Concrete Joints + Accesories Flashcards
Construction joints should be located @ points of:
min. shear
create a weak section,
direct location of cracking,
@ normal temp/stress.
Control Joint
@ 2 successive pours (plane of weakness is created)
Construction joints:
Construction joints form point where this can occur
water leakage
Formed by tooling wet/sawcutting/premolded sections in framework.
1/4th slab thickness.
Control Joint
Water leakage @ Construction Joints can be prevented using
waterstops, inserted 1st pour,
extend into 2nd pour.
allow sections move independently,
movement caused by shrinkage or temp changes.
cyclical movement, so must move in two directions.
Expansion joints
typ. expansion joint extends through
entire structure,
so no rigid connection between any 2 components of adjacent building sections.
typ. 2 pours separated w premolded joint material.
Isolation joints
proprietary products applied protect against water/weather/chemicals/dusting/or to harden.
Concrete Sealers
these type of sealers do not wear as well as some surface sealers do
can use to stop moisture/alkaline migration through existing slab
penetrating sealer
often used to separate columns from slabs and slabs from foundations.
Isolation joints
steel plates cast flush w surface.
attached to steel anchor extending into concrete for positive anchorage.
may be welded to rebar.
weld plates
Inserts (anchoring devices)
2 types Concrete Sealers
coating or penetrating
this type of sealer dries as surface film, made from acrylics, urethanes, epoxies
coating sealer
