342-13 masonry components %5bcompatibility mode%5d

7/27/2019 342-13 Masonry Components %5bCompatibility Mode%5d

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CVEN342Materials of Construction

Lecture 13

Masonry Components

Maryam S. Sakhaeifar, Ph.D.Assistant Professor

Zachry Department of Civil EngineeringPh: (979) 845-9961

E-mail: [email protected]

MasonryOne of oldest construction materials

Pyramids, Greek & Roman Ruins, Great

Wall of China

Components

Masonry units

Mortar

Composite Behavior

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Hagia Sophia

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Hagia Sophia


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Hagia Sophia

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Basilica Cistern

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Masonry Roof Structure

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Water Storage


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Masonry Units

Types

Manufacturing

Properties & Specifications

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Types of Masonry UnitsUse Wall

Facing Flooring

Type of construction Hollow (cored 25-60%) Solid (cored < 25%)

Location Interior

Exterior

Type of load Structural Non-load bearing

Stretcher Face

Header Face

Bed

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Types of Masonry Units

Focus on Clay Brick (Solid: Building, Facing, Paving; Hollow)

Masonry Units

Solid Hollow

StoneGlass

Block

Clay

Brick

Concrete

Brick

ModularCored < 25%

NonmodularCommon

Structural

Clay Tile

ConcreteMasonry

Unit

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Manufacturing Clay Brick

Raw Material

Clays (Surface, Fire/Deep, Shale/Hardened)

Silica, alumina, metallic oxides (appearance)

Clay propertiesImpact strength, durability, expansion, appearance

Plastic (shaped, molded)

Sufficient strength (maintain shape)

Fuse at elevated temperatures

Blend clays to obtain desired properties


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Manufacturing Clay Br ickWinning & Storage

Crushing, Sizing, & Blending

Forming / Molding

Tempering by adding water

Stiff-Mud (Extrusion) Process

Common


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DurabilityAbility to resist changes in environmental

conditions

Freeze-thaw is primary concern

Controlled by degree of fusion

Predictors of durability

Compressive strength Absorption

Specified limits on these properties & saturation

coefficient (F/T test may be used)

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Compressive Strength (ASTM C 67)

C = P / A

C = Compressive strength

P = Maximum load

A = Average of upper & lower bearing

surface areas

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Water Absorpt ion (ASTM C67)

Affects Durability (resistance to freezing)

24 hr submersion in cold water

5 hr submersion in boiling water% Absorption = 100 (Ws - Wd) / Wd

Ws = saturated specimen weight after

submersion

Wd = dry specimen weight


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Saturation Coefficient (C/B ratio)(ASTM C67)

Ratio of easily fillable void space to total

available void space

C/B = (Wc24 - Wd) / (Wb5 - Wd)

Wc24 = saturated specimen weight after 24 hr

submersion in cold water

Wb5 = saturated specimen weight after 5 hrsubmersion in boiling water

Wd = dry specimen weight

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Initial Rate of Absorption (IRA)(ASTM C67)

IRA = ((Wa - Wd) / An) * 30 in2

Wa = Specimen weight after partial

immersion (1/8) for 1 minute

Wd = Dry specimen weight

An = Net cross-sectional area of immersedsurface

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Initial Rate of Absorption (IRA)

(ASTM C67)

Affects bond strength

Only small effect on durability

Desired IRA/Suction < 30g/min per 30 in2

(Ideal IRA = 20 g/min per 30 in2)

Pre-wet if > 30 g/min per 30 in2

SSD condition

Excess water causes bleeding, floating

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Initial Rate of Absorption (IRA)

(ASTM C67)


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AestheticsColor

Chemical composition, firing temperature,

method of firing control

Iron has greatest effect

Flashing (reducing oxygen) used to change

color of surface

Surface Features Texture

Coatings

Glazes (may trap moisture)26

Specifications for Clay BrickType

Color

Texture

Size (Fig. 2.1)

Shape (Fig. 2.3)

Classification (ASTM)

Grade Type

Class Application

Dimensions (Fig. 2.2) Specified

Nominal = Specified +

Mortar Joint Thickness 1/2 or 3/8 = common

mortar joints

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Clay Brick Sizes

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Clay Brick Shapes


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Specifications for Clay Brick

ASTM Standards (Types)

C 62 (Building Brick)

C 216 (Facing Brick)

C 902 (Paving Brick)

C 652 (Hollow Brick)

Other

C 126 (Ceramic Glazed Structural Clay Facing Tile,Facing Brick, & Solid Masonry Units)

C 1088 (Thin Veneer Brick)

Other Standards for Other

Types of Masonry Units

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ASTM C 62 Building BrickSolid masonry units

Appearance not a consideration

Grades = f (environment)

SW - Severe weathering, may be frozen when

permeated with water

MW - Moderate weathering (TX) NW - No weathering, interior use

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ASTM C 62 Building Brick

Grade Requirements (Table 2.1)

Weathering

Index

Exposures Less

Than50

50

andgreater

In vertical surfaces:

In contact with earth

Not in contact with earth

In other than vertical surfaces:

In contact with earth

Not in contact with earth

MW

MW

SW

MW

SW

SW

SW

SW

weathering index = (average annual num ber of fr eezing cy cle days) *

(average annual wint er rainfall (inch es)) 32


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ASTM C 62 Building Brick

Physical Requirements (Table 2.2)

Min. CompressiveStrengthpsi (MPa)

Max. WaterAbsorption by5 hr boiling (%)

Max. SaturationCoefficient

Grade Avg of 5 Single Avg of 5 Single Avg of 5 SingleSW 3000

(20.7)2500(17.0)

17 20 0.78 0.80

MW 2500

(17.2)

2200

(15.2)

22 25 0.88 0.90

NW 1500(10.3)

1250(8.6)

No limit No limit No limit No limit

Saturation Coefficient = ratio of absorption by 24 hr submersion in cold water

to absorption after 5 hr submersion in boiling water34

ASTM C 216 Facing Brick Solid Masonry Units

Appearance is a consideration Limits chips, Cracks Tolerances on Dimensions, Distortions

Grades (same requiremnts as C 62)

SW - Severe Weathering, May be frozen when

permeated with water

MW - Moderate Weathering

Types FBS - Standard, General exposed use FBX - Select, Tighter Control on size

FBA - Architectural, Non-uniform, Used look

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ASTM C 902 Paving Brick

Only for pedestrian & light vehicular traffic

Patios / plazas, walkways, floors, driveways

Classes

SX - severe exposure, may be frozen whensaturated with water

MX - moderate exposure, resistance to freezing

not a factor

NX - no exterior exposure, interior use with

surface coating

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ASTM C 902 Paving Brick

TypesType I - Extensive Abrasion

Driveways, Building Entrances

Type II - Intermediate Traffic Store / Restaurant Floors, Exterior Walkways

Type III - Low Traffic Floor / Patios in Homes

ApplicationsPS - Standard, with Mortar Joints

PX - Select, without Mortar Joints, Tighter Controlon Size

PA - Architectural, Non-uniform, Used Look


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ASTM C 902 Paving BrickPhysical Requirements (Table 2.3)

Min. CompressiveStrengthpsi (MPa)

Max. WaterAbsorption by24 hr soaking

(%)Max. Saturation

Coefficient

Class Avg of 5 Single Avg of 5 Single Avg of 5 SingleSX 8000

(55.2)7000(48.3)

8 11 0.78 0.80

MX 3000(20.7)

2500(17.2)

14 17 No limit No limit

NX 3000(20.7)

2500(17.2)

No limit No limit No limit No limit

Saturation Coefficient = ratio of absorption by 24 hr submersion in cold water

to absorption after 5 hr submersion in boiling water 38

Concrete Paver Units

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ASTM C 652 Hollow Brick

Hollow Masonry Units

Grades (same requirements as C 62) SW - severe weathering, may be frozen when permeated with

water

MW - moderate weathering

Classes H40V - 25-40% voids in cross section parallel to bearing surface

H60V - 40-60% voids in cross section

Types HBS - standard, general exposed use

HBX - select, tighter control on size

HBA - architectural, non-uniform, used look

HBB - appearance not a consideration

Mortar

Definitions

Differences w/ other cementitious mixtures

Classes

Components

Types

Properties


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Mortar

Cementitious Materials

Lime

Portland Cement

Sand

Water

Used with individual

masonry units

Bonding

Bedding / Seating

Leveling

Sealing Irregularities

Providing Strength

Providing Aesthetic Qualities

Mortar

Weak link in masonry

construction

Thin layer stronger

(compression) than thick

layer

Lime added

Workability

Adhesive properties

Extensibility

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 fC - less

in non-absorbent molds

Match with masonry fC

Differences w/ Other Cementi tious

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


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Differences w/ Other Cementit iousMixtures

Structural Performance

PCC is structural material, resists mainly compressivestresses

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 important46

ComponentsPortland 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

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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

342-13 masonry components %5bcompatibility mode%5d

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