PRODUCT NAME Mortar Cement: Type N, Type S, Masonry Information and Type M MORTAR CEMENT: PRODUCT DATA SHEET MANUFACTURER Represented by: Portland Cement Association (PCA) 5420 Old Orchard Road Skokie, IL 60077-1083 Voice: 847.966.6200 Fax: 847.966.9781 Internet: www.cement.org PRODUCT DESCRIPTION Basic Use: Mortar cement is spe- cially formulated and manufactured to produce masonry mortar for use in brick, block, and stone masonry con- struction. Mortar cement mortars have MORTAR AND MASONRY GROUT Mortar Cement similar attributes to masonry cement Portland Cement Portland Association mortars, but they have lower air con- Masonry constructed using mortar cement mortar and three brick colors conveys a sense tents than masonry cements, and the of security and permanence for students of the Buffalo High School in Buffalo mortar cement specification includes a Minnesota, designed by Abendroth, Rego & Youngquist. minimum bond strength requirement. 4 Mortar cement mortars are appropriate September 2002 for use in structural applications that Types: Mortar cements are produced ments of ASTM C 270. Requirements require masonry with high flexural in Type N, Type S, and Type M classifi- for sand to be used with mortar cement bond strength. cations for use in preparation of ASTM to produce ASTM C 270 mortars are Composition and Materials: Mortar Specification C 270 Type N, S, or M found in ASTM C 144. cement consists of a mixture of portland mortar, respectively, without further Physical Properties: Mortar cement cement or blended hydraulic cement addition of cements. mortars conform to the physical proper- and plasticizing materials (such as lime- Table 1 is a general guide for selec- ties listed in Table 2. stone or hydrated lime), together with tion of mortar type. Other factors, such These property requirements assure other materials introduced to enhance as type and absorption of masonry unit, consistent performance of the product one or more properties such as setting climate and exposure, applicable build- with respect to bond strength, compres- September 2002 time, workability, water retention and ing codes, and engineering require- sive strength, workability, and durability. durability. These components are pro- ments, should also be considered. Bond Strength: The mortar cement 4 portioned at the cement plant under Limitations: Mortar cements are specification is the only ASTM masonry controlled conditions to assure unifor- designed to be mixed with sand and material specification that includes mity of performance. water to produce a masonry mortar. The bond strength performance criteria. The Portland Cement Portland Association addition of hydrated lime to a mortar bond strength criteria were established Mortar Cement MORTAR AND MASONRY GROUT cement mortar at the job site is not to assure comparable bond strength required or recommended for conven- performance of the mortar cement to Table 1. Recommended Guide for tional unit masonry construction. non-air-entrained portland cement-lime Selection of Mortar Type Building Segment Type TECHNICAL DATA 1 Melander, J. M., and Ghosh, S. K., “Develop- Applicable Standards: Mortar ment of Specifications for Mortar Cement,” Exterior, above grade, Masonry: Esthetics, Engineering, and Economy, load-bearing N or S cements conform to ASTM C1329, the ASTM STP 1246, D. H. Taubert and J. T. non-load bearing N “Standard Specification for Mortar Conway, Eds., ASTM, West Conshohocken, PA, parapet wall N or S Cement.” Mortar cements are used to pp 88-99. Exterior, at or below 2 Borchelt, J. G., and Tann, J. A., “Bond Strength grade S or M produce ASTM C 270 Type O, Type N, Type S, and Type M mortars as outlined and Water Penetration of Low IRA Brick and Interior Mortar,” Proceedings of the Seventh North load-bearing N or S in either the property specification or American Masonry Conference, The Masonry non-load bearing N the proportion specification require- Society, Boulder, CO, pp. 206-216. Table 2. Physical Properties of Mortar Cements (ASTM C 1329) Mortar Cement Type N S M Fineness, residue on a 45-µm (No. 325) sieve, maximum % 24 24 24 Autoclave expansion, maximum, % 1.0 1.0 1.0 Time of Setting Initial Set, minimum, hr. 2 11⁄2 11⁄2 Final Set, maximum hr. 24 24 24 Compressive strength minimum, MPa (psi) 7 days 3.4 (500) 9.0 (1300) 12.4 (1800) 28 day 6.2 (900) 14.5 (2100) 20.0 (2900) Bond strength minimum, MPa (psi) 28 days 0.5 (70) 0.7 (100) 0.8 (115) Air content, volume, % Minimum 8 8 8 Maximum 17 15 15 Water retention, flow after suction as % of original flow Minimum 70 70 70 Table 3. Physical Properties of Mortar Cement Mortars (ASTM C 270) Compressive Strength Water Retention Air Content Mortar Type Minimum, MPa (psi) Minimum, % Maximum, % M 17.2 (2500) 75 12 S 12.4 (1800) 75 12 N 5.2 (750) 75 14* O 2.4 (350) 75 14* *When structural reinforcement is incorporated in (cement-lime or) mortar cement mortar, the maximum air content shall be 12%. Note: Physical properties listed in Table 2 and Table 3 are measured in accordance with prescribed laboratory test procedures. Conformance to compressive strength, bond strength, air content, and water retention requirements of Table 2 is determined using standard testing sand (ASTM C 778). Conformance to Table 3 requirements is established using a masonry sand (ASTM C144) that is intended to be used in construction. Mortar made using masonry sand typi- cally has lower compressive strength, lower air content, and higher water retention as compared to that achieved using standard sand. This fact is reflected in the differences between Table 2 (ASTM C 1329) and Table 3 (ASTM C 270) requirements for these properties. combinations of equivalent mortar type and jobs. Mortar cement mortars mixed ers contained in mortar cements con- designation1. As shown in Fig. 1, subse- according to the property requirements tribute to their workability and board quent research has confirmed that mor- of ASTM C 270 provide strengths that life. Fineness, time of setting, air con- tar cement mortars provide excellent exceed the values listed in Table 3. High tent, and water retention requirements bond strengths2. strength Type S and Type M mortar for mortar cements are specification The procedure utilized in determin- cements allow the specifier to accom- properties that relate to consistent per- ing conformance of mortar cement to modate special application require- formance with respect to workability. bond strength criteria seeks to elimi- ments related to load bearing masonry, The importance of workability is appar- nate, insofar as possible, the effects of masonry below grade level, and mason- ent when one considers that workman- workmanship, curing, and unit proper- ry for paving, without compromising the ship is a key element in achieving qual- ties on measured bond strength. There- advantages of simplified batching. ity masonry construction. fore, standard mixing, specimen fabri- Workability: Workability is the Durability: Expansion of mortars cation, curing, and testing procedures mason’s appraisal of the mortar’s ability due to unsound ingredients can cause are outlined, including the use of stan- to cling to head joints, slide smoothly off serious disintegration of masonry. dard testing units. It should be noted the trowel, and evenly support the Soundness of a cementitious material is that there are many factors that affect placement of units. Mortar of proper measured by the autoclave expansion the bond of mortar to unit in actual workability is soft but has good body; it test. This test produces reactions in any construction, including properties of spreads readily and extrudes from joints unsound ingredients and simulates a the unit and mortar, ambient condi- without smearing or dropping. Addition- long period of exposure for the cemen- tions, and the quality of workmanship ally, the masonry mortar needs to retain titious material. Conformance of mortar involved. these properties for a reasonable length cement to the autoclave expansion Compressive Strength: By simplify- of time at whatever ambient conditions limits of ASTM C 1329 assures that ing mortar materials batching at the job exist at the job site. That length of time there will be no significant expansion site, the use of mortar cement assures that the mortar retains its workability is of hardened mortar in a wall due to consistent strengths between batches often termed its board life. The plasticiz- unsoundness. 140 INSTALLATION Preparation: Mortar cement mortar materials mixed according to the pro- 120 portion specifications of ASTM C 270 should be accurately proportioned in 100 accordance with Table 4. Under the property requirements of 80 ASTM C 270, sand-to-cement propor- tions for the job mixed mortar are the same as those established by laboratory 60 Mortar Cement – S tests of the mortar. The ratio of sand to mortar cement is to be no less than 40 Portland Cement-Lime – S 21⁄4:1 and no more than 31⁄2:1. Machine mixing should be used Flexural Bond Strength – psi Mortar Cement – N whenever possible. First, with mixer 20 Portland Cement-Lime – N running, add most of the water and half the sand required. Next, add the mortar 0 cement and the balance of sand. After 1 4.3 one minute of continuous mixing, slow- Brick IRA – gm/30 in.2 min. ly add the rest of the water. Mixing Fig. 1 – Bond Strengths of Mortar Cement and Portland Cement-Lime should continue for at least 3 minutes. Mortars (Data from Ref. 2). Extending the mixing time up to 5 min- utes improves the mortar, resulting in better workability and water-retention. Mortar cements include air-entrain- must accommodate this fact. Important In mixing, as much water should be ing agents that provide advantages workmanship factors include achieving used as practical, without impairing the of improved freeze-thaw durability full head and bed joints, following workability of the mortar.