+ All Categories
Home > Documents > Masonry Cement and Mortar

Masonry Cement and Mortar

Date post: 03-Apr-2018
Category:
Upload: lokuliyanan
View: 229 times
Download: 0 times
Share this document with a friend
31
1 Lecture #18 Masonry Cement and Mortar  
Transcript

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 1/31

1

Lecture #18

Masonry Cement and Mortar 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 2/31

MORTAR

• binder = mortar 

• Masonry = mortar + masonry units

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 3/31

MORTAR

• definitions

• differences w/ other cementitious

mixtures

• classes

• components

• types

• properties

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 4/31

MORTAR

• cementitious

materials

 – lime – portland cement

• sand

• water 

• used with individual

masonry units

 – bonding – bedding / seating

 – leveling

 – sealing irregularities

 – providing strength

 – providing aesthetic qualities

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 5/31

MORTAR

• weak link in masonry

construction

• thin layer stronger 

(compression) than thick

layer 

• lime added

 – workability

 – adhesive properties – extensibility

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 6/31

GROUT• cement

• fine and coarseaggregate

• sand

• water 

• high slump

• no segregation

• used to bond two masonry

wythes together (walls one unitthick)

 – filling cores and voids

 – binding reinforcing steel and

wythes

 – providing load carrying capability

•  ASTM C476

• fine and coarse grouts f’C - lessin non-absorbent molds

 – match with masonry f’C

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 7/31

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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 8/31

8

Differences w/ other cementitious

mixtures• structural performance

 – PCC is structural material, resists mainly compressive

stresses

 – mortar, grout are binders, develop strong & durablebond 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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 9/31

9

Classes• lime mortar 

 – lime, sand, water 

 – slow strength gain

 – calcium carbonate

formation – seldom used in

permanent construction

• cement/cement-lime mortar 

 – cement, lime, sand, water 

 – most common

• masonry cement mortar  – proprietary ingredients

 – workable

 – low bond strength, not

durable - most commonly

used but least desirable 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 10/31

10

Components• portland cement

 – 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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 11/31

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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 12/31

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 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 13/31

13

Components• aggregates

 – natural or manufactured – gradation (ASTM C144)

Amounts Finer than Each Laboratory sieve (Square Openings),

Weight %

Fine Aggregate Coarse Aggregate

Mortar or Grout

Sieve size

Grout Natural Manufactured

Size No. 8 Size No. 89

½ -in (12.5-mm)

3/8-in (9.5-mm)

 No. 4 (4.75-mm) No. 8 (2.36-mm)

 No. 16 (1.18-mm)

 No. 30 (600-m)

 No. 50 (300-m)

 No. 100 (150-m)

 No. 200 75- m

100

95 to 10080 to 100

50 to 85

25 to 60

10 to 30

2 to 10

10095 to 100

70 to 100

40 to 75

10 to 35

2 to 15

10095 to 100

70 to 100

40 to 75

20 to 40

10 to 25

0 to 10

100

85 to 100

10 to 300 to 10

0 to 5…

100

90 to 100

20 to 555 to 30

0 to 10

0 to 5…

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 14/31

14

Components

• water  – clean

 – potable

 – free of deleterious

materials

• acids

• alkalies

• organic materials

• admixtures – color 

 – workability

 – reduced water 

penetration

 – accelerated curing

 – use w/ caution – air-entraining

 – chlorides

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 15/31

15

Types (MASONWORK)•  ASTM C270

 – 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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 16/31

16

Types (MASONWORK)

• Type S (structural masonry, reinforced brick) – high strength

 – reinforced masonry

 – areas subject to high wind

• Type N (normal, common)

 – high strength

 – general use

 – below grade OR in contact w/ ground

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 17/31

17

Types (MASONWORK)

• Type O (interior) – low strength

 – non-bearing applications

 – not subject to severe weathering

• Type K (restoration)

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 18/31

18

Types (MASONWORK)• Proportion Specifications

Proportion by Volume (Cementitious Materials)

Masonry CementMortar Type

Portland

Cement or Blended

CementM S N

Hydrated Limeor Lime Putty

Aggregate Ratio

(Measured inDamp, Loose

Condition)

Cement-Lime M 1… … …

¼

S 1 … … … Over ¼ to ½

 N 1 … … … Over ½ to 1 ¼

O 1 … … … Over 1¼ to 2 ½

Masonry Cement M 1 … … 1 …

M … 1 … … …

S ½ … … 1 …

S … … 1 … …

 N … … … 1 …

O… … …

1…

 Not less than

2¼ and notmore than 3

times the sum

of the separate

volumes of Cementitious

materials.

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 19/31

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)

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 20/31

20

Types (MASONWORK)• Property Specificationsa 

Mortar Type

Average

Compressive

Strength at 28 Days,

Min. psi (MPa)

Water Retention,

min, %

Air Content,

max, %

Aggregate Ratio

(Measured in

Damp, Loose

Condition)

Cement-Lime M 2500 (17.2) 75 12

S 1800 (12.4) 75 12 N 750 (5.2) 75 14

 b

O 350 (2.4) 75 14 b

Masonry Cement M 2500 (17.2) 75 …

c

S 1800 (12.4) 75 …

c

 N 750 (5.2) 75 …

c

O 350 (2.4) 75…

c

 Not less than 2¼

and not more

than 3½ times the

sum of the

separate volumes

of cementitious

materials

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%. 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 21/31

21

Selecting Mortar Types• considerations

 – structural

requirements

 – exposure

 – wall type

 – workability

• no single type for all

purposes

• DO NOT change mortar 

types within samestructure

 – uneconomical

• NEVER use mortar 

stronger in compression

than required

 – shrinkage, debonding

 – uneconomical

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 22/31

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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 23/31

23

Properties• plastic 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 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 24/31

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

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 25/31

25

Flow (ASTM C109)• cone formed on flow table

• raised & dropped 25 times in 15 seconds

• flow = ratio of increase in diameter 

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 26/31

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 27/31

27

Bond Strength• most important physical property

• difficult to measure directly, simulate construction

Bond Strength

Max Bond

• cement: lime

1:1 to 1:1/4•Type S mortar 

Suction (IRA)   

 Air Content    

Elapsed Time  

 

Mortar Flow    

Brick Texture rough  Retempering  

Pressure    

Movement after set  

Water Retentivity

  

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 28/31

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 29/31

29

Other Hardened Properties

• durability

 – not significant if 

properly prepared

 – no air-entraining

components

• extensibility

 – max et at rupture

 – elongation beforecracking

 – lime contributes

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 30/31

30

Other Hardened Properties• compressive strength

 – f (cement content, w/c)

 – cubes (ASTM C109)

 – cylinders, briquettes

Proportion f’c

 

Cement    

Lime    

Water     

Flow    

7/28/2019 Masonry Cement and Mortar

http://slidepdf.com/reader/full/masonry-cement-and-mortar 31/31

31

Other Properties

• color  – colored aggregates - PREFERRED

 – colored pigment


Recommended