The weakest points in concrete pavement systems are the concrete joints. They are man-made cracks that allow for temperature-related expansion and contraction of concrete slabs. Sealants are commonly used in pavement joints to keep debris, deicing chemicals, and moisture out of the joint. When a joint sealant fails, the pavement can quickly deteriorate; however, when a joint sealant functions well, the pavement maintains its intended performance. Joint sealants are subjected to two forms of mechanical loads in the field: 1) as slabs contract or expand, the sealant is subjected to tension or compression, respectively; and 2) heavy vehicles travel over the joint and deflect the ends of the pavement slabs, causing sealants to shear. Sealants may also be exposed to a range of environmental factors, such as moisture and ultraviolet radiation. In this research project, to simulate the joint sealant performance, samples were made by buttering the three different silicone sealants, namely Sealant 1, Sealant 2, and Sealant 3, between 1" x 1" x 3" Portland Cement Concrete dogbone-shape samples and 0.2" x 1" x 3" glass substrate samples were prepared according to VTM 90 and ASTM C1135, respectively. The tests were carried out employing an Instron Tensile Testing Machine and unique fixtures designed at Virginia Tech to impart mechanical loading. In comparison to Sealant 2, the results demonstrated that Sealant 1 can withstand larger stresses. All the concrete samples failed due to adhesive failure, whereas some of the Sealant 1 glass samples failed due to adhesive failure at low peak loads and others failed due to a combination of adhesive and cohesive failure. Glass samples of Sealant 2 on the other hand showed just cohesive failure. In case of Sealant 3, samples of both ASTM C1135 and VTM #90 showed adhesive failure and failed by showing reasonable strength. / Master of Science / Concrete pavements have a number of man-made joints that separate adjacent slabs. The purpose of these joints is to allow relatively free concrete expansion and contraction owing to changes in temperature and moisture. To ensure longevity of concrete, these joints must be sealed with a long-lasting material that can protect the joints from moisture, dust, and de-icing salts. The focus of this study is on silicone sealants, which have used for years as a joint sealant material. Three different silicone-based sealants were used. And two test methods, VTM-90, and ASTM C1135, were used to conduct the tensile testing. VTM-90 provides the test method to determine bond of silicone sealant to concrete mortar while ASTM C1135 gives the procedure for quantitative measure of tensile adhesion properties of structural sealants. ASTM C1135 In comparison to Sealant 2, the test results showed that Sealant 1 can withstand high loads. All the VTM-90 samples of Sealant 1, 2 and 3, failed because of adhesive failure, whereas some of the Sealant 1 ASTM C1135 samples failed because of adhesive failure at low peak loads and others because of a combination of adhesive and cohesive failure. On the other hand, ASTM C1135 samples of Sealant 2 showed only cohesive failures while Sealant 3 samples showed adhesive failure.

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