System of protecting the edges of cast-in-place concrete slab on ground, construction joints

An improved form assembly for use in the construction of concrete slabs and protection of joints in said concrete slabs after construction, the assembly placed on a ground surface defining a generally flat reference plane, the assembly comprising:

• a longitudinal joint rail, the longitudinal joint rail comprising a first steel bar and a second steel bar, the steel bars formed of cold rolled steel bar sections and each having a major latitudinal dimension and a minor latitudinal dimension, the major latitudinal dimension, when in situ, extending generally perpendicular to the reference plane and the minor latitudinal dimension, when in situ, extending generally parallel to the reference plane, the steel rails being oriented, when in situ, with the major latitudinal dimensions thereof adjacent each other;
• connectors that connect the joint rails in contact with one another, said connectors also including release elements that release the joint edge members from each other under the force of the slabs shrinking during hardening thereby forming releasable joint therebetween;
• a temporary formwork along the joint rail and supporting the joint rail above the ground surface;
• a plurality of mounting brackets connecting the joint rail to the temporary formwork, the mounting brackets secured to the formwork and secured to the joint rail;
• and
• a plurality of studs extending from each side of the form assembly into the regions where the adjacent slabs are to be poured.

A method of forming an improved joint edge utilizing an improved joint edge assembly, for the construction of jointed concrete slabs and protection of concrete slab joints, the concrete slabs shrinking after pouring, the assembly comprising a first elongated joint edge member, a second elongated joint edge member, a plurality of anchors extending from each side of the form assembly into the regions where the adjacent slabs are to be poured, connectors that connect the joint edge members to each other, said connectors also including release elements that release the joint edge members from each other under action of the slabs shrinking during hardening, and a dowel aligner connected to temporary formwork, extending into the region where the first concrete slab is to be poured, whereby the dowel aligner permits the placement of dowels prior to the pouring of the adjacent concrete slab, the method comprising:

• placing the assembly of the joint edge members and connecting means for the joint edge members to form and thereby protect edges of a concrete slab joint, pouring the slabs to the joint edge members, and
• allowing the joint edge members to release from each other under action of the slabs shrinking during hardening with the anchors embedded therein and under action of the releasing elements of the connectors, allowing the joint formed by the joint edge members to open and minimize slab cracking at and adjacent to the joint during shrinkage and subsequently protecting the joint edge.