Effect of CaO and MgO based expansive agent on deformation and mechanical properties of concrete-filled steel tubes

The expansion of cement mortar mixing expansive agent under standard curing and membrane curing conditions and compressive strength in constrained conditions are studied in this paper. Results show that the early expansion effect of calcium sulphoaluminate hydrate-calcium hydroxide expansive agent is obvious, mid-to late effect of magnesia expansive agent increase clearly. Compare with standard curing, the shrinkage of the basic cement mortar increase and expansion effect of expansive agent reduce under membrane curing. The expansion effect of expansive agent B is good and persistent under membrane curing, its applicable to used in the closed environment, such as concrete filled steel tubes. The compressive strength of mortar with expansion agent is a little more than the basic mortar under the condition of limit.

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Experimental Study of Performance of Self-Stress Lightweight Aggregate Concrete Filled Steel Tubes after Exposure to Fire

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.790.173 ◽

2013 ◽

Vol 790 ◽

pp. 173-176

Author(s):

Jin Can Xu ◽

Peng Fei Ren ◽

Hai Lun Tong ◽

Xin Tang Wang

Keyword(s):

Bearing Capacity ◽

Fire Behavior ◽

Lightweight Aggregate ◽

Lightweight Aggregate Concrete ◽

Fire Load ◽

Steel Tubes ◽

Aggregate Concrete ◽

Expansive Agent ◽

Short Columns ◽

Concrete Filled Steel Tubes

The post-fire behavior of a set of self-stress lightweight aggregate concrete filled steel tubular short columns (noted as SSLC-SSC) after exposure to fire was experimentally studied. Effect of the maximum value of fire response temperatures of the tubes and their geometric parameters on the strength and the other mechanical property of the specimens were especially discussed. The experimental results show that the specimens of SSLC-SSC have higher post-fire bearing capacity and better plastic deformation, there was no obvious descent segment in post-fire load-displacement curves of the most specimens subjected to fire load. It was concluded that the maximum response temperature of specimens has great effect on the post-fire bearing capacity of self-stress concrete-filled steel tubes subjected to fire load, and the value of self-stress corresponding to 10% of dosage of expansive agent has the greatest effect on post-fire bearing capacity of specimens of SSLC-SSC.

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Research on Mechanical Properties of Separation Concrete-Filled Steel Tubes Subjected to Eccentric Compression on Non-Separation Side

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.117-119.887 ◽

2011 ◽

Vol 117-119 ◽

pp. 887-892 ◽

Cited By ~ 4

Author(s):

Xia Ping Liu ◽

Zhuo Sun ◽

Hai Yun Huang ◽

Shu Tang ◽

Chun Hui Tang

Keyword(s):

Mechanical Properties ◽

Load Capacity ◽

Eccentricity Ratio ◽

Steel Tubes ◽

Ultimate Load Capacity ◽

Whole Process ◽

Short Columns ◽

Separation Ratio ◽

Eccentric Compression ◽

Concrete Filled Steel Tubes

This document deals with the whole process compression model test on 12 short columns of separation concrete-filled steel tubes (CFST) which are subjected to eccentric compression on the non-separation side. The experimental parameters include the separation ratio and the eccentricity ratio. The results show that the separation ratio and the eccentricity ratio will influence CFST components’ mechanical properties which contain the relationship of load-strain amd load-deformation, that especially embodied in the nonlinear stage. When compressed on non-separation side, the confinement of steel tubes to core concrete will be continuously weakened and the ultimate load capacity of the components will be decreased obviously with both the separation ratio and the eccentricity ratio increasing gradually. But it less serious which compare with that compressed on separation side.

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