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PART 2 - PRODUCTS <br />2.1 MASONRY UNITS <br />A. Hollow load -bearing concrete masonry units complying with ASTM C90, <br />grade N, type I. <br />2.2 MORTAR <br />A. Ingredients: <br />1. Portland cement: Comply with ASTM C150, type I. <br />2. Lime: <br />a. Provide hydrated lime complying with ASTM C207, or <br />quicklime complying with ASTM C5. <br />b. When quicklime is used, slake and then screen through a 16 <br />mesh sieve. After slaking and screening, but before <br />using, store and protect for not less than ten days. <br />3. Aggregate: Provide clean, sharp, well graded aggregate free from <br />injurious amounts of dust, lumps, shale, alkali, surface coatings, and <br />organic matter, and complying with ASTM C144. <br />4. Admixtures: Do not use admixtures unless specifically approved in <br />advance by the Architect. <br />5. Water: Provide water free from deleterious amounts of acids, alkalis, <br />and organic materials. <br />B. Mixing: <br />1. Provide mortar type "M" or type "S", as designated on the Drawings or <br />otherwise directed by the Architect, and in accordance with ASTM <br />C270. <br />2. Proportions: <br />a. For type "M" mortar, provide one part portland cement to 1/4 <br />part hydrated lime and 3-3/4 parts sand by volume. <br />b. For type "S" mortar, provide one part portland cement to 1/2 <br />part hydrated lime and 4-1/2 parts sand by volume. <br />3. Mechanically mix in a batch mixer for not less than three minutes, using <br />only sufficient water to produce a mortar which is spreadable and of a <br />workable consistency. <br />4. Re -temper mortar with water as required to maintain high plasticity. <br />a. On mortar boards, re -temper only by adding water within a <br />basin formed with mortar, and by working the mortar <br />into the water. <br />b. Discard and do not use mortar which is unused after 1-1/2 <br />hours following initial mixing. <br />5. Measure ingredients in mixing box measuring 12"x12"x12". Mortar <br />mixed without accurate proportions will be rejected. <br />04220-2 <br />