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(a) Mortar Materials. Cementitious materials used in mortars shall conform to the requirements of the following applicable standard specifications:
(1) Quicklime for Structural Purposes, A.S.T.M. C5-59.
(2) Hydrated Lime for Structural Purposes, A.S.T.M. C6-49.
(3) Hydraulic Hydrated Lime for Structural Purposes, A.S.T.M. C141-67.
(4) Natural Cement, A.S.T.M. C10-64.
(5) Masonry Cement, Federal Specifications, SS-C-181b.
(6) Portland Cement, A.S.T.M. C-150-67.
Aggregate for mortar shall conform to the requirements of the Tentative Specification for Aggregate for Masonry Mortar, A.S.T.M. C144-66.
Water used in mixing mortar shall be clean and free from deleterious amounts of acids, alkalis or organic materials. (Note: Water suitable for drinking purposes is satisfactory.)
(b) Mortar Requirements. Mortar, as delivered to the mason, shall have a flow after suction for one minute, or not less than sixty-five percent of that immediately before suction. The flow shall be determined by the Water Retention Test of the Federal Specifications for Masonry Cement, SS-C-181b.
(1) Mortar used in masonry construction shall be classified as follows:
Minimum Compressive Strength of 2" Cubes at 28 days (psi)
(2) Unless the strength classification of the mortar has been otherwise established by test as prescribed in paragraph (b)(3) hereof, mortars of the following proportions, with the aggregate measured in a damp and loose condition, may be assumed to meet the strength classification given in paragraph (b)(1) hereof.
Proportions by Volume
Hydrated Lime or Lime Putty Allowable Range
Aggregate Measured in a Damp and Loose Condition
0 to 1/4
Not more than 3
1 (masonry FS* Type II)
9 to 1-1/4
Not more than 6
1 (masonry FS* Type II)
2 to 2-1/2
Not more than 9
0 to ½ Portland
1 to 1-1/4
Not more than 3 parts for each part cementitious material
(3) Mortar of materials conforming to the requirements of paragraph (b)(1) hereof and of any proportions conforming to paragraph (b)(2) hereof may qualify as mortar of any one of the four types, provided it conforms to the physical requirements of paragraphs (b)(1) and (2) hereof.
When it is desired to establish the strength classification of a given mortar by test, the strength shall be determined with mortar prepared in a testing laboratory, or representative materials, and in the proportions proposed for use. The test cubes shall be molded, cured and tested for compressive strength as described in the Federal Specification for Masonry Cement, SS-C-181b, except that for Type D mortar, the entire curing shall be in a laboratory air at seventy degrees Fahrenheit, plus or minus five degrees.
(c) Type of Mortar Required. Masonry shall be laid in Type A, Type B or Type C mortar, except as follows:
(1) Type A or Type B mortar shall be used in footings, foundation walls of solid masonry units, isolated piers, load-bearing or exterior walls of hollow masonry units, hollow walls of masonry, and cavity walls ten inches in nominal thickness, or more.
(2) Type D mortar may be used in solid masonry walls, other than parapet walls or rubble stone walls, not in contact with the soil and not less than twelve inches thick nor more than thirty-five feet in height, provided the walls are laterally supported at intervals not exceeding twelve times the wall thickness.
(3) Gypsum partition tile and block shall be laid in gypsum mortar. Nonbearing partitions and fireproofing of structural clay tile may be laid in gypsum mortar. Fire brick shall be laid in fire clay or air-setting mortar.
(4) Glass block when laid in mortar shall be laid in Type B mortar.
(d) Mortar Mix. As used in connection with the above-mentioned masonry unit, the mortar mix shall be as follows:
(1) For all masonry below grade, the mortar mix shall be one part cement to three parts sand. Lime equal to not more than fifteen percent of the cement by volume may be added.
(2) For all other masonry work, the mortar mix shall be one part cement to one part lime putty to six parts sand by volume; or prepared mortar mix and used in accordance with the manufacturer’s directions.
(3) Prepared mortar-mix cement may be used in place of cement and lime when the mortar meets the ASTM specifications for Type I and II masonry cement mortar.
(e) Joints. The joints between masonry units shall be not more than one-half inch thick. All outside and exposed joints shall be weathered or tooled, unless otherwise approved by the Inspector. All joints shall be pointed with mortar on both sides of the wall.
(Ord. 42-1981. Passed 2-23-81.)