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Internal Curing by Porous Calcined Bauxite Aggregate in Ultrahigh-Performance Concrete
Ultra-high performance concrete (UHPC) has more severe autogenous shrinkage than ordinary concrete, which may lead to increased cracking risks. Thus, a suitable and effective agent for internal curing (IC) of UHPC without a negative effect on the strength is needed to solve this problem. A type of strong and porous aggregate made of calcined bauxite was used in this study to achieve low shrinkage and lower-cement UHPC based on the modified Andreasen and Andersen model, and together, a reference mixture made of basalt aggregate was prepared. The autogenous shrinkage of UHPC with basalt aggregate reached at the age of 28 days, while the autogenous shrinkage of the UHPC with calcined bauxite was substantially reduced or a slight expansion occurred. This was found to be due to the internal curing effect provided by the calcined bauxite aggregate. A pronounced 56-day compressive strength of 148 MPa was achieved for this standard-cured UHPC without steel fibers. The low shrinkage UHPC internally cured by calcined bauxite aggregate can be applied to on-site cast UHPC structures or bridge decks that are prone to shrinkage cracking.
Internal Curing by Porous Calcined Bauxite Aggregate in Ultrahigh-Performance Concrete
Ultra-high performance concrete (UHPC) has more severe autogenous shrinkage than ordinary concrete, which may lead to increased cracking risks. Thus, a suitable and effective agent for internal curing (IC) of UHPC without a negative effect on the strength is needed to solve this problem. A type of strong and porous aggregate made of calcined bauxite was used in this study to achieve low shrinkage and lower-cement UHPC based on the modified Andreasen and Andersen model, and together, a reference mixture made of basalt aggregate was prepared. The autogenous shrinkage of UHPC with basalt aggregate reached at the age of 28 days, while the autogenous shrinkage of the UHPC with calcined bauxite was substantially reduced or a slight expansion occurred. This was found to be due to the internal curing effect provided by the calcined bauxite aggregate. A pronounced 56-day compressive strength of 148 MPa was achieved for this standard-cured UHPC without steel fibers. The low shrinkage UHPC internally cured by calcined bauxite aggregate can be applied to on-site cast UHPC structures or bridge decks that are prone to shrinkage cracking.
Internal Curing by Porous Calcined Bauxite Aggregate in Ultrahigh-Performance Concrete
Liu, Yalin (author) / Wei, Ya (author)
2020-12-29
Article (Journal)
Electronic Resource
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