Title

Factorial Design and Optimization of Ultra-High-Performance Concrete with Lightweight Sand

Abstract

In this study, lightweight sand is used as an internal curing agent in ultra-high-performance concrete (UHPC). A factorial design approach was employed to evaluate the effects of multiple mixture proportioning parameters that are important for mixture optimization of UHPC. The investigated mixture design parameters included the substitution volume ratio of lightweight sand for river sand (LWS/NS: 0 to 25%), the cementitious materials-To-sand volume ratio (cm/s: 0.8 to 1.2), and the water-cementitious materials ratio (w/cm: 0.17 to 0.23). The evaluated properties included fresh properties, compressive strengths at up to 91 days, and autogenous shrinkage at up to 28 days. Statistical models that take into account the coupling effects of mixture proportioning parameters were formulated to predict the UHPC properties. The w/cm and LWS/NS were the most significant parameters influencing the compressive strength and autogenous shrinkage, respectively. By replacing the river sand with 25% lightweight sand, the compressive strength at 91 days increased from 150 to 170 MPa (22.5 to 25.5 ksi) and the autogenous shrinkage at 28 days decreased from 410 to 70 μm/m (410 x 10-6 to 70 x 10-6 in./in.). The mixture with w/cm of 0.23, LWS/NS of 0.25, and cm/s of 1.2 is determined as the optimum UHPC mixture. The material properties of the mixture: The HRWR demand was 0.6%, the 28-day autogenous shrinkage was 260 μm/m (260 x 10-6 in./in.), and the 91-day compressive strength was 147 MPa (22.1 ksi).

Department(s)

Mathematics and Statistics

Second Department

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Compressive strength; Concretes; Curing; Light weight concrete; Mixtures; Sand; Shrinkage; Autogenous shrinkage; Factorial design; Internal curing; Rheological property; Ultra high performance concretes; High performance concrete; Lightweight sand; Rheological properties; Ultra-high-performance concrete (uhpc)

International Standard Serial Number (ISSN)

0889-325X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 American Concrete Institute (ACI), All rights reserved.

Share

 
COinS