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Abstract
The decay of waterproofing materials is one of the most critical and important factors concerning the durabilty of roof coverings. In this sense, to evaluate the membrane waterproofing durability the present European standard tests are mainly based on the measurement of the differences in mechanical properties (cold bending as well as ultimate tensile strength and elongation) between aged and unaged membranes. This paper deals with experimental tests aimed at gaining further information about the basic degradation process that cannot be given by conventional membrane tests. This was achieved by comparing the results obtained from current testing methods (followoing UEAtc guidelines and UNI standards) and those of Dynamic Mechanical Analyses (DMA, carried out with a Rheometrics RDA II apparatus according to ASTM D 4065-93 guidelines for plastic materials). The accelerated aging process was performed by submitting samples ofwaterproofing membrane and its constituent compound (bitumen modified with polymers) to 70C and 80C of thermal exposure for different perios of time. In order to evaluate and monitor the effect of thermal stress on the material's degradation, the property measurements were performed after 28, 90, and 180 days. The curves obtained from DMA have provided intersting information about membrane thermo-mechanical behavior and the effects of aging upon it. The peak of damping vs. temperature curves showed significant displacements towards higher temperatures as long as the aging of the waterproofing membrane continued, and these results can be related to the changes that occur in the micro-structure of the membrane compounds. Moreover, the aged and unaged membrane damping vs. temperature curves are related to the type and content of polymer and other components in the examined compounds, and what is obtained from the individual analysis of them (e.g., bitumen, polymers). The results therefore show that the Dynamic Mechanical Analysis (DMA) is a reliable test for the characterization of polymer modified bituminous membranes, that can be used to evaluate the ability of the membrane to withstand agents of aging.
The decay of waterproofing materials is one of the most critical and important factors concerning the durabilty of roof coverings. In this sense, to evaluate the membrane waterproofing durability the present European standard tests are mainly based on the measurement of the differences in mechanical properties (cold bending as well as ultimate tensile strength and elongation) between aged and unaged membranes. This paper deals with experimental tests aimed at gaining further information about the basic degradation process that cannot be given by conventional membrane tests. This was achieved by comparing the results obtained from current testing methods (followoing UEAtc guidelines and UNI standards) and those of Dynamic Mechanical Analyses (DMA, carried out with a Rheometrics RDA II apparatus according to ASTM D 4065-93 guidelines for plastic materials). The accelerated aging process was performed by submitting samples ofwaterproofing membrane and its constituent compound (bitumen modified with polymers) to 70C and 80C of thermal exposure for different perios of time. In order to evaluate and monitor the effect of thermal stress on the material's degradation, the property measurements were performed after 28, 90, and 180 days. The curves obtained from DMA have provided intersting information about membrane thermo-mechanical behavior and the effects of aging upon it. The peak of damping vs. temperature curves showed significant displacements towards higher temperatures as long as the aging of the waterproofing membrane continued, and these results can be related to the changes that occur in the micro-structure of the membrane compounds. Moreover, the aged and unaged membrane damping vs. temperature curves are related to the type and content of polymer and other components in the examined compounds, and what is obtained from the individual analysis of them (e.g., bitumen, polymers). The results therefore show that the Dynamic Mechanical Analysis (DMA) is a reliable test for the characterization of polymer modified bituminous membranes, that can be used to evaluate the ability of the membrane to withstand agents of aging.
Date
6/1998
6/1998
Author(s)
A Tiso; G Pasetto; M Favaro; G Satta; S Croce; E Deangelis
A Tiso; G Pasetto; M Favaro; G Satta; S Croce; E Deangelis
Page(s)
310-324
310-324
Keyword(s)
polymer; modified bitumen; durability; accelerated aging; dynamic mechanical analysis
polymer; modified bitumen; durability; accelerated aging; dynamic mechanical analysis