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| 水工混凝土的碱-硅反应抑制 |
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蔡跃波,丁建彤,白银
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南京水利科学研究院,江苏,南京,210029;水文水资源与水利工程科学国家重点实验室,江苏,南京,210029
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| 摘要: |
| 我国水利水电工程建设中越来越多地使用碱活性骨料,为了确保工程的安全性和兼顾经济性,需采取合理可靠的碱骨料反应抑制措施.提出用粉煤灰的比表面积与综合化学成分组合得到的物化因子作为评价粉煤灰品质的指标,以全面反映粉煤灰掺和料的化学、矿物、物理特性对抑制碱-硅反应效果的影响.水工混凝土对碱骨料反应已具备一定的自免疫力,这包括采用含碱活性石粉的人工砂时石粉起到的分散应力的作用,以及引气起到的消纳膨胀产物的作用.砂浆棒快速法高估了粉煤灰对水工混凝土碱-硅反应的抑制效果,混凝土棱柱体法由于配合比、骨料粒径均与实际水工混凝土差距较大,还无法真实反映抑制措施对水工混凝土碱-硅反应的抑制效果,需开发能够反映水工混凝土骨料粒径大、胶凝材料用量低、水胶比高等特点的碱-硅反应抑制效果评价试验方法. |
| 关键词: 水工混凝土 碱-硅反应 粉煤灰 自免疫力 试验方法 |
| DOI： |
| 分类号:TU528.04 |
| 基金项目:国家自然科学基金委员会、二滩水电开发有限责任公司雅砻江水电开发联合研究基金项目，水利部公益性行业科研专项经费项目 |
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| Inhibition of alkali-silica reaction of hydraulic concrete |
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CAI Yue-bo,DING Jian-tong,BAI Yin
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| Abstract: |
| The reactive aggregates are used more and more in water conservancy and hydropower engineering construction in China. For ensuring the safety and the economy of the projects, reasonable and reliable measures are needed to inhibit alkali-aggregate reaction. Derived from specific surface area and synthesized chemical composition, the Physical-Chemical Index of fly ash, which is the mostly used mineral admixtures to suppress ASR, is presented to evaluate the character of fly ash and is applied to integrally reflect the influence of the chemical, mineral and physical properties of fly ash on the suppressing effect of ASR. Hydraulic concrete already has some self-immunity to the ASR. On one hand, reactive stone powder contained in artificial sand disperses the concentrated stress of ASR, and on the other hand, air bubbles entrained by air-entraining agent can supply space to accommodate the products of ASR. The accelerated mortar bar test method overestimates the inhibition effect of fly ash on ASR. Because the mix proportion and the aggregate size of concrete prism are much different from practical hydraulic concrete, concrete prism test method also can not truly reflect the effect of suppressing measures. Considering the special characteristics of hydraulic concrete, such as bigger aggregate size, lower cementitious material content and higher W/C ratio, a new test method for evaluating the suppressing effect of ASR needs to be developed. |
| Key words: hydraulic concrete alkali-silica reaction fly ash self-immunity testing method |
