矿物掺合料对超轻泡沫混凝土气孔结构及性能的影响
Effects of Mineral Admixture on Air-void Structure and Performance of Ultra-lightweight Foamed Concrete
关键词：
超轻泡沫混凝土；矿物掺合料；气孔结构；抗压强度；导热系数
Key words：
Ultra-lightweight foamed concrete; Mineral admixture; Air-void structure; Compressive strength; Thermal conductivity
刊期：
２０19年第6期
DOI：
10.19761/j.1000-4637.2019.06.059.05
文章编号：
基金项目：
国家重点研发计划项目（2016YFC0701004）；四川省科技计划项目（2018GZ0152、18YYJC0904）；西南科技大学研究生出国（境）交流专项基金项目
作者：
蒋 俊，李 军，牛云辉，卢忠远，晏云华，蔡 攀
单位：
1.西南科技大学环境友好能源材料国家重点实验室，绵阳 621010；2.西南科技大学材料科学与 工程学院，绵阳 621010；3.四川峨胜水泥集团股份有限公司，乐山 614000
摘要
摘 要：采用物理发泡工艺制备了孔隙率大于90%的超轻泡沫混凝土，结合Image-pro plus、热分析及扫描电镜等手段对硬化超轻泡沫混凝土气孔结构及微观结构进行了表征，同时研究并对比了粉煤灰与矿粉对泡沫混凝土硬化性能的影响。研究表明：粉煤灰与矿粉取代水泥增大了试样气孔孔径，但对导热系数影响不明显；矿粉可改善试样抗压强度，当矿粉取代20%的水泥时，试样干密度为165.2 kg/m3，孔隙率为93.0%，56 d抗压强度可提升至0.47 MPa。
Abstract: Ultra-lightweight foamed concrete with a porosity greater than 90% was prepared by pre-foaming method.The air-void structure and microstructure of hardened samples were characterized by Image-pro plus, SEM and TG, and the effect of fly ash and granulated blast furnace slag on hardened properties of foamed concrete was studied and compared. The results indicate that the replacement of cement with fly ash or granulated blast furnace slag increases air-void size, but has slight effect on the thermal conductivity of foamed concrete. Granulated blast furnace slag can be used to improve compressive strength of sample. When the slag replaces 20% cement, the dry density of the sample is 165.2 kg/m3,the porosity is 93.0%, and the 56 d compressive strength of the foamed concrete can increase to 0.47 MPa.
结论
（1）当粉煤灰、矿粉取代水泥量增加时，超轻泡沫混凝土基体用水泥净浆塑性黏度及极限剪切应力减小，粉煤灰在改善该净浆的流变性能方面强于矿粉。
（2）粉煤灰矿粉取代水泥量从0增加至25%，超轻泡沫混凝土气孔孔径变大，气孔孔径分布范围扩大，矿粉使硬化试样D50增加75.9%，粉煤灰使试样D50增加41.3%。
（3）因粉煤灰取代水泥使得气孔孔径变大，孔间壁密实程度未见改善，硬化试样抗压强度下降，而矿粉取代水泥改善孔间壁密实程度，提升了硬化试样的抗压强度，当矿粉取代20%的水泥时，干密度为165.2 kg/m3，孔隙率为93.0%，56 d抗压强度为0.47 MPa。
（4）矿物掺合料对硬化试样导热系数影响较小，当矿粉与粉煤灰取代水泥量为0~25%时，导热系数在0.050~0.056 W/（m·K）之间变化，当矿粉取代20%水泥时，试样导热系数为0.054 W/（m·K）。
参考文献
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引用本文
蒋俊,李军,牛云辉,等.矿物掺合料对超轻泡沫混凝土气孔结构及性能的影响[J].混凝土与水泥制品,2019(6):59-63.
JIANG J,LI J,NIU Y H,et al.Effects of Mineral Admixture on Air-void Structure and Performance of Ultra-lightweight Foamed Concrete[J].China Concrete and Cement Products,2019(6):59-63.
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