Experimental Study on Deformation Behavior and Compressive Strength of Concrete Cast in Steel Tube Arches under Low-Temperature Conditions

Tuo Shi,Wen Xu,Xiao Guo,Nianchun Deng,Shi Wang

doi:10.1155/2020/8016282

Abstract

Taking the construction of a concrete-filled steel tube (CFST) arch bridge (part of the Sichuan-Tibet Railway) in low temperatures as the test site, firstly the deformation performance test of concrete was carried out. Following this initial testing, measurement of compressive strength and shrinkage performance was conducted in large-diameter CFSTs under a variety of curing conditions. Experimental results showed that the expansion effect of Ca-Mg composite expansive agent in concrete was better than that of other expansive agents at any stage. Under low-temperature curing (0°C), the sampling strength of the large-diameter CFSTs reached 73.5% of the design strength at 28 d in the presence of a nonthermal curing system. The design strength itself was reached, when a curing system involving a thermal insulation film was applied, and use of this film also led to improvements in concrete shrinkage. The results suggested that a Ca-Mg composite expansive agent, combined with an insulation film curing system, should be the technique selected for concrete pumping construction of CFST arch bridges in Tibet.

Highlights

Constructing bridges with the use of concrete-filled steel tube (CFST) arches is a rapidly developing technique in China and is blessed with clear economic advantages when used in certain span sizes [1, 2]
Marzouk and Hussein [4] tested the compressive strength of high-strength concrete at different curing temperatures and found it was proportional to curing temperature
ElHassan et al [8] studied the properties of alkali-activated slag concrete under different curing systems and found that indirect water curing could improve the compressive strength, while Zhang et al [9] found that raising curing temperature from 5°C to 50°C accelerated cement hydration

Summary

Introduction

Constructing bridges with the use of concrete-filled steel tube (CFST) arches is a rapidly developing technique in China and is blessed with clear economic advantages when used in certain span sizes [1, 2]. E research on the development law of deformation performance and strength of concrete in pipes under low temperatures can provide basis for the selection of construction time and concrete material in pipes of CFST arch bridges in Tibet. Marzouk and Hussein [4] tested the compressive strength of high-strength concrete at different curing temperatures and found it was proportional to curing temperature. Dong et al [12] studied the compressive properties of new antifreezing concrete, cured at different subzero temperatures, and considered that the strength of the concrete made with the new antifreezing agent complied with relevant performance requirements. E CFST specimen was taken as the research object in this study, and the curing temperature was strictly controlled, as well as the strength of concrete in different ages was tested. Concrete in pipes was sampled and tested according to Technical Specification for Testing Concrete Strength by the Core Drilling Method (JGJ T 384-2016). e results showed that insulated curing at low temperatures was beneficial to the strength of concrete. is study was developed with the intention of providing reference information for the construction of CFST-based concrete arch bridges in winter

Materials and Methods

Results and Analysis

Conclusions