We adopted a notch method to study the influence of crack width(macro level) on chloride transport and binding of cracked concrete under a non-steady state migration test.The results show that migration coefficient of cracked concrete increases with increasing crack width up to a critical value(0.43 mm),for the whole concrete or the area close to crack;the increase of migration coefficient could be independent from crack parameter when a critical crack width is reached.For chloride binding,Langmuir isotherms of cracked concrete samples exhibit the similar decreasing trend as crack width increases from 0.27 to 1.96 mm.The increased current value could be responsible for the trend based on the hypothesis of electric force.
The influences of silica fume and aluminum sulfate on hydration process of sulfoaluminate cement were carried out by ring flow,setting time,hydration heat,XRD and DTG analyses.In addition,mortar mixtures with different functional additives have been studied through compressive strength,flexural strength,volume stability at early age and porosity characterization tests.The results show that the addition of silica fume and aluminum sulfate reduces the fluidity and shortens the setting time of sulfoaluminate cement paste,promoting hydration process and increasing hydration products at early age.In the case of appropriate proportion of mortar,the inclusion of hydroxy propyl methyl cellulose,dispersible polypropylene fiber and organic silicon kind of defoamer can control segregation and bleeding,improve mechanical strength and volume stability at early age,and modify the pore distribution of sulfoaluminate cement mortar,respectively.The sulfoaluminate cement mortar can carry out gravitational grouting in the absence of outside force,the compressive strength of 2 hours and 24 hours have reached 26 and 58 MPa respectively,and have good microexpansion and tiny pore distribution characterization.
