Influence Of Constituent Materials On The Resistance Of Concrete To Chloride Ion Penetration

The durability of cement paste, mortar and concrete with different constituent materials was studied in this thesis, and the focus is on inspecting the resistance to chloride ion penetration. The cement paste part inspects the influence on resistance to chloride ion penetration by different added materials and different ages when the total replaced amount of mineral admixture is 50%; The mortar part inspects the influence on resistance to chloride ion penetration by different water-binder ratios, different added materials, different sand-binder ratios and different ages; The concrete part inspects the influence on resistance to chloride ion penetration and compressive strength by different water-binder ratios, different added materials, different sand percentage and different ages. Electrical conductance of cement paste, mortar and concrete at different ages is tested by ASTM C1202.The results of the experiments indicate: (1) Cement paste with slag and expansion agent can greatly improve its resistance to chloride ion penetration, but the effect of using fiber is not obvious. (2) The resistance to chloride ion penetration of mortar with different added materials performs differently; the resistance with emulsion powder is better than that with slag, than that with expansion agent and than that with fiber, and the resistance with emulsion powder, slag and expansion agent is the best. When the sand-binder ratio is 3 or 4, the resistance to chloride ion penetration is the best, that is better than that when the sand-binder ratio is 1 or 2. (3) When the added material is slag, the strength of concrete decreases at early ages but increases at 28-days and 56-days; however, the resistance to chloride ion penetration is improved greatly. (4) When slag and expansion agent are used together, the resistance to chloride ion penetration is improved obviously. (5) When the sand percentage is between 40% and 45%, the compressive strength of the concrete is greatest and the resistance to chloride ion penetration is the excellent. (6) In the process of testing the resistance to chloride ion penetration, if the electric current is quite stable throughout, the final quantity of electricity is linearly dependent on the initial electric current; therefore, initial current can instead quantity of electricity and becomes referenced index to evaluate concrete's resistance to chloride ion penetration under certain conditions, but the application scope has not been decided. (7) The cement paste content in, the concrete is the important factor which affects the resistance to chloride ion penetration.