水泥-淤泥焚烧灰复合胶凝材料的抗压强度与流动性

Compressive Strength and Fluidity of Cement-Sludge Incineration Ash Composite Cementitious Materials

摘要:

将湖、河淤泥焚烧后的残渣灰（淤泥焚烧灰，简称焚烧灰）在建材领域进行资源化处置，对比了焚烧灰与粉煤灰的火山灰活性，探讨了养护龄期、焚烧灰掺量和水胶比对水泥-焚烧灰复合胶凝材料净浆硬化浆体（简称为硬化浆体）抗压强度的影响；对比了焚烧灰与粉煤灰对新拌砂浆流动性的影响，探讨了焚烧灰掺量对砂浆流动性的影响规律；采用X射线衍射仪（XRD）和扫描电镜（SEM）研究了硬化浆体的微观结构.结果表明：焚烧灰的28 d抗压强度活性指数达到83%，可作为部分替代硅酸盐水泥的胶凝材料使用；随着焚烧灰掺量的增加，含焚烧灰新拌砂浆的流动性显著下降，硬化浆体的抗压强度早期下降明显，但后期有所提高；当焚烧灰掺量为20%时，硬化浆体的抗压强度达到最大值；水胶比越小，焚烧灰对硬化浆体抗压强度的影响越显著；焚烧灰的火山灰活性促进了复合胶凝材料后期的水化反应.

Abstract:

The residual ash from incinerating lake and river sludge was used as raw material in the field of building materials. The pozzolanic activities of sludge incineration ash （SIA） and fly ash （FA） were compared， and the effects of curing age， the addition of SIA and the water-binder ratio on the compressive strength of hardened cement-SIA composite cementitious materials paste （abbreviated as hardened cement paste）were investigated. The influences of SIA and FA on mortar fluidity were compared， and the influence of SIA addition on mortar fluidity was analyzed. The microstructure of hardened cement paste was analyzed by using X-ray diffraction analysis （XRD） and scanning electron microscopy （SEM）. The results show that the compressive strength activity index of SIA reaches 83% in 28 d， which can be used as a partial substitute for cement. With the increase of SIA addition， the fluidity of mortar containing SIA decreases significantly， and the compressive strength of hardened cement paste at early ages decreases sharply， while that at late ages increases to some extent. The compressive strength of hardened cement paste reaches the maximum value when the SIA addition is 20%. The smaller water-binder ratio is， the more significant the influence of SIA on the compressive strength of hardened cement paste is. The pozzolanic activity of SIA can promote the hydration of cement-SIA composite cementitious materials at later ages.