Mortar Kinds of Mortars ASTM C91 Specification for Masonry Cement ASTM C144 Specification for Aggregate for Masonry Mortar ASTM C270 Specification for Mortar for Unit Masonry ASTM C780 Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry ASTM C1329 Specification for Mortar Cement ______________ _________________ _______________ ASTM C1586 Standard Guide for Quality Assurance of Mortars __________: a • Proprietary product • Proprietary product combination of • Contains Portland similar to masonry cement and lime cement and fines, such cement as ground limestone • More stringent M a S o N w O r K • Additives such as air limitations on the strongest weakest entraining and water amount of air repellency agents. • Specified bond Typical uses: • Simple batching and strength to a standard Type __: Exterior below grade “fluffiness” due to unit. Type __: Exterior above grade and interior entrained air leads to • Recognized by codes Type __: Tuckpointing good productivity. to be equivalent to • Codes restrict use in high PCL mortar. seismic areas. Mortars and Grouts 1 Mortars and Grouts 2 Specifying Mortar Proportion Specifications • ____________ Specification Mortar Type Proportion by Volume (Cementious Materials) Aggregate Ratio • ________ for making mortar (measured in Portland Masonry or Mortar Cement Hydrated damp, loose • Proportion specification governs if neither is given Cement Lime or Lime MS N conditions) • ____________ Specification Putty 1 1 • Property specification is for ________ made mortar, not ____ mortar Portland- M 1 /4 2 /4 to 3 times Cement 1 1 the sum of the • Recipe developed based on lab mortar S 1 /4 - /2 • Recipe used for field mortar Lime N 1 1/ -11/ separate 2 4 volumes of 1 1 O 1 1 /4 -2/2 cementious Masonry M 1 1 materials Recommendation: Specify mix by or Mortar M 1 Cement proportions, even though it is default. S 1/2 1 S 1 N 1 O 1 Mortars and Grouts 3 Mortars and Grouts 4 Property Specifications Properties of Plastic Mortar Mortar Type Average compressive strength Aggregate Ratio (measured in damp, ________________: (most important property of plastic mortar) at 28 days (psi) loose conditions) 1. Spread easily with trowel into separations and crevices 1 Portland- M 2500 2 /4 to 3 times the sum of the separate 2. Support weight of masonry units when placed Cement S 1800 volumes of cementious materials 3. Adhere to vertical surfaces Lime N 750 4. Readily extrude from mortar joints when mason applies pressure to O 350 bring unit into alignment Masonry M 2500 5. Essential for good ______ with masonry units or Mortar S 1800 6. Measuring workability Cement N 750 A. ________ is best judge by observing O 350 response of mortar to trowel B. __________: percent increase in diameter Proportions are determined in the laboratory to meet these criteria, and of base of truncated cone when placed on then those proportions are used in the field. Field mortars do not have flow table and mechanically raised 1/2 in. to meet these requirements. Compressive testing of field mortar is and dropped 25 times in 15 seconds. simply for verifying consistency. Typical flow for construction mortars is in the range of 130 to 150%. Mortars and Grouts 5 Mortars and Grouts 6 Properties of Plastic Mortar, continued Properties of Hardened Mortar Water _________________: ______: (most important property) 1. Measure of ability of mortar under suction to retain its mixing water. 1. Strength: ___________ 2. Gives mason time to place and adjust unit without mortar stiffening. A. Increases with ______ content 3. Increased through higher lime content, or addition of sand fines B. Because of workability, Type _ within allowable gradation limits. mortar generally gives 4. Determined by performing flow test after some water has been maximum bond that can be removed by a specific amount of vacuum. achieved A. Water retentivity is ratio of initial flow to flow after suction, C. Bond can only be measured expressed as a percent. with units; thus not a property B. Typically, a water retentivity of 75% is required. of mortar alone 2. _____: amount of surface bonded A. Lack of extent leads to ____________ problems including moisture penetration, increased air flow, and increased sound transmission. 3. Increased ______ content increases bond ________ but reduces bond _________ due to loss of workability and increased shrinkage. 4. More serviceability problems with Type __ and Type __ mortars. Mortars and Grouts 7 Mortars and Grouts 8 Properties of Hardened Mortar, continued Properties of Hardened Mortar, continued ___________: _______________ strength: 1. Increase in air content increases durability. 1. Importance of compressive strength is _______________. 2. Oversanding, overtempering, or use of highly absorbent masonry 2. _____ strength and extent, ____________, and water ___________ units reduces durability are generally more important. 3. Increases with increase in _________ content _____________: maximum tensile strain at rupture 4. Decreases with increase in lime, sand, _______, or air content 1. Low strength, low moduli mortars exhibit greater plastic tensile 5. Measured using 2 inch cubes strains than high strength, high moduli mortars. 6. Mortar in practice is confined by units and in _______ state of stress 2. Mortars with _______________ than necessary should not be used. 7. Strength of mortar has only a small effect on prism, or wall strength A. Tests on clay tile prisms showed an order of magnitude increase in mortar compressive strength only doubled prism strength B. Empirical relationship suggest prism strength is proportional to fourth root of mortar compressive strength. 2 inch Mortar cube joint Mortars and Grouts 9 Mortars and Grouts 10 Bonus Slide, Not in Video Ingredients of Mortar ________________: Mortar Strength 1. Contributes to strength and durability of mortar 2. Provides early strength of mortar which is essential for speed of Type S Type M 16000 construction PSI 14000 3. Straight PC mortars are not used since they lack plasticity, have low 12000 water retentivity, and are harsh. 10000 4. PC mortars would give a strong wall, but the wall would be STRENGTH, 8000 6000 vulnerable to cracking and rain penetration. 4000 2000 ________: COMPRESSIVE 0 1. Provides workability, water retentivity, and elasticity Test 2.000 1.750 1.500 1.250 1.000 0.750 0.500 ⅜ As Built 2. Straight lime mortar would have low compressive strength and JOINT THICKNESS higher water retentivity Source: Reinforced Masonry Engineering Handbook, 7th ed., 3. Lime mortars would have a lower strength, but have a greater NCMA TEK 107 resistance to cracking and rain penetration. Mortars and Grouts 11 Mortars and Grouts 12 Ingredients of Mortar, cont Sand _______: 1. Natural or manufactured sand can be used 100 Compressive strength from 15 2. Void ratio of sand is about __ in __. Cementious materials will fill sets (3-4 cubes each) for Type 80 voids in sand; mortar mix is approximately volume of sand. N masonry cement mortar 3. Measured in damp loose condition. Dry sand is _____ times as 60 Average: 1930 psi dense as damp, loose sand. Minimum: 1240 psi 4. Well-graded sands reduce separation of materials in plastic mortar, 40 % Finer COV: 25% which improves workability. ASTM Limits A. Sands deficient in fines produce harsh mortars. 20 B. Sands with excess fines produce weak mortars; in extreme cases the mortar may not set up. 0 0.01 0.1 1 10 C. Sands that do not meet gradation requirements of C144 can be used provided resulting mortar can meet property specification. Grain Diameter (mm) Grain size distribution of natural river sands in Knoxville Mortars and Grouts 13 Mortars and Grouts 14 Ingredients of Mortar, cont Mortar Mixing _____________: 1. ___________________: generally not needed. Masonry cement Mix _____ minutes in mechanical batch mixer. typically has air entraining agents. Type A Portland cement is Workability is maintained by ___________. usually used, which has some air entraining additions. Slightly reduces compressive strength 2. ___________: require careful measuring and mixing Increases bond strength 3. _________________: Polymeric admixtures (Example is DRY BLOCK from W.R. Grace). One part is mixed throughout concrete Best results usually obtained if mortar is during manufacture of masonry unit. Other part is added to mortar maintained at ______ workable consistency. during mixing. Polymers cross link during curing to form resistance to water penetration. Discard mortar if it begins to stiffen or after 2.5 hours. New dorms across from aquatic center Mortars and Grouts 15 Mortars and Grouts 16 Placing Mortar and Units (3.3.B) Placing Mortar and Units (3.3.B) Additional Requirements: _____________: 1. Tool joints with round jointer to create a weather resistant surface. 1. Thickness: ⁄ ⁄ . 2. Do not disturb units after initially positioned; leads to reduced bond. 2. Starting course: at least ⁄ . and not more than: 3. Remove protrusions greater than 1/ in. that will interfere with grouting. 2 A. ⁄ . when masonry is ungrouted or partially grouted Hardwood Handle B. 1 ⁄ . when first course is solid grouted 3. Thicker bed joints decrease compressive strength Concave 4. Solid units: _______ bed joints Steel blade Slicker 5. Hollow units: ____________ bedding except in starting course, in columns and pilasters, and adjacent to grouted cells. “V” Grapevine _____________: 1. Solid units: ______ head joints 2. Hollow units: Width of _____________ thickness Sled-runner S-shaped jointers jointers Mortars and Grouts 17 Mortars and Grouts 18 Guide to ASTM Specs on Mortar Grout ASTM C 1586 Standard Guide for Quality Assurance of Mortars ASTM C476 Specification for Grout for Masonry Prior to Construction: ASTM C 270 ASTM C1019 Sampling and Testing Grout • Choose ____________ or __________ specifications • If property, make _____________ mortar specimens Grout is high-slump concrete (8-11 in.) made with small size aggregate. • Test mortar at a flow between 105% and 115% It serves three functions: • Representative of moisture content after mortar placed in wall 1.