Mortar: Mix mortar in a mechanical mortar mixer for a minimum of 3 minutes, before using. Mix proportions shall be accurately followed on site. Place mortar within 1 12 hours after mixing. Retempering is not permitted.
Setting: Do not wet concrete units before laying. Remove any units, which are disturbed after mortar has stiffened, and re-lay with fresh mortar. Provide full mortar coverage (face and webs) around cells to be grouted and on starting courses on solid foundation walls. Clean cells to be grouted of any protruding mortar fins. Completely fill all horizontal face joints with mortar, furrowing slightly with trowel. Fill cross joints with mortar applied against the end of the block before setting tight to block already in place. Set units in running bond.
Mortar joints: Set units with 3/8 inch nominal mortar joints in accordance with modular coursing. Wipe off excess mortar from surface ofblock work before mortar sets. Tool mortar joints exposed to view (whether or not the surface is to receive a paint or other coating which will reveal joints). Tool joints slightly concave, smooth and dense so the mortar will be fully compacted and pressed against the edges ofthe concrete units.
Cavity Wall Construction: Keep mortar out of cavity for the entire height of the wall and keep weeps elear.
Prepare foundations to assure surfaces to support concrete masonry are at the proper elevations and free of all dirt and other deleterious materials.
Mix grout a minimum of 5 minutes before using. Place grout within 1 12 hours after mixing. Solidly fill all cells containing reinforcing and where shown on Drawings. Maximum height of grout lift shall be 4 feet. Vibrate or rod (completely penetrating grout in cell with a rebar in an up and down motion) in-place grout while placing, and reconsolidate by further rodding after grout takes a plastic consistency, but before it takes initial set. Stop vertical lifts 1 Yz inches below the top of a course to form a key for the next lift. Be certain cells to be grouted are clean of debris and mortar droppings. Grout all horizontal masonry lintels and bond beams. Grout lintels in a continuous operation over the openings and the end bearings, as shown on Drawings. Clean off all grout spills from surface of work immediately, before grout has a chance to set.
5 Section 04220