外加剂对泡沫混凝土孔结构及强度的影响

关键字：外加剂,泡沫混凝土,孔结构

（1.四川大学 建筑与环境学院，四川 成都  610064；2.四川建筑职业技术学院，四川 德阳  618000；
3.成都大学 建筑与土木工程学院，四川 成都  610106）

    摘要：以P·O42.5R水泥、植物蛋白发泡剂、电厂粉煤灰为原料，辅以聚羧酸减水剂、速凝剂、促凝剂，采用物理发泡法制备干密度为500 kg/m3的泡沫混凝土。使用流变仪、SEM、XRD对试样净浆性能、气孔结构及其分布进行表征，并研究外加剂对净浆的相对粘度和硬化泡沫混凝土的孔结构及强度的影响。结果表明：在配方中分别掺入0.2%速凝剂、0.3%促凝剂可使试样50~400 μm的气孔比例分别达到93.67%和94.67%，气孔平均直径分别为182.90、149.86 μm，28 d抗压强度分别达到3.20 MPa、3.31 MPa。掺减水剂（缓凝型）使泡沫混凝土气孔平均直径减小，但同时也增加开口孔隙率，掺入0.1%的减水剂样品的28 d抗压强度为2.88 MPa。
    关键词：泡沫混凝土；相对粘度；气孔结构；抗压强度
    中图分类号：TU528.2        文献标识码:A        文章编号：1001-702X（2017）10-0092-05

Effects of admixture on air-void structure and strength of lightweight foamed concrete
HU Chi1，2，LI Hui2，LIU Zhongwei2，WANG Qingyuan1，3
（1.College of Architecture & Environment，Sichuan University，Chengdu 610064，China；
2.Sichuan College of Architectural Technology，Deyang 618000，China；
3.School of Architecture and Civil Engineering，Chengdu University，Chengdu 610106，China）

    Abstract：The lightweight foamed concrete（500 kg/m3） was prepared by physical foaming using ordinary Portland cement（42.5R），vegetable protein foaming agent and fly ash as raw materials accompanied by polycarboxylate superplasticizer，accelerator and coagulation accelerator. The performance of cement paste，air-void structure and distribution were characterized by rheometer，SEM，XRD，the effect of admixture on relative viscosity of cement paste, air-void structure and strength of samples was also discussed. The results show that by mixed 0.2% of accelerator，0.3% of coagulant in the production of foamed concrete formulations can make the porosity ratio of samples 50~400 μm pore respectively reached 93.67% and 94.67%，an average pore diameter were 182.90 μm，149.86 μm，28 d compressive strength reached 3.20 MPa，3.31 MPa. Polycarboxylate superplasticizer（retardation type） shrank the average pore diameter of the foamed concrete，but also increased the open porosity，the compressive strength at 28 d was 2.88 MPa when mixed 0.1% water reducer.
    Key words：foamed concrete，relative viscosity，air-void structure，compressive strength