Masonry Magazine December 1988 Page. 16
Mortar containing calcium chloride shall not be added to mortar. Mortar colors may be added to the mortar if specified. Mortar containing such colors shall conform to the physical requirements in Table 2.
Note 1-This specification is not applicable to extended-life mortars that are mixed under controlled conditions in a central batching plant.
4.5 Water. Water shall be clean and free of amounts of oils, acids, alkalies, salts, organic materials or other substances that may be deleterious to mortar or any metal in the wall.
5. REQUIREMENTS
5.1 Proportion Specifications. Mortar conforming to the proportion specifications shall consist of a mixture of cementitious material, aggregate and water all conforming to the requirements of Section 4 and shall be proportioned within the limits given in Table I for each mortar type specified. See Appendix A.1 for a guide to the selection of mortar type.
5.1.1 Mortar of a known higher compressive strength shall not be substituted where a mortar type of an anticipated lower compressive strength is specified without the consent of the specifier.
5.2 Property Specifications. Mortar conformance to the property specifications shall be established by test of laboratory prepared mortar in accordance with Section 6 and 8.2. The laboratory prepared mortar shall consist of a mixture of cementitious material, aggregate and water all conforming to the requirements of Section 4. The physical properties of the laboratory prepared mortar shall conform to the requirements of Table 2. See Appendix A.1 for a guide to the selection of mortar type.
5.2.1 No change in the laboratory proportions established for mortar accepted under the property specifications shall be made, except for the quantity of mixing water. Materials with different physical characteristics shall not be used in the mortar prepared for the work unless compliance with the requirements of the property specifications is re-established and accepted by the specifier.
6. PHYSICAL PROPERTIES
6.1 Laboratory Prepared Mortar. Laboratory mortar samples prepared and tested in accordance with Section 7 shall conform to the physical requirements for each type specified as prescribed in Table 2.
6.2 Field Prepared Mortar. Field prepared mortar meeting the requirements of Sections 4 and 5 shall not be required to meet the physical requirements of Table 2. When quality control testing is specified, ASTM Standard C780 shall be used (see Note 2).
Note 2- The required properties of the mortar in Table 2 are for laboratory prepared mortar mixed with a quantity of water to produce a flow of 110-5 percent. This quantity of water is not sufficient to produce a mortar with a workable consistency suitable for laying masonry units in the field. Mortar for use in the field must be mixed with the maximum amount of water, consistent with workability, in order to provide sufficient water to satisfy the initial rate of absorption (suction) of the masonry units. The properties of laboratory prepared mortar at a flow of 11015 percent are intended to approximate the flow and properties of field prepared mortar after it has been placed in use and the suction of the masonry units has been satisfied. The properties of field prepared mortar mixed with the greater quantity of water, prior to being placed in contact with masonry units, will differ from the property requirements in Table 2. Therefore, the property requirements in Table 2 cannot be used as requirements for quality control of field prepared mortar. ASTM C780 may be used to measure consistency in field sampled mortar.
7. METHOD OF TESTING
7.1 Compressive Strength. Compressive strength shall be determined in accordance with ASTM Standard C109. The mortar shall be composed of materials and proportions that are to be used in the construction with mixing water to produce a flow of 110±5 percent.
7.1.1 Specimen Storage. Keep mortar cubes for compressive strength tests in the molds on plane plates in a moist room or cabinet meeting ASTM Standard C511 for 48 to 52 h in such a manner that the upper surfaces shall be exposed to the moist air. Remove mortar specimens from the molds and place in a moist room or cabinet until tested.
7.2 Water Retention. Water retention shall be determined in accordance with ASTM Standard C91, except that the laboratory mixed mortar shall be of the materials and proportions to be used in the construction.
7.3 Air Content. Determine air entrainment in accordance with Specification C91 except calculate the air content to the nearest 0.1% as follows (see Note 3):
D = (W1 + W2 + W3 + Vw) / (W1/P1 + W2/P2 + W3/P3 + Vw)
A = 100 - Wm / 4D
where:
D = density of air-free mortar, g/cm³,
W1 = weight of portland cement, g.
W₂ = weight of hydrated lime, g.
W3 = weight of sand, g.
VW = millilitres of water used,
P1 = density of portland cement, g/cm³,
P2 = density of hydrated lime, g/cm³,
P3 = density of sand, g/cm³,
A = volume of air, %, and
Wm= weight of 400 mL of mortar, g.
Note 3- The weights per cubic foot (kg/m³) of the materials are considered to be as follows:
Material Weight, Ib per cu ft (kg/m³)
Portland cement 94 (1504)
Hydrated lime 40 (540)
Sand, damp and loose 80 lb (1280) of dry sand
8. CONSTRUCTION PRACTICES
8.1 Storage of Materials. Cementitious materials and aggregates shall be stored in such a manner as to prevent deterioration or contamination by foreign materials.
8.2 Measurement of Materials. The method of measuring materials for the mortar used in construction shall be by either volume or weight, and such that the specified proportions of the mortar materials can be controlled