Effect of Hybrid Fibers on Fresh Properties, Mechanical Properties, and Autogenous Shrinkage of Cost-Effective UHPC
This paper investigates the effects of hybrid micro-macro steel and micro steel blended with synthetic fibers and of the fiber content on key properties of a cost-effective ultrahigh-performance concrete (UHPC). Eleven mixtures are prepared using three types of fibers: micro steel straight fibers (SF), macro steel hooked-end fibers (HF), and polyvinyl alcohol (PVA) fibers. The fiber content of SF is increased from 0 to 5%. At a fiber content of 2%, different combinations of micro-macro steel and micro steel-PVA fibers are considered. The minislump flow of all mixtures is fixed to 280 ± 10 mm by adjusting the high-range water reducer (HRWR) dosage to ensure self-consolidating characteristics. The investigated properties include the HRWR demand, plastic viscosity, compressive strengths, tensile and flexural properties, and autogenous shrinkage. The plastic viscosity increases with the steel fiber content. At a fiber content of 2%, increasing the content of PVA or HF increases the plastic viscosity. Compared with the reference UHPC mixture made with 2% SF, the incorporation of 1% SF and 1% HF increases the flexural strength, toughness, and tensile strength by approximately 25, 30, and 20%, respectively, and reduces the autogenous shrinkage by 25%. The addition of 1.5% SF and 0.5% PVA increases the flexural strength and toughness by 10 and 15%, respectively, and decreases autogenous shrinkage by 40%. Increasing the SF content from 2 to 5% does not significantly improve the flexural properties, but notably reduces autogenous shrinkage.
W. Meng and K. Khayat, "Effect of Hybrid Fibers on Fresh Properties, Mechanical Properties, and Autogenous Shrinkage of Cost-Effective UHPC," Journal of Materials in Civil Engineering, vol. 30, no. 4, American Society of Civil Engineers (ASCE), Apr 2018.
The definitive version is available at https://doi.org/10.1061/(ASCE)MT.1943-5533.0002212
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Bending strength; Compressive strength; Concretes; Cost effectiveness; Fibers; Mechanical properties; Mixtures; Shrinkage; Tensile strength; Viscosity; High range water reducer; Hybrid fibers; Poly (vinyl alcohol) (PVA); Rheological properties; Self-consolidating concrete; Tensile and flexural properties; Ultra high performance concretes (UHPC); Ultrahighperformance concretes (UHPC); Steel fibers; Concrete; Mechanical property; Rheology; Shrinkage; Steel
International Standard Serial Number (ISSN)
Article - Journal
© 2018 American Society of Civil Engineers (ASCE), All rights reserved.
01 Apr 2018