Experimental Research On Durability Of Strain Hardening Cementitious Composite

SHCC (Strain Hardening Cementitious Composite) is a fiber reinforced cementitious composite which is in excess of 3% under uniaxial tensile loading and featured with strain-hardening and multiple cracking. The research on durability of SHCC is relatively little. So focusing on the researches of freezing-thawing resistance, carbonation resistance, permeability and resisitance to corrosion of steel of SHCC with 30%FA+40%SL, 50%FA and 65%FA+5%SF are investigated in this paper, compared with the norm cement mortar.After examined by accelerated freeze-thaw test, the norm mortar has been seriously damaged after 100 cycles in the water or 75 cycles in the salt solution. And after 150 cycles in the water, the mass loss, the changes of dynamic elasticity modulus and the changes of strength of SHCC just decrease little. The results show that the freezing-thawing resistance of the SHCC with 30%FA+40%SL is the best. And the damage caused by freezing and thawing in the salt solution is much serious than in the water. And the deflection of SHCC in four-point bending test has increased, and ultimate load has decreased as the numbers of freezing-thawing increase.Through the accelerated carbornation testing, the carbornation rate decreased, the strength and the carbornation depth appreciably increased as the carbornation time prolonged. Generally, carbornation resistance of SHCC is not better than the norm mortar, and among them the carbornation depth of SHCC with 65%FA+5%SF is the lowest. In the four-point bending test, the ultimate load and width of crack increased, the deflection decreased as the carbornation time added.The results of permeality tests showed that as the ages went the permeability of SHCC obviously decreased. And the permeability of SHCC with 65%FA+5%SF is the lowest of all. The permeability of SHCC is not better than norm mortar, and the addition of PVA fiber may result in the permeability increased.Accelerate reinforced corrosion test showed that the protection action of the steel of SHCC is much better than that of norm mortar. As the applied load increased the protection of the steel of SHCC degraded. The protection of the steel of SHCC with 65%FA+5%SF is the best of all. The steel keeps intact through 150 hour's voltage accelerated corrosion. But the protection of the steel of SHCC with 30%FA+40%SL when applied 40% of the limit load weakened quickly.