| The alkali-silica reaction is one of the most important factors leading to damage ofconcrete. ASR takes place slowly and is affected by many factors, so it is difficult topredict ASR and to repair the damaged structure caused by ASR. The effect of thesubstances containing aluminum on ASR has been studied and the mechanism has beendiscussed.According to ASTM C1293-08b, the concrete prism method was used to test theexpansion. The inhibiting effect of Al(OH)3and Al2O3on ASR in long term was studied,and the strength of concrete with Al(OH)3and Al2O3was tested. The results show thatAl(OH)3can suppress ASR expansion obviously, especially when mixing30%, however,Al2O3can not. The results also show that the addition of Al(OH)3and Al2O3isdisadvantages to the concrete strength.With the XRD analysis of samples in different ages, the influence of substancescontaining aluminum on the composition of the ASR products was studied by the methodof alkali solution immersion. The results show that the mineral composition of theproducts can be obviously changed by mixing Al(OH)3, and the aluminosilicate mineralssuch as Al2Si2O3(OH)4and CaAl2SiO8are found. The formation of the minerals consumesactive SiO2, so ASR is inhibited.The effect of substances containing aluminum on the morphology and compositionof the ASR products was studied by analyzing and comparing the SEM and the EDS ininterface between paste and glass in different ages. The results show that the morphologyand composition of the products in interface between paste and active aggregate can besignificantly altered by mixing30%Al(OH)3. On the one hand, Al3+has been introducedto C-S-H gels, leading it negatively charged. On the other hand, the aluminosilicatemineral with fiber mesh morphology is generated in interface between paste and glass bythe introduction of Al3+. The two kinds of effects will significantly reduce the amount ofharmful alkali in the concrete, and effectively inhibit the ASR. |
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