Research On Durability And Environmental Impact Assessment Of Domestic ECC As Pavement Materials

Lacking enough durability, cement concrete pavement is susceptible to damages, shortening service life. Engineered Cementitious Composite (ECC) has excellent mechanical properties and durability, so it can be used as a new kind of pavement material. But for now most PVA fibers in ECC materials are imported from Japan, which are expensive. Though domestic PVA fibers are economic, they differ from Japan PVA fibers technically so they cannot be simply substituted. Thus, research on a new kind of domestic ECC with moderate price, high mechanical properties and high durability has important economic and engineering values.Based on the current research on domestic ECC,this thesis investigates the compressive strength and bending performance of optimized domestic ECC material.Results show that the mechanical performance of domestic ECC can meet the operating requirement of pavement.The freezing-thawing resistance, chloride ion diffusion resistance and resistance to chemical solvent of domestic ECC were studied. Freezing-thawing tests show that, compared with ordinary concrete, domestic ECC has better frost resistance; as the experiment goes, the ductility of domestic ECC has an obvious downward trend, while bending strength experiences a decrease in the beginning and a bounce-back in the end; Pre-cracked domestic ECC specimen have a decreased bending strength and a slight variation of bending deformation after freezing-thawing experiment.Chloride ion diffusion tests show that the internal structure of domestic ECC is very compact, with a low diffusion coefficient. After precracking, however, the domestic ECC's resistance to chloride ion transport falls. Sulphate resistance tests show that sulfate has positive effect on flexural strength of pre-cracked and virgin domestic ECC specimen; the bending performance of domestic ECC can be drastically affected by acid,while alkali and sulphate increase the bending strength and decrease the bending deformation.Based on life cycle analysis (LCA), this article compares the environmental impact of domestic ECC and common concrete as pavement overlays. Results show that on the whole, the energy consumption and atmospheric pollution emission of domestic ECC are less than that of common concrete overlay.