Civ. Eng., 27, 167 (2000). 8) H. K. Hilsdorf, J. Kropp, and J. H. Koch, ACI SP-55, 223 (1977).

9 9) B. T. Kelly and I. Davisson, 2nd Conference on Prestressed Concrete Pressure Vessels and Their Insulation, London, 1969, p ) L. F. Elluch, F. Dubois, and J. Rappeneau, ACI SP-34, 1071 (1972). 11) D. C. McDowall, Proceedings of an Information Exchange Meeting on Results of Concrete Radiation Programms, Brussel, 1971, p ) H. Nakamura, M. Sagino, K. Yamada, N. Yamada, Y. Murase, and M. Fukushima, Cement Science and Concrete Technology, 37, 256 (1983) (in Japanese). 13) K. Yamada, Y. Murase, and N. Yokota, Cement Science and Concrete Technology, 37, 337 (1983) (in Japanese). 14) M. Kakizaki, Y. Idei, T. Sukegawa, Y. Akutsu, H. Hatano, and H. Kurioka, J. Struct. Constr. Eng. AIJ, 488, 1(1996) (in Japanese). 15) V. B. Dubrovskij, Sh. Sh Ibragimov, A. Ya. Ladygin, and B. K. Pergamenshckik, Atomnaya Energiya, 21, 108 (1966). 16) A. Pederson, Proceedings of an Information Exchange Meeting on Results of Concrete Radiation Programms, Brussel, April 1971, p. 5 (1971). 17) G. Laermans, in Structure and Bonding in Noncrysatalline Solids, ed. by G. E. Walrafen and A. G. Revesz, (Plenum, New York, London, 1986), p ) L. Douillard and J. P. Dyraud, Nucl. Instr. Meth. B, 107, 212 (1996). 19) F. Harbsmeier and W. Bolse, J. Appl. Phys., 83, 4049 (1998). 20) W. L. Gong, L. M. Wang, and R. C. Ewing, J. Appl. Phys., 84, 4204 (1998). 21) S. Dhar, W. Bolse, and K-P. Lieb, J. Appl. Phys., 85, 3210 (1999). 22) S. Dhar, S. W. Bolse, and K-P. Lieb, Nucl. Instr. Meth. B, 148, 683 (1999). 85 (2008) 19

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