The latter includes the rubber and steel joints in which the metal reinforcements are first treated to facilitate adhesion with the rubber (pickling and sandblasting) and then incorporated in the elastomer that complies with the ETAG 032 standard. All this takes place in molding phase which consists of a thermal vulcanization process in compliance with European standards (ISO); being completely covered by rubber, the sheets steel are protected from corrosion.
The excursion takes place by elastic deformation of the internal rubber parts, thanks to their particular geometry.
The structural passageway is overcome by the usually central sheet metal called the "bridge plate".
The anchoring to the structure is allowed by ‘L’ lateral plates (incorporated in the rubber) equipped with slots through which the threaded rods pass.
The advantages and characteristics of the steel-rubber expansion joints (MAT Joints) are:
- Absence of corrosion as the metal reinforcements are completely covered by rubber.
- Absorption of horizontal and transverse movements.
- Easy assembly.
- Easy and quick replacement of existing joints.
- Impermeability and excellent resistance to skidding of vehicles as the upper part of the joint, subject to transit, is machined so as to improve adherence with the tire and guarantee the rapid outflow of rainwater. The connection blocks with the bituminous flooring are made of fiber-reinforced mortar or with epoxy-polyurethane or similar elastic sealant.
The drainage of the water is also aided by the rubber flashing, located at the structural gap and by a 'U' shaped aluminum profile, placed upstream of the joint, which have, respectively, the purpose of picking up and conveying to the drain infiltration water.
- Long durability and maintenance not particularly expensive and difficult: the rubber compound used is appropriately treated to resist oils, greases, petrol, salts and sand, without undergoing premature aging caused by solar radiation, salt and snow.
