MASCO Catalog: Construction Liquid and Powder

116 MASONS SUPPLY COMPANY Oregon (800) 537-3407 ♦ Washington (800) 537-6216 ♦ www.MASCO.net Clackamas | Eugene | West Eugene | Hillsboro | Medford | Portland | Salem | Ridgefield | Seattle | Tacoma | Woodinville Construction Joint Sealants - are produced in a wide variety of base materials each with different characteristics and properties designed for specific or multi-purpose uses. The sealants most frequently used in concrete and masonry joints subjected to movement are: polyurethane and silicones. Joints not subject to movement like control joints, semi- rigid epoxies are recommended. Most joint sealant problems are due to using the wrong type of sealant, poor design, or improper preparation and application. Successful expansion joints using elastomeric sealants are installed twice as wide as the depth. Controlling sealant depth and preventing joint disintegration is accomplished by using a polyethylene backer rod. The diameter of the rod should be 25 % larger than the joint’s width. Using the rod eliminates placing bond breaking strips before application of sealant and protection from disintegration caused by direct contact between asphaltic materials and sealant. Preparation is important if the sealant is to adhere properly. Laitance and loose material should be removed from the sides of the joint. The joint should be clean and dry, with a primer used for underwater application or hard to bond to surfaces. Check with sealant literature for recommendations. The temperature at the time of installation of the sealant is important. Sealants should be installed at a moderate temperature so that the joint will not be fully opened or closed. The temperature will also affect the quantity of sealant required and can significantly influence the stress and strain on the sealant. Semi-rigid Epoxy Joint Sealants – are 2 component epoxy resin systems either self leveling or non sag consistency with a shore A hardness of between 70 to 90 with low bond and tensile strengths. This rigidity helps protect the edge of concrete by absorbing the impact of the hard wheels and by filling the entire joint increasing the impact resistance by the materials ability to stay in place under wheel loads. Semi-rigid epoxy sealants are designed to have a lower tensile and bond strength than concrete which eliminates structurally bonding the concrete together. The weakest link will give if too much movement occurs, in this case the epoxy bond line. This prevents the concrete from cracking and unraveling. Semi-rigid epoxy joint sealants are typically used in industrial floor applications as control joint fillers, or as security pick proof sealants. EXPANSION & JOINT SEALANT GUIDE Expansion / Control Joint Sealants