System of protecting the edges and construction joints of cast in place concrete slabs

For use in constructing hardened first poured and second and later poured substantially horizontal concrete slabs, each having an upright edge, on a slab support surface, said edge being at least at times in abutting contact with each other, wherein said slabs have interfacing protective elongated first and second upper joint edge members, wherein said concrete slabs are of a type that shrink during hardening of poured wet concrete that form said concrete slabs, said upright edge of said second slab having been physically formed and supported by the upright edge of said first slab, an upper joint edge construction assembly for constructing said first and second concrete slabs and interfacing upper joint edge members, said assembly comprising:

• said first elongated rigid joint edge member for providing a first protective upper edge joint member along said upright edge of said first poured concrete slab after pouring and hardening of said first poured concrete slab,
• said second elongated rigid joint edge member for providing a second protective upper edge joint member along said upright edge of said second poured concrete slab after pouring and hardening of said second poured concrete slab,
• said first and second elongated joint edge members each having initially attached abutting sides and non-abutting sides, said initially abutting sides of each of said elongated rigid edge members being releasably attached together before pouring wet concrete to form said first poured and said second poured concrete slabs,
• interference type connectors for releasably attaching the elongated joint edge members to each other, said interference type connectors having release elements that release the joint edge members from each other,
• a first rigid stud member rigidly secured to said non-abutting side of said first elongated joint edge member, said first stud member projecting laterally away from said first joint edge member and being embedded in said first poured concrete slab during pouring of said wet concrete and after hardening of said first poured concrete slab, and
• a second rigid stud member rigidly secured to said non-abutting side of said second elongated joint edge member, said second stud member projecting laterally away from said second joint edge member and later being embedded in said second poured concrete slab during pouring of said wet concrete and after hardening of said second concrete slab,
• said embedded stud members having forcibly pulled each of said elongated abutting sides of said joint edge members away from each other caused by shrinkage of both of said first poured and said second and later poured concrete slab for causing said abutting sides of said joint edge members, having been initially attached by said interference type connectors, to release from each other for forming space between said initially abutting sides of said first and second joint edge members, said release elements allowing said joint edge members to release from each other as said stud members pull said joint edge members away from each other and from abutting interconnection by said interference type connectors including said release during shrinkage of said concrete slabs, said joint edge members thereby forming protective rigid edges along and between said first poured and second and later poured concrete slabs.