Presentation is loading. Please wait.

Presentation is loading. Please wait.

Masonry Cement and Mortar

Similar presentations

Presentation on theme: "Masonry Cement and Mortar"— Presentation transcript:

1 Masonry Cement and Mortar
Lecture #18 Masonry Cement and Mortar

2 MORTAR binder = mortar Masonry = mortar + masonry units

3 MORTAR definitions differences w/ other cementitious mixtures classes
components types properties

4 MORTAR cementitious materials sand water
lime portland cement sand water used with individual masonry units bonding bedding / seating leveling sealing irregularities providing strength providing aesthetic qualities

5 MORTAR lime added weak link in masonry construction
workability adhesive properties extensibility weak link in masonry construction thin layer stronger (compression) than thick layer

6 GROUT cement fine and coarse aggregate sand water high slump
no segregation used to bond two masonry wythes together (walls one unit thick) filling cores and voids binding reinforcing steel and wythes providing load carrying capability ASTM C476 fine and coarse grouts f’C - less in non-absorbent molds match with masonry f’C

7 Differences w/ other cementitious mixtures
component materials mortar cement, lime, water, fine aggregate grout cement, water, fine aggregate, small-sized coarse aggregate portland cement concrete cement, water, fine aggregate, coarse aggregate proportions

8 Differences w/ other cementitious mixtures
structural performance PCC is structural material, resists mainly compressive stresses mortar, grout are binders, develop strong & durable bond w/ masonry unit workability & placement methods PCC placed in non-absorbent forms, minimum water, w/c ratio very important to performance mortar, grout placed in absorptive forms, much more water, w/c ratio less important

9 Classes cement/cement-lime mortar lime mortar masonry cement mortar
cement, lime, sand, water most common masonry cement mortar proprietary ingredients workable low bond strength, not durable - most commonly used but least desirable lime mortar lime, sand, water slow strength gain calcium carbonate formation seldom used in permanent construction

10 Components portland cement sand lime water admixtures durability
high early strength high compressive strength bond strength sand filler strength lime workability water retentivity elasticity bond strength extensibility water flow required for hydration admixtures

11 Components portland cement
Type I - general use when special properties not required Type II - when moderate sulfate resistance or moderate heat of hydration required Type III - when high early strength required Air entrained portland cements tend to reduce bond strengths

12 Components hydrated lime [Ca(OH)2]
chalk or limestone (CaCO3) burned at 900 0C in kiln to produce quicklime (CaO) water added to quicklime Types (ASTM C207) N - normal, unhydrated oxides & plasticity not controlled S - special, commonly used NA - normal air-entraining, not recommended SA - special air-entraining, not recommended

13 Components aggregates natural or manufactured gradation (ASTM C144)

14 Components water admixtures clean potable
free of deleterious materials acids alkalies organic materials admixtures color workability reduced water penetration accelerated curing use w/ caution air-entraining chlorides

15 Types (MASONWORK) ASTM C270 Type M (paving brick)
proportion specifications - RECOMMENDED property specifications established with laboratory testing, trial & error same letter designations, but Type N (proportion) = Type N (property) (proportion - higher compressive strength) Type M (paving brick) high strength general use below grade OR in contact w/ ground

16 Types (MASONWORK) Type S (structural masonry, reinforced brick)
high strength reinforced masonry areas subject to high wind Type N (normal, common) general use below grade OR in contact w/ ground

17 Types (MASONWORK) Type O (interior) Type K (restoration) low strength
non-bearing applications not subject to severe weathering Type K (restoration)

18 Types (MASONWORK) Proportion Specifications

19 Determine quantities and absolute volumes for an N Type Mortar
Vsand = 1.0 ft3 Vlime= 0.5 to 1.25 Vc Vsand=2.25 to 3 (Vc+Vl) 1 ft3 of damp loose sand will yield 1 ft3 of mortar. (due to bulking of wet sand)

20 Types (MASONWORK) Property Specificationsa
a Laboratory prepared mortar only b When structural reinforcement is incorporated in cement-lime mortar, the maximum air content shall be 12% c When structural reinforcement is incorporated in masonry cement mortar, the maximum air content shall be 18%.

21 Selecting Mortar Types
considerations structural requirements exposure wall type workability no single type for all purposes DO NOT change mortar types within same structure uneconomical NEVER use mortar stronger in compression than required shrinkage, debonding

22 Laboratory vs. Field Mortar
CANNOT COMPARE field mortar more water required (lost in evaporation or to masonry unit) laboratory mortar less water, lower initial flow different curing conditions

23 Properties plastic properties hardened properties other properties
influence hardened properties workability initial flow flow after suction water retentivity hardened properties determine performance bond strength durability extensibilty compressive strength other properties color

24 Workability easily spread adhere to vertical surface
difficult to measure directly no standard test or quantitative measure indicators include flow, water retentivity, resistance to segregation affected by properties of components

25 Flow (ASTM C109) cone formed on flow table
raised & dropped 25 times in 15 seconds flow = ratio of increase in diameter

26 Water Retentivity (ASTM C91)
ability to resist loss of water to absorbent masonry unit flow after suction (vacuum for 1 min)/ initial flow low retentivity will bleed moisture unless brick has high suction (IRA) high retentivity will create dry surface low bond strength for low or high retentivity paired with average masonry unit

27 Bond Strength most important physical property
difficult to measure directly, simulate construction Bond Strength Suction (IRA)   Air Content   Elapsed Time   Mortar Flow   Brick Texture rough  Retempering  Pressure   Movement after set  Water Retentivity   Max Bond cement: lime 1:1 to 1:1/4 Type S mortar

28 Bond Strength

29 Other Hardened Properties
durability not significant if properly prepared no air-entraining components extensibility max et at rupture elongation before cracking lime contributes

30 Other Hardened Properties
compressive strength f (cement content, w/c) cubes (ASTM C109) cylinders, briquettes Proportion f’c Cement   Lime   Water   Flow  

31 Other Properties color colored aggregates - PREFERRED colored pigment

Download ppt "Masonry Cement and Mortar"

Similar presentations

Ads by Google