基于最紧密堆积理论配制超高强混凝土的试验研究

Experimental study on preparation of ultra high strength concrete by the theory of the most compact

研究了超细粉煤灰单掺、硅灰一超细粉煤灰复掺对复合水泥粉体压实体空隙率、硬化浆体孔结构和抗压强度的影响规律；同时，研究了砂率对砂石骨料混合体系空隙率的影响规律；并结合两者研究内容开展超高强混凝土配制研究。结果表明：超细粉煤灰30％时，超细粉煤灰一水泥复合粉体压实体空隙率最小；硅灰在0-10％范围内等质量取代超细粉煤灰，可进一步降低硅灰-超细粉煤灰—水泥复合粉体压实体空隙率，硅灰掺量8％时，复合水泥压实体空隙率最低；复合水泥粉体压实体空隙率越小，复合水泥硬化浆体孔隙率越小、有害孔含量越少、28、60d抗压强度越高；砂率45％时，砂石骨料混合体系空隙率最低；通过调整胶凝材料粉体堆积空隙率和砂石骨料混合空隙率，可配制出28d抗压强度≥135MPa，60d抗压强度可达到≥145MPa的超高强自密实混凝土。

The effects of UFA single doped and silica fume-UFA co-doped on composite cement powder pressure entities porosity, hard- ened paste pore structure, hardened paste compressive strength are studied.The study of the influence of sand ratio on the voidage of aggre- gate.Experimental study on preparation of ultra high strength concrete according to the two research.The results showed that when the con- tent of ultra fine fly ash was 30% ,UFA-Cement composite achieved the densest packing density.In the range of 0-10%, silica fume equal replace UFA can continue to reduce the pressure entities porosity of Silica fume-UFA-cement composite powder, when the content of silica flame was 8%, silica fume-UFA-cement composite achieved the densest packing density.When the compacting voidage value reaches mini- mum, the average pore radius and maximum pore radius of hardened cement paste reach the minimum values.In addition,the 28 d and 60 d compressive strength of composite cement paste was higher.when the sand ratio was 45%, aggregate achieved the densest packing density. Adjust the compacting voidage of composite cement and the voidage of aggregate, can produce ultra high strength self-compacting con- crete with 28 d compressive strength 〉I 135 MPa, 60 d compressive strength ≥ 145 MPa.