羧丙基甲基纤维素对原位化学发泡轻集料混凝土性能的影响

Influence of HPMC on the Properties of Lightweight Aggregate Concrete by Chemical Foaming in situ

以污泥烧胀陶粒为轻集料、羧丙基甲基纤维素(HPMC)为稳泡剂、H_2O_2溶液为化学发泡剂、膨胀珍珠岩为发泡剂载体制备原位发泡轻集料混凝土.结果表明,HPMC掺量为0.05%~0.125%(ω)时具有较好的稳泡和抗离析双重作用,试样密度随HPMC量增加而轻微增大,养护28 d的试样抗压、抗折强度和导热系数均随HPMC量增加而增大,48 h的吸水率随其量增加而降低;HPMC掺量为0.125%~0.15%(ω)时,试样性能随其量增加出现相反的变化规律.HPMC掺量为0.125%(ω)时,试样密度为1 245 kg/m^3,养护28 d的试样抗压强度为31 MPa,抗折强度为6 MPa,48 h的吸水率为6.1%,导热系数为0.33 W/(m?K).

The lightweight aggregate concrete（LAC） specimens were prepared by chemical foaming in situ, the sludge expanded ceramsite, hydroxy propyl methyl cellulose（HPMC）, H2O2, and expanded perlite were used as the aggregate, foam stabilizer, chemical foaming agent（CFA）, and carrier for CFA, respectively. The results showed that HPMC content in the range of 0.05%-0.125%（ω） had the promising performance of foam stabilization and anti-segregation for the preparation of LAC. Accompanying to the slight increase of bulk density of resulting LAC specimens, the 28 d curing compressive strength, the flexural strength and the thermal conducting coefficient were increased, whereas the 48 h water absorption was decreased with the increase of HPMC content. For HPMC in the range of 0.125%-0.15%（ω）, the properties of resulting LAC specimens were changed with the variation of HPMC content conversely as compared with that in the range of 0.05%-0.125%（ω）, the slump of fresh LAC specimens was decreased slightly. For the resulting LAC specimen with HPMC content of 0.125%（ω）, the bulk density was 1 245 kg/m^3, the 28 d curing compressive strength was 31 MPa, the 28 d curing flexural strength was 6 MPa, the 48 h water absorption was 6.1%, and thermal conducting coefficient was 0.33 W/（m·K）, respectively.