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8/06/2020 <br /> <br />04 01 20 MASONRY REPAIR Page 5 of 9 <br />2.3 MORTAR MIXES <br />A. Mixes: Mix mortar materials in the following proportions: <br />1. Provide mortar mix proportions that will not exceed the tested compressive strength of <br />existing mortar. If the contractor wants to utilize a mortar with a higher compressive <br />strength than specified, they must confirm compressive strength of existing mortar <br />through mortar analysis/testing. <br />2. Mortar by Type: ASTM C 270, Proportion Specification, Type N unless otherwise <br />indicated; with cementitious material limited to portland cement and lime. <br />3. Pigmented, Colored Mortar: Add mortar pigments to produce exposed, setting <br />(rebuilding) mortar and repointing mortar of color(s) required. <br />B. Measurement and Mixing: Measure cementitious materials and sand in a dry condition by <br />volume or equivalent weight. Do not measure by shovel; use known measure. Mix materials in <br />a clean, mechanical batch mixer. Use of pre-mixed mortar is acceptable as long as it is used to <br />create the approved sample. <br />C. Colored Mortar: Produce mortar of color required by using specified ingredients. Do not alter <br />proportions specified, or determined based on approved samples without Designer approval. <br />1. Mortar Pigments: Where mortar pigments are indicated, do not add pigment exceeding 10 <br />percent by weight of the cementitious or binder materials, except for carbon black which <br />is limited to 2 percent, unless otherwise demonstrated by a satisfactory history of <br />performance. <br />D. Do not use admixtures in mortar unless otherwise indicated. <br />2.4 ACCESSORY MATERIALS <br />A. Setting Buttons and Shims: Resilient plastic, nonstaining to masonry, sized to suit joint <br />thicknesses and bed depths of masonry units, less the required depth of pointing materials <br />unless removed before pointing. <br />B. Masking Tape: Nonstaining, nonabsorbent material; compatible with mortar, joint primers, <br />sealants, and surfaces adjacent to joints; and that easily comes off entirely, including adhesive. <br />C. Repair Mortar: Provide a polymer-modified, fast-setting Portland cement repair mortar that is <br />supplied in a factory-proportioned unit and can be used on vertical masonry surfaces. Product <br />shall be capable of stopping pressure leakage of water and shall have a rapid set time. Basis of <br />design, SikaSet Plug, or approved equal. <br />D. Joint Sealant: Refer to Section 07 92 00 – Joint Sealants for joint sealant and accessory <br />materials. <br />DocuSign Envelope ID: 7D9ACD4F-8F6C-42B6-9ADB-C60032DB6D03