Development of a Non-Destructive Evaluation Practice of Installed Weatherproofing Sealant Joints Using a Rolling Device—An Introduction to ASTM C 1736

ABSTRACT: This paper provides an overview of the development of stand­ardized methodology to evaluate joint seal continuity, encompassed in the newly published ASTM C 1736-11, “Standard Practice for Non-Destructive Evaluation of Adhesion of Installed Weatherproofing Sealant Joints Using a Rolling Device.” This standard practice was created under the jurisdiction of ASTM Committee C 24 on Building Seals and Sealants and is the direct responsibility of Subcommittee 30 on Adhesion; it was approved July 1,

2011. Fundamental details contributing to the successful usage of this prac­tice are examined by answering the following questions: Where exactly do the stresses produced by this procedure have an effect upon the sealant-to – substrate bond-line? How does joint geometry impact this bond-line stress?

What level of stress on a bond-line provides usable information without dam­aging the seal?

KEYWORDS: ASTM C 1736, continuous sealant evaluation, cured, joint, non-destructive evaluation, rolling device, sealant failure in adhesion

Introduction

The development of a proposed standard practice for the “non-destructive eval­uation of adhesion of installed weatherproofing sealant joints using a rolling device" has been ongoing within ASTM Subcommittee C 24.30 for several years

and has now been published. The intent of this standard is to provide the con­struction industry with a field practice to facilitate the inspection of sealed joints such that the continuity of the seals can readily be determined.[29] A practi­cal means with which to assess adequate sealant performance in the field and determine the degree of bonding along the joint substrate following initial in­stallation, as well as for inspections carried out over the life of the jointing, has become of considerable interest in the construction community.

During the development of the standard, several issues emerged related to what actually occurs along the bond-line when a rolling device produces a mo­mentary strain in the sealant; more specifically, the following question were raised:

• How might the results obtained using the proposed method be affected by variations in joint geometry?

• Will applying the “rolling" device to the joint ultimately damage the seal (i. e., are the stresses induced along the bond-line by the device non­destructive, as indicated in the standard’s title)?

• What level of stress should be imposed on the bond-line in order to pro­duce usable information without damaging the seal?

Gaining an understanding of the basic principles that underscore the use of such devices while acquiring information on the degree of adhesion along the sealant bond-line permits the making of informed decisions with respect to use in practice. An attempt is made in this paper to answer some of the questions posed above.

It should be understood, though, that this paper is not about sealant mate­rial performance, nor is it the author’s intent to suggest any particular construc­tion design. In this paper, a brief overview is first provided regarding the rationale for the development of this method, including a perspective on a previ­ous standard method for assessing in-field performance, after which we discuss efforts within the ASTM Subcommittee C 24.30 to develop this new standard practice.