低钙粉煤灰粒度对水泥-粉煤灰复合胶凝材料力学性能与水化性能的影响  

Influence of Size Fraction of Low Calcium Fly Ash on Mechanical Performance and Hydration Properties of Cement-fly Ash Composite Gel Materials

作　　者：周祥[1] 李玉香[1] 郑召 马雪[1] 倪倩[1] 

机构地区：[1]四川省非金属复合与功能材料重点试验室-省部共建国家重点试验室培育基地西南科技大学,绵阳621010

出　　处：《混凝土与水泥制品》2017年第1期1-7,共7页China Concrete and Cement Products

基　　金：四川省教育厅项目(13ZA0159)

摘　　要：为了实现粉煤灰的高效利用,通过旋风分级机将原状粉煤灰分成D_(50)=5.06μm、15.63μm、35.01μm三个不同的粒度区间。不同粒度粉煤灰按照0、10%、20%和30%替代硅酸盐水泥。研究了粉煤灰粒度对水泥胶砂强度和水化性能的影响。结果表明,随着粉煤灰粒径的减小,粉煤灰水泥的各龄期强度都逐渐增加,掺入适量细粒度粉煤灰,水泥各龄期胶砂强度超过了硅酸盐水泥;粉煤灰水泥的水化放热速率和累积放热量都低于硅酸盐水泥,随着粉煤灰粒径的减小,粉煤灰水泥的水化放热速率和累积放热量增加。3d龄期时,粉煤灰水泥浆体Ca(OH)_2峰强度与硅酸盐水泥几乎相同;60d龄期时,随着粉煤灰颗粒粒径的减小,粉煤灰水泥浆体Ca(OH)_2峰的强度明显减小;SEMEDS分析表明,细粒度区间的粉煤灰水泥浆体比粗粒度区间的粉煤灰水泥浆体具有更致密的浆体结构且粉煤灰颗粒水化生成的是一种低Ca/Si的C-S-H凝胶。To achieve the high efficient utilization of fly ash, a low calcium original fly ash was classified into 3 fractions by an air classfier, with median particle size of 5.06μm, 15.63μm, 35.01μm,respectively. Three sizes of fly ash were used to partially replace Portaland cement at 0,10%, 20% and 30% by weight. The effect of size fraction on strength and hydration property of fly ash-cement complex eementitious materials incorporating fly ash was studied. Test resuhs indicated that with the decline in the size of fly ash, the strength of fly ash-cement mortars increased. And cement with appropriate content of fine fly ash showed higher strength than Portland cement at every age. The heat evolution results showed that the rate of heat evolution and cumulative heat of the fly ash cement were lower than Portland cement. With the de- cline in the size of fly ash, the rate of heat evolution and cumulative heat of the fly ash cement increased. The X-ray diffraction （XRD） results showed that the intensity peaks of Ca（OH）2 of fly ash cement were almost similar to Portland cement at 3 days. However, with the decline in the size of fly ash, the intensity peaks of Ca （OH）2 of fly ash cement decreased obviously at 60 days. The scanning electron microscope （SEM-EDS） results revealed that the hardened blended cement paste containing finer fly ash produced a denser structure and the surface of fly ash produced C-S-H gel with low Ca/Si molar during pozzolanic reaction.

关 键 词：低钙粉煤灰 粒度 粉煤灰水泥 水化性能 

分 类 号：TU528.041[建筑科学—建筑技术科学]