Title

Change in Fresh Properties of High-Strength Concrete Due to Pumping

Abstract

Pumping of high-strength concrete (HSC) in high-rise or long-span structures is of paramount importance in constructions. However, pumping technology in practice is highly dependent on practical field experience, and full-scale testing that is carried out for complex projects involving new materials or long pumping distances. In this paper, a long pumping circuit was built to study changes in fresh properties of HSC due to pumping. In total, 10 HSC mixtures with strength grades of C60 to C100 were pumped at constant flow rates in pipelines measuring 348, 600 and 924 m in length. Rheological properties, workability characteristics, and concrete temperature were measured on concrete specimens sampled before and after pumping. Rheological properties of concrete sampled in dismantled pipes shortly after the end of pumping were also determined. Test results indicated that the yield stress increased, the initial tangential viscosity decreased and the shear-thickening phenomenon was eliminated due to pumping. The increase in yield stress mostly occurred in the first half of the pipeline, and the tangential viscosity decreased nearly linearly along the pipe length. The levels of drop in initial tangential viscosity were found to positively correspond to the calculated shearing energy, which is estimated given the shear rate, apparent viscosity and elapsed time during agitation and pumping.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

The presented work was financial supports by National Key R&D Program of China (contract No. 2017YFB0310100), National Natural Science Foundation of China (contract Nos. 51778629 and 51922109).

Keywords and Phrases

High-Strength Concrete; Pumping; Rheological Properties; Workability

International Standard Serial Number (ISSN)

0950-0618

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2021 Elsevier, All rights reserved.

Publication Date

20 Sep 2021

Share

 
COinS