Portland cement acts as bonding agent lime imparts

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Unformatted text preview: ent, lime imparts smoothness and workability, sand provides the bulk around which lime sets, and water provides workability to set bricks properly. Setting of hydrated lime with absorption of CO2 from air makes the mortar strong hydrated from Masonry mortar (has various trade names): Contains one or more of the following, viz. , Portland cement, Portland-pozzolan cement, natural cement, slag cement, Portland-blast furnace slag cement, hydraulic lime, and in addition usually contains hydrated lime, limestone, chalk, calcareous shell, talc, slag and/or clay and/or Mortar Functions Provides for full bearing Seals between masonry units Adheres / bonds masonry units Aesthetics 17 Joint Color that “Blends” w/ Brick Color 18 19 Mortar Pre-packaged Color range Testing / Specifications Curing “Shelf” life 20 9.3 USES AND TYPES OF MASONRY MORTAR (Cont’d) (Cont’d) 9.3 In order to achieve workability, masonry mortars contain air-entraining In admixtures that produce high air content in mortar; this reduces the bond strength of masonry mortar - For these reasons, for masonry work that requires high strength and low permeability, only conventional cement-lime mortar should be used - Lime mortar cures by drying and absorption of CO2 from air to form used CaCO3, whereas Portland cement mortar cures by hydration that produces a CaCO whereas dense, strong, and crystalline structure that binds the sand particles together - To prevent premature drying masonry units should be wetted before laying them in course. course. Mortar types : (a) M-type - High strength mortar - 2,500 psi - Used for M-type buildings subjected to large lateral loads, and below grade (earth level) masonry; (b) S-type - Medium high strength mortar - 1600 psi - Used for masonry S-type structures needing high flexural bond strength and normal compressive loads: (c ) N-type - Medium strength mortar - 750 psi - for general use above grade; and (d) N-type O-type - Medium low strength mortar; 350 psi - Used for non-load-bearing walls O-type and partition 9.3 USES AND TYPES OF MASONRY MORTAR (Cont’d) (Cont...
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This document was uploaded on 03/06/2014 for the course ENG 3731 at Memorial University.

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