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Research Progress and Performance Evaluation of Polyvinyl Alcohol Fiber Engineered Cementitious Composites
Polyvinyl alcohol fiber engineered cementitious composites (PVA-ECC) have attracted wide attention due to their high toughness and narrow cracks. This review evaluated research results on PVA-ECC to further promote its research and application. The suitable length, diameter, and content of PVA fiber for ECC were recommended. The surface modification method of PVA fiber was determined and the dispersion evaluation method of PVA fiber was explored. An investigation into the mechanical properties of PVA-ECC was conducted, and the influence of PVA fiber content and fly ash content was evaluated. The improvement degree of PVA fiber on the durability of ECC and the strengthening mechanism was clarified. Results indicate that the recommended PVA fiber length for ECC was 12 mm, the diameter was 39 μm or 40 μm, and the content was 0.60–2.00%. The surface physical modification method was recommended for PVA fiber surface modification, and the mass equalization method was recommended for the evaluation of PVA fiber dispersion. With ordinary concrete, the tensile strain of PVA-ECC can be increased by 200–320 times, and the average improvement degree of flexural strength was 43%. Tensile strength and flexural strength of PVA-ECC increase first and then decrease with the increase in fiber content. With the increase in fly ash content, the tensile strength, compressive strength, and flexural strength of PVA-ECC decreased. PVA fiber content, fly ash content, and freeze–thaw medium are the main factors affecting the frost resistance of PVA-ECC. Compared with ordinary concrete, the average decreased degree of electric flux of PVA-ECC at 28 d was 21%, and the average decreased degree of carbonation depth of PVA-ECC at 3–28 d was 9–20%.
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