| 摘要: |
| 为了得到保证混凝土碳化耐久性前提下，在036~060范围内各水胶比（mW/mB）混凝土的临界粉煤灰掺量（wFA,c），在CO2体积分数（20±3）%，温度（20±2）℃，相对湿度（70±5）%的条件下进行加速碳化试验，测试了水胶比036，043，050，粉煤灰掺量（wFA）0%，20%，40%，60%以及水胶比060,粉煤灰掺量0%的混凝土碳化深度，混凝土试件经7d自然养护，自然养护期间日均气温为128℃.定量分析了水胶比与粉煤灰掺量对混凝土碳化性能的影响规律，建立了20mm碳化深度下混凝土临界粉煤灰掺量与水胶比之间关系的数学模型.结果表明:在各水胶比条件下，混凝土碳化深度均随粉煤灰掺量的增加而增大，当粉煤灰掺量超过20%以后，混凝土碳化速率均明显提高；混凝土碳化耐久性随水胶比增大而加速劣化.20mm碳化深度下混凝土临界粉煤灰掺量与水胶比之间关系的数学模型为:wFA,c=1748-2809mW/mB.根据该数学模型，在给定的水胶比条件下能计算出确保混凝土碳化耐久性的临界粉煤灰掺量. |
| 关键词: 混凝土 碳化 粉煤灰 水胶比 临界粉煤灰掺量 |
| DOI：103969/jissn1007 9629201501021 |
| 分类号: |
| 基金项目:河北省自然科学基金资助项目（E2011203218）;河北省建设科技研究计划项目（2011 151） |
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| Critical Use Level of Fly Ash Based on the Carbonation Durability of Concrete |
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ZHAO Qingxin, QI Lijian, PAN Huimin
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Key Laboratory of Mechanical Reliability for Heavy Equipments and Large Structuresof Hebei Province, Yanshan University, Qinhuangdao 066004, China
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| Abstract: |
| In order to obtain the critical use level（wFA,c） of fly ash for concrete of various water binder ratios（mW/mB） of 036060 under the promise of ensuring the carbonization durability of concrete, the carbonization depths of concretes with mW/mB of 036,043,050 and different use level（wFA） of fly ash of 0%, 20%, 40%, 60%，and with mW/mB of 060,use level of fly ash of 0% were tested, respectively. The accelerated carbonation tests were carried out under the condition of controlled CO2 volume fraction（20±3）%, temperature （20±2）℃ and relative humidity （70±5）%. Concrete specimens should be natural curing for 7d, in which the daily average temperature is 128℃. In addition, the effects of mW/mB and use level of fly ash on the carbonization of concrete were quantitative analyzed, and the mathematical model to describe the relationship between the critical use level of fly ash and mW/mB for 20mm carbonation depth was established. The experimental results show that the carbonation depth of concrete with different mW/mB increases with increasing the use level of fly ash. The use level of fly ash more than 20% has significant improvement on the carbonation rate. Moreover, the carbonization durability of concrete obviously decreases with increasing mW/mB. The mathematical model to describe the relationship between the critical use level of fly ash and mW/mB for 20mm carbonation depth is:wFA,c=1748-2809 mW/mB. Based on the mathematical model, the critical use level of fly ash which can ensure the carbonation durability of concrete can be calculated in a certain mW/mB. |
| Key words: concrete carbonation fly ash water binder ratio critical use level of fly ash |
