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1 6-20.2 Materials <br /> 2 <br /> 3 Masonry Unit Materials <br /> 4 <br /> 5 Masonry unit materials shall meet the following requirements: <br /> 6 <br /> 7 ASTM C90-85, Hollow Load Bearing Masonry Units. <br /> 8 <br /> 9 ASTM C140-75, Sampling and Treating Concrete Masonry Units. <br /> 10 <br /> 11 ASTM C145-85, Solid Load Bearing Concrete Masonry Units. <br /> 12 <br /> 13 Concrete wall units shall have a minimum net 28-day compressive strength of 3000 <br /> 14 psi. The concrete shall have a maximum absorption of 6 to 8 pounds per cubic <br /> 15 foot. <br /> 16 <br /> 17 Exterior dimensions may vary in accordance with ASTM C90-85. Units shall have <br /> 18 a minimum of 1 square foot face area each. The depth of the standard block shall <br /> 19 be a minimum of 21 inches. <br /> 20 <br /> 21 Standard block units shall provide a minimum of 150 psf of wall face area. <br /> 22 Fill which is contained within the dimensions of the units may be considered <br /> 23 as 80 percent effective weight. <br /> 24 <br /> 25 Units shall have angled sides capable of concave and convex alignment curves <br /> 26 with a minimum radius of 3.5 feet. Supply special units as required to execute the <br /> 27 design concepts. <br /> 28 <br /> 29 Units shall be interlocked with non-corrosive fiberglass (or as approved by the <br /> 30 ENGINEER) pins. Fiberglass connecting pins shall be '/2" diameter thermoset <br /> 31 lsopthalic polyester resin/pultruded fiberglass reinforcement rods. Pins shall have <br /> 32 a minimum flexural strength of 128,000 psi and short beam shear of 6400 psi. <br /> 33 <br /> 34 Units shall be interlocked as to provide a minimum of one inch setback per each <br /> 35 course of wall height (1:8 batter). <br /> 36 <br /> 37 Base Leveling Pad: <br /> 38 <br /> 39 Leveling pad materials shall be crushed surfacing top course and shall be placed <br /> 40 as shown on the plans upon undisturbed insitu soils, to a minimum thickness of 6 <br /> 41 inches. Crushed Surfacing Top Course pad shall be level so as to provide a level <br /> 42 hard surface on which to place the first course of units. Compaction shall be to 95 <br /> 43 percent maximum density. The leveling pad shall be prepared to insure complete <br /> 44 contact of retaining wall unit with base <br /> 45 <br /> 46 Unit Fill: <br /> 47 <br /> HAWTHORNE ELEMENTARY <br /> SAFE ROUTES TO SCHOOL <br /> FED AID#SRTS-0420(021); COE#3540 SP-74 March 16,2016 <br />