03-12-1984 Council Packet - Laserfiche WebLink

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04200.4.2. Concrete Blocks: Concrete block shall be the sizes indicated on the plans, light gray or neutral color, and shall conform to the requirements of ASTM C90, Grade N, Type 1, hollow load bearing, normal weight units, and .. 1500 psi minimum compressive strength. All block shall be autoclave cured blocks. Exterior block ,nall be rockface or split face. Interior block shall be standard block. 04200.4.3. Mortar: Mortar for masonry units shall conform to ASTM C-476 and shall have a compressive strength of 2500 psi in 28 days, color as selected by the Engineer. Mortar shall be mixed in the proportions of one part Portland cement, 1/4 part hydrated lime and 3 parts sand by volume. The use of masonry cement in mortar will not be allowed. Air content of nortar shall not exceed 12 percent. No antifreeze liquids or salts shall be used in an attempt to lower the freez- ing point of the mortar. Calcium Chloride may be used to accelerate set only upon specific permission by the Engineer. If mortar color is added, it shall not exceed requirements of BIA MI-72. Water must be clean and free of dele- terious amounts of acids, alkalies or organic material. C4200.4.4. Grout: Grout shall comply with ASTM C94, and consist of one part Portland cement, 2-1/2 parts sand, two parts pea gravel and adequate water to produce a concrete of approximately ten inches slump and a minimum compression strength at 25 days of 3000 psi. 04200.4.5. Reinforcement Steel: Rebar shall be provided as indicated on the plans and in conformance with the requirements of Section 03200 of these spec- ifications. Wall reinforcement for single wythe concrete block walls shall be Dur-O-Wal, Richmond, or equal, with 2 - 3/16" diameter galvanized, side rods and #9 gal- vanized truss rods. Use prefabricated corner reinforcement at wall intersections. 04200.4.6. Other Materials: Items not described but required for a complete .. and proper installation of the work of this Section, shall be as selected by the Contractor subject to the approval of the Engineer. ..w 04200.5. INSTALLATION: 04200.5.1. Laying Block: All masonry units shall be laid plumb, true to line and with level and accurately spaced courses and joints. All partial block shall be neatly sawed with a masonry saw. All footing wall block may be laid with running bond. All other block shall w be stacked bond. Block units shall be placed with a full bed of mortar on all shell edges. ra: Units with open cells exposed in walls will not be permitted. All joints shall be uniform concave type joints and allowed to set until mortar is thumb print hard before tooling. Block rt corners shall be carefully cut with masonry saw. •� 04200-2 0-9693b M