摘要
为了研究混凝土中粗细骨料搭配比例对碱活性粗骨料碱-硅酸反应(ASR)的影响,根据工程中混凝土常见的粗细骨料比例设计了四种混合骨料比例,使用与粗骨料同源的细骨料替代粗骨料,采用砂浆棒快速法(AMBT)对四种不同比例混合骨料的碱活性进行评价;探究单掺25%粉煤灰、复掺25%粉煤灰和5%硅灰对混合骨料碱-硅酸反应的抑制效果,并对反应产物进行XRD分析。结果表明:四种不同比例的混合骨料仍具有潜在碱活性且不存在明显的“最劣比”现象;砂浆棒试件中掺加粉煤灰与硅灰后,碱活性骨料比例较低的混合骨料所受到的ASR膨胀抑制效果更明显;粉煤灰与硅灰主要通过减少水泥水化产物中的CH,增加C-S-H以及改性C-S-H以增强其结合碱离子的能力来减弱ASR。
In order to study the effect of coarse and fine aggregate matching ratios in concrete on the alkali-active coarse aggregate alkali-silicate reaction(ASR),four kinds of mixed aggregate ratios are designed according to the common coarse and fine aggregate ratios in engineering,and the alkali activity of the four kinds of mixed aggregates with different ratios was evaluated by Accelerated Mortar Bar Test(AMBT).The inhibition effects of 25% fly ash alone,25% fly ash and 5% silica fume on the ASR of mixed aggregates are investigated,and the reaction products of the specimens are analyzed by XRD.The results show that the four different ratios of mixed aggregates still have alkali reactivity,and there is no obvious"pessimum"phenomenon.The inhibition of ASR expansion is more pronounced for mixed aggregates with lower proportions of alkali-active aggregates after the addition of fly ash and fly ash with silica fume in mortar bar specimens.Fly ash and silica fume inhibit ASR mainly by reducing CH,increasing C-S-H and modifying C-S-H to enhance its ability to bind alkali ions in cement hydration products.
作者
祁义卿
钱文勋
白银
张丰
葛龙甄
QI Yiqing;QIAN Wenxun;BAI Yin;ZHANG Feng;GE Longzhen(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Nanjing Hydraulic Research Institute,Nanjing 210029,China)
出处
《粉煤灰综合利用》
CAS
2024年第2期1-5,16,共6页
Fly Ash Comprehensive Utilization
基金
国家重点研发计划(2020YFC1511902)。
关键词
碱-硅反应
碱活性抑制
砂浆棒快速法
粉煤灰
硅灰
alkali-silica reaction
alkali-reactivity inhibition
accelerated mortar bar test
fly ash
silica fume
