Title: Scaling Resistance of Ordinary and Very Early Strength Concrete Reinforced with Polypropylene Fibers
Author(s): K.-K. Yun, J.-H. Lee, C.-W. Hong, and J.-S. Park
Publication: Symposium Paper
Appears on pages(s): 243-258
Keywords: concrete; early strength; fiber-reinforced concrete
This study focused on the investigation of durability characteristics of very early strength concretes incorporating polypropylene fibers and application feasibility of these into the highway pavements. A series of laboratory tests were performed to assess the strength development and scaling resistance. The test of surface scaling resistance was performed according to ASTM C 672 exposed to frost in the presence of de-icing chemicals. The experimental variables included cement types, fiber contents and concrete mixtures. The compressive strength of very early strength concrete at 3 hours was measured as 22 MPa, which corresponded to the strength at 7 days or 28 days of ordinary portland cement concrete. This may enable the repaired concrete pavement to be opened to traffic 3 hours after concrete placement. There was little effect of polypropylene fiber reinforcement on compressive strength. The fiber reinforced concretes exhibited noticeably higher flexural strength than the reference concrete at all ages. The plain concrete slabs were given a visual rating of 3 or 4, and according to ASTM Standard C 672. This corresponds to moderate to severe scaling. The fibrous concrete performed better than the plain concrete slab which was given a visual rating of 0 or 1. This corresponds to no scaling or very light scaling. As the amount of fiber reinforcement increased the surface scaling resistance increased. The scaling resistance of very early strength concrete was comparable to that of ordinary concrete from the visual rating. Thus, the developed very early strength concrete may be satisfactory for use in repair works for pavements.