A Dual Concentric Ring Test for Evaluating Residual Stress Development due to Restrained Volume Change

Abstract

A new test is being developed to evaluate the performance of concretes undergoing both expansion and shrinkage during hydration and/or temperature changes under mechanically restrained conditions. The standard restrained ring test (ASTM C1581-09) is a simple, economical method to evaluate a concrete mixture’s susceptibility to develop shrinkage cracking when it is restrained. The standard test only provides restraint against samples that shrink at isothermal temperature and cannot be used to characterize materials undergoing expansion. Further, the conventional restrained ring test is difficult to apply in cases in which the concrete undergoes large variations in temperature since the restraint changes dimension under heating and cooling. This paper describes a test that was designed to overcome both of these limitations. The new dual concentric ring test provides restraint for both shrinkage and expansion and has incorporated the ability to study thermal stresses by using a restraining ring having a very low thermal expansion coefficient. This paper will discuss the design and construction of the test device and will present preliminary data that characterizes its ability to quantify and evaluate restrained expansive, shrinkage, and thermal stresses.

Performance of Portland Limestone Cements: Cements Designed to Be More Sustainable That Include up to 15% Limestone Addition

“…The dual ring testing device consists of two instrumented concentric invar restraining rings that operate in an insulated chamber (54,55). In this test, a mortar specimen was cast between the inner and outer rings in two lifts, being vibrated with a handheld vibrator after each lift then trowel finished upon completion.…”

Cracking, Bond, and Durability Performance of Internally Cured Cementitious Grouts for Prefabricated Bridge Element Connections

“…Cracking propensity was assessed using a dual ring test (DRT) [16]. An AASHTO specification describing this test has recently been developed [17].…”

“…Given the potential benefits that the inclusion of IC might provide in cementitious grouts used as PBE connections, the team decided to extend upon the prior study and perform additional tests to assess the IC effect on properties relevant to PBE grout connections, namely cracking propensity, interfacial bond, and durability. This paper uses novel experimental techniques such as the dual ring test [16,17], formation factor concepts [18,19], and microstructural analysis to evaluate improvements in performance. These techniques help investigate how IC may lead to more robust and longer-lasting PBE connections.…”

Increased Use of Fly Ash in Hydraulic Cement Concrete (HCC) for Pavement Layers and Transportation Structures

“…Recently, new tests have been developed to use the dual ring specimen geometry to assess residual tensile stress and compressive stress development. While the dual ring was initially used for paste at isothermal conditions, a recent project with INDOT enabled the Purdue-NIST team to develop a dual ring setup that can be used for concrete under a variety of temperature conditions (isothermal, adiabatic, or specified) and which enables tensile and compressive residual stress and cracking potential to be assessed (Schlitter, Bentz, & Weiss, 2010;Schlitter, Senter, Bentz, Nantung, & Weiss, 2010).…”

“…Two series of dual ring tests (Schlitter, Senter, Bentz, Nantung, & Weiss, 2010) will be performed. The first series (isothermal) holds the temperature constant for 2 d, 4 d, and 7 d, at which time the temperature is subsequently reduced at a rate of 2uC/h until a temperature of -9uC is reached.…”