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1、2017年第1期混凝土与水泥制品2017No.11月CHINACONCRETEANDCEMENTPRODUCTSJanuary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周祥,李玉香,郑召,马雪,倪倩(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)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D50=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
2、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;SEM-EDS分析表明,细粒度区间的粉煤灰水泥浆体比粗粒度
3、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。关键词:低钙粉煤灰;粒度;粉煤灰水泥;水化性能Abstract:Toachievethehighefficientutilizationofflyash,alowcalciumoriginalflyashwasclassifiedinto3frac-tionsbyanairclassfier,withmedianparticlesizeof5.06μm,15.63μm,35.01μm,respectively
4、.ThreesizesofflyashwereusedtopartiallyreplacePortalandcementat0,10%,20%and30%byweight.Theeffectofsizefractiononstrengthandhydrationpropertyofflyash-cementcomplexcementitiousmaterialsincorporatingflyashwasstudied.Testresultsindicat-edthatwiththedeclineinth
5、esizeofflyash,thestrengthofflyash-cementmortarsincreased.Andcementwithappropri-atecontentoffineflyashshowedhigherstrengththanPortlandcementateveryage.TheheatevolutionresultsshowedthattherateofheatevolutionandcumulativeheatoftheflyashcementwerelowerthanPor
6、tlandcement.Withthede-clineinthesizeofflyash,therateofheatevolutionandcumulativeheatoftheflyashcementincreased.TheX-raydiffraction(XRD)resultsshowedthattheintensitypeaksofCa(OH)2offlyashcementwerealmostsimilartoPortlandce-mentat3days.However,withthedeclin
7、einthesizeofflyash,theintensitypeaksofCa(OH)2offlyashcementde-creasedobviouslyat60days.Thescanningelectronmicroscope(SEM-EDS)resultsrevealedthatthehardenedblendedcementpastecontainingfinerflyashproducedadenserstructureandthesurfaceofflyashproducedC-S-Hgel
8、withlowCa/Simolarduringpozzolanicreaction.Keywords:Lowcalciumflyash;Sizefraction;Flyashcement;Hydrationproperties中图分类号:TU528.041文献标识码:A文章编号:1000-4637(2017)01-01-07[1-6]0前言长等缺陷,限制了粉煤灰的应用。许多研究报道,粉煤灰作为一种固体废弃物,因其具有潜在的粉煤