Experimental Observation on Variation of Rheological Properties during Concrete Pumping

Kyong Pil Jang,Seung Hee Kwon,Surendra P. Shah,Chan Kyu Park,Young Jin Kim,Myoung Sung Choi

doi:10.1186/s40069-018-0310-3

Abstract

Workability of concrete varies during pumping. Even though concrete satisfies the required workability before pumping, it often does not satisfy the required standard after pumping. Moreover, serious problem could happen such as segregation and blockage. In this study, the rheological properties of concrete change during pumping from the pressure distribution over the pipe length was investigated. The rheological properties and the pressures measured from seven different real-scale pumping tests with 116 m to 1000 m long pipelines and 24 MPa to 100 MPa concrete were analyzed. As a result, it was found that the rheological properties vary gradually along the pipeline, and could abruptly change inside the pump. The variation of rheological properties during pumping seems to be attributed in part to the increase of water absorption in aggregates under high pressure and the additional mixing effect, namely, intensive shearing under high pressure inside pump.

Highlights

The workability and rheological properties of concrete are changed during pumping (Choi et al 2016a; Feys et al 2016; Ko et al 2008, 2010; Kwon et al 2013; Kwon et al 2016; Secrieru et al 2018)
In the case of a large construction such as a high-rise building, the pressure and shearing due to pumping are so significant that the change of the rheological properties is great
This paper aims to analyze data on pressure within the pipe that is measured by performing pumping tests in order to understand how the rheological properties of concrete change

Summary

Introduction

The workability and rheological properties of concrete are changed during pumping (Choi et al 2016a; Feys et al 2016; Ko et al 2008, 2010; Kwon et al 2013; Kwon et al 2016; Secrieru et al 2018). In the case of a large construction such as a high-rise building, the pressure and shearing due to pumping are so significant that the change of the rheological properties is great. The hypotheses are still insufficient to explain all the phenomena observed in the real pumping

Objectives

Methods

Results

Discussion

Conclusion