Study On Micro Structure And Properties Of High Performance Marine Concrete

High performance marine concrete is a kind of porous cement-based building materials.For its components,in addition to the coarse and fine aggregate,the hardened cement paste plays an important role in the mechanical strength and durability,which is used for splicing coarse and fine aggregate.The degree of compactness,pore connectivity,ore composition and other factors determine the durability of concrete,and the selection of cementitious materials directly determines the physical and chemical properties of hardened cement paste,which laid the foundation for the normal use of concrete.Therefore,analysing the relationship between combining macroscopic properties and microstructure of concrete binder pastes has very important significance in understanding properties of high performance marine concrete parameters and rules.In this paper,6 mix proportions of high performance marine concrete and cementitious materials are proposed.The mix proportion contains three mineral admixtures,cement,slag and fly ash are included,With pure cement as control group.Utilizing X ray diffraction,SEM scanning electron microscopy and MIP to study the microstructure of hardened cement paste which cured 3 days and 28 days.Selecting the structure of the hardened cement paste pore,hydration process,concrete/cement mortar compressive strength and concrete electric flux as the research object to analyze The relationship between microstructure and macroscopic properties systematically.This paper summarizes the formation of mineral admixtures on the microstructure of hardened cementitious materials and the effects of different proportions on the hydration process.Pointed out that the hardened cementitious paste porosity,pore size distribution changes of relationship between the compressive strength of concrete and electric flux,the concept of the median aperture is used to compare the above relations for the first time.Finally found the amount of mineral admixture and cement used in the optimum pore size distribution.The results of this study are clear in theory.It is mainly about practical engineering application,which has a very important guiding significance for the design and preparation of marine concrete.