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
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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 cementitious materials incorporating fly ash was studied. Test results 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 decline 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.
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 cementitious materials incorporating fly ash was studied. Test results 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 decline 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.
引文
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[2]黄莹,谢友均,刘宝举.粉煤灰掺量和细度对水泥凝结时间的影响[J].水泥,2003(12):4-6.
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[6]林震,陈益民,苏姣华,等.外掺磨细矿渣与粉煤灰的水泥基材料的亚微结构研究[J].硅酸盐学报,2000(z1):5-6.
[7]袁晓璐,周世华.胶凝材料细度匹配对粉煤灰-水泥砂浆干缩性能的影响[J].公路,2011(11):173-174.
[8]周立霞,王起才.颗粒细度与粉煤灰水泥胶砂性能的关系[J].建筑材料学报,2007,10(3):349-354.
[9]宋少民,刘振兴,范吉宝.粉煤灰细度和掺量对胶凝材料需水行为的影响[J].混凝土,2014(10):70-71.
[10]曹文聪.普通硅酸盐工艺学[M].武汉:武汉理工大学出版社,2013.
[11]Gopalan M K.Nucleation and pozzolanic factors in strength development of class fly ash concrete[J].Materials Journal,1993,90(2):117-121.
[12]沈旦申,张荫济.粉煤灰效应的探讨[J].硅酸盐学报,1981,9(3):60-63.
[13]Zhang T,Yu Q,Wei J,et al.A gap-graded particle size distribution for blended cements:analytical approach and experimental validation[J].Powder technology,2011,214(2):259-268.
[14]Chindaprasirt P,Jaturapitakkul C,Sinsiri T.Effect of fly ash fineness on microstructure of blended cement paste[J].Construction and Building Materials,2007,21(7):1534-1541.
[15]Marsh B K,Day R L.Pozzolanic and cementitious reactions of fly ash in blended cement pastes[J].Cement and Concrete Research,1988,18(2):301-310.
[16]Ahmaruzzaman M.A review on the utilization of fly ash[J].Progress in energy and combustion science,2010,36(3):327-363.
[2]黄莹,谢友均,刘宝举.粉煤灰掺量和细度对水泥凝结时间的影响[J].水泥,2003(12):4-6.
[3]周士琼,李益进,尹健,等.超细粉煤灰的性能研究[J].硅酸盐学报,2003,31(5):513-516.
[4]Feleko lu B,Türkel S,Kalyoncu H.Optimization of fineness to maximize the strength activity of high-calcium ground fly ashPortland cement composites[J].Construction and Building Materials,2009,23(5):2053-2061.
[5]周惠群,熊家国,吴红.粒度分布对复合水泥物理性能影响的研究[J].武汉理工大学学报,2007,29(8):48-49.
[6]林震,陈益民,苏姣华,等.外掺磨细矿渣与粉煤灰的水泥基材料的亚微结构研究[J].硅酸盐学报,2000(z1):5-6.
[7]袁晓璐,周世华.胶凝材料细度匹配对粉煤灰-水泥砂浆干缩性能的影响[J].公路,2011(11):173-174.
[8]周立霞,王起才.颗粒细度与粉煤灰水泥胶砂性能的关系[J].建筑材料学报,2007,10(3):349-354.
[9]宋少民,刘振兴,范吉宝.粉煤灰细度和掺量对胶凝材料需水行为的影响[J].混凝土,2014(10):70-71.
[10]曹文聪.普通硅酸盐工艺学[M].武汉:武汉理工大学出版社,2013.
[11]Gopalan M K.Nucleation and pozzolanic factors in strength development of class fly ash concrete[J].Materials Journal,1993,90(2):117-121.
[12]沈旦申,张荫济.粉煤灰效应的探讨[J].硅酸盐学报,1981,9(3):60-63.
[13]Zhang T,Yu Q,Wei J,et al.A gap-graded particle size distribution for blended cements:analytical approach and experimental validation[J].Powder technology,2011,214(2):259-268.
[14]Chindaprasirt P,Jaturapitakkul C,Sinsiri T.Effect of fly ash fineness on microstructure of blended cement paste[J].Construction and Building Materials,2007,21(7):1534-1541.
[15]Marsh B K,Day R L.Pozzolanic and cementitious reactions of fly ash in blended cement pastes[J].Cement and Concrete Research,1988,18(2):301-310.
[16]Ahmaruzzaman M.A review on the utilization of fly ash[J].Progress in energy and combustion science,2010,36(3):327-363.
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