Quantitative Analysis On Packing Density And Pozzolanic Effect Of Ultra-high Performance Concrete

According to the compressible packing model and the method of specific strength, basing on the current research results,the paper improves the combined action of the packing effect and chemical effect of mineral particles to the influence on hardened properties of ultra-high performance concrete under different water-binder ratios and different proportion of mineral micro-power.Then the paper mainly carries on research of some relationships between the packing density and pozzolanic effect when compressible packing model is applied to fine powder mixture systems, and carries on the fitting among packing density and pozzolanic effect through the mathematical instrument.Finally,obtains the design method and procedure of concrete through a example which has important guiding significance to mix design that is preparing for ultra-high performancr concrete.The major research accomplishments were summarized as follows:(1)According to the characteristic that the packing density,which is calculated through the compressible packing model,may reflect the packing degree in order to establish the relations between the packing density and the pozzolanic effect.The packing density was handled dimensionlessly which was in order to define the contribution value of packing density and the contribution rate of packing density and proposed the corresponding formula.(2)When doped,under the different water-binder ratios,the variation law of packing density is similar with the value of compressive strength.The packing density and the pozzolanic effect with various constant of silica fume are close related under different water-binder ratios,the bigger contribution value of packing density is,the higher contribution rate of pozzolanic effect, and changing tendency of the packing density may approximately simulate the pozzolanic effect.(3)When co-doped,the packing effect of mineral particles has influence on the hardened properties of ultra-high performance concrete,the contribution rate of packing density and the contribution rate of pozzolanic effect under the different wanter-binder ratios are close related,and the changing tendency of the packing density may approximately simulate the variation of the contribution rate of pozzolanic effect.(4)Whether doped or co-doped,the relationship between the contribution rate of packing density and the contribution rate of pozzolanic effect can be established under different water-binder ratios,and the contribution rate of pozzolanic effect could be calculated through the contribution rate of packing density in 28d curing condition.(5)Under different water-binder ratios,through the relevance between the contribution rate of packing density and the contribution rate of pozzolanic effect with various content of mineral micro-power, establishes the model of mix design and primarily realizes computerizing, and the goal of guiding the mix design of ultra-high performance concrete is realized that using the compressible packing model and the method of specific strength.