Exploration of Mechanisms of Joint Deterioration in Concrete Pavements regarding Interfacial Transition Zone

Xin Wang,Kejin Wang,Jiake Zhang,Xuhao Wang,Peter Taylor,Xinjian Sun

doi:10.1155/2018/3295954

Abstract

As a common issue for cold weather regions, premature deterioration of concrete at joints has been reported in many states. In this paper, the mechanisms of joint deterioration were investigated, and then, experimental investigations were conducted to further verify some of the mechanisms. It was found that freeze-thaw (F-T) damage and salt crystallization are not enough to cause the observed deterioration, but the deterioration near the interfacial transition zone (ITZ) may be the cause of some of the observed phenomena. In the experimental work, samples were tested at 40°F in salt solutions to observe the deterioration in the ITZ using the scanning electron microscope (SEM). Concrete tested in MgCl2 solution indicated distress in ITZ under SEM. It was found that ITZ may act as a shortcut for ion transfer to surrounding concrete near the joints and may also be the weak point for cracking due to expansion of the paste.

Highlights

Sawn joints in concrete pavements are used to control both transverse and longitudinal cracking, which are induced by shrinkage or contraction of the pavement
It is likely that the damage is due to the paste expanding away from the aggregate particles. is type of deterioration was more prevalent closer to the face of the sample exposed to solution, which is consistent with distress being associated with solutions penetrating the system from an exposed face
For samples soaked in 3% MgCl2, whole aggregate particles were observed to be removed in several samples (a)

Summary

Introduction

Sawn joints in concrete pavements are used to control both transverse and longitudinal cracking, which are induced by shrinkage or contraction of the pavement. Contraction joints are normally made by saw cutting, with a minimum depth of 1⁄4 the thickness of slab but not less than 25.4 mm and a minimum width of 3.18 mm. Sealants may deteriorate and so allow water to penetrate the saw cut over time, increasing the risk of damage within the kerf. To control or eliminate such pavement deterioration, it is necessary to understand the mechanisms of joint damage. E objective of this research was to review the current state of knowledge of possible causes of joint deterioration and further investigate the mechanism behind this form of deterioration

Mechanisms of Joint Deterioration

Results and Discussion

Conclusion