Exam 2 Codes and Specs Lsn 17-

Definition of Masonry

Masonry units and mortar

Masonry Units

Brick or Concrete Masonry

List all Seven Wall Classifications for Masonry

Exterior Walls, Interior Walls, Load Bearing Walls, Non-Load Bearing Walls, Solid Walls, Hollow Walls, and Framed Walls

Definition of Load Bearing Walls

A wall that carries loads from other members

Definition of Exterior Walls

Walls that are exposed to the environment

Definition of Solid Walls

Walls that have no empty cavity/cores/cells

Definition of Hollow Walls

Walls with empty cores/cells in units

Definition of Framed Walls

Walls that are made of timber or metal

Definition of a Wythe

Thickness of masonry unit in a continuous vertical section (Thickness of one unit)

Definition of Bonded Wall

When the faces of the units are bonded together

Definition of a Cavity Wall

The open cavity between the Wythe’s

Definition of a Veneered Wall

Non-structural Wall

What is the inequality of a Hollow Unit (Anet and A gross)?

Anet < 0.75 Agross

What is the inequality of a Solid Unit (Anet and A gross)?

Anet >/equal to 0.75 A gross

What areas do we use for Anet/Agross?

The area on the plane parallel to the bearing surface

Equation for Net Area?

Agross x Net Volume/ Gross Volume

What are the five materials in Clay Bricks?

Silica and Alumina, Iron, Manganese, Sulfur, and Phosphates

What does Silica and Alumina do in Clay Bricks?

It absorbs moisture, makes clay plastic, and melts away when it is burned.

What does Iron do in Clay Bricks?

It improves the hardness and strength of the brick

What are the four steps in manufacturing bricks?

Grind the clay, mix with water, shape/form and texture, Dry (40-150 Celsius), Fire (900-1000 Celsius).

What are the different Clay types?

Surface clay, shale, fire clay, and ideal clay.

Surface Clay?

Found near surface, unconsolidated, high oxide (10-25%)

Shale?

Deeper in soil, compacted form

Fire Clay?

Deeper still, more uniform, low oxide, withstand higher temperatures

Ideal Clay?

Approximately 30% sand and silt

What are the three grades for bricks?

Sever Weather, Moderate Weather, and Negligible Weather

What are the grades of a brick based off of?

The strength and durability (absorption/saturation)

What is the rule of thumb when choosing grades of bricks?

Choose the grade of brick above what is required

When should we use negligible weather bricks?

Interior only, no freezing (interior use only)

What is a building/common brick?

A structural, strong and durable brick

What is a facing brick?

Used where appearance is important

What are the different types of facing bricks?

Type Facing Brick Standard, Type Facing Brick Extra, Type Facing Brick Architecture

Type Facing Brick Standard?

General use, exposed construction (SW, MW)

Type Facing Brick Extra?

When precise tolerances are needed

Type Facing Brick Architecture?

Non-uniformity, architectural effects

What are the actual dimensions of a brick?

The direct dimensions of the brick itself

What is the nominal dimension of a brick?

Actual Dimension + 1 mortar joint thickness

What is the Nominal Height/Length?

The actual height/length with two joint heights added

What are the tolerances allowed due to shrinkage in nominal dimensions?

3/32 in to 3/8 in

What is a bed joint?

The joint that runs along the length of the masonry untit

What is the head joint?

The joint that runs along the height of the masonry unit

What is the density range of clay brick?

100 pcf - 125 pcf

What does the property absorption effect in clay bricks?

Affects durability, affects bond strength by taking water from surrounding mortar

What is the ASTM absorption limit for Severe Weather grade bricks?

17%

What is the ASTM absorption limit for Moderate Weather grade bricks?

22%

What is the ideal absorption percentage for clay bricks?

<10% (4-10% typical)

What is Initial Rate of Absorption (ASTM C67)?

It measures the capillary action of removing water from mortar affecting both curing and bond strength. The higher the value the weaker the joint.

What is a good initial rate of absorption for clay bricks?

< 20 g/min per 30 in²

What does the strength of a clay unit depend on?

Composition of clay, method of manufacturing, and degree of burning

How do we calculate Compressive Strength?

Fc = Failure Load/ Anet (bearing area), if Anet > .75Agross use A gross

What are the minimum compressive strengths for SW, MW, and NW brick grades?

SW: 2500 psi, NW: 2200 psi, NW: 1250 psi

What is the modulus of rupture equation?

MOR = (1.5PL)/[(l + 1)t²]

What is the typical flexural strength of a clay brick?

500 psi - 3800 psi

How do we calculate Tensile Strength in a clay brick?

Ft = (0.3 to 0.4) *MOR

How do we calculate shear strength in clay bricks?

Shear Strength = (0.35 to 0.45) * Compressive Strength

What is the range for Modulus of Elasticity in Clay Bricks?

1.5 E6 psi to 5 E6 psi

What is the range of thermal expansion for clay bricks?

0.3 to 0.4 inches per 100 ft for t1-t2 = 100 F

What are other features of clay bricks?

Good fire resistance, non-combustible, moderate insulating properties

What are common names for concrete masonry units?

Cinder blocks, hollow blocks, concrete blocks, solid or hollow units

What are the two types of concrete units?

Concrete building brick and Load Bearing Concrete Masonry Units

What are properties of concrete building bricks?

Solid units, similar in size to brick, high compressive strength, Normal and light weight aggregate used

What are properties of load bearing concrete masonry units?

Solid or hollow, lower compressive strength that building brick

What type of mix do concrete masonry units have?

Dry mix with little water in the mix

What are the three types of weights for concrete masonry units?

Normal, medium, and light weight

What are the properties of Normal Weight Concrete Units?

Unit Weight > 125 pcf and it consists of well graded sand, gravel, and crushed stone

What are the properties of Medium Weight Concrete Units?

Unit Weight is between 105 pcf and 125 pcf

What are the properties of Light Weight Concrete Units?

Unit weight is between 85 pcf and 105 pcf, light weight aggregate used, and typically light weight aggregate absorbs more moisture

What types of concretes are used in concrete units?

Type I (General Purpose) and Type III (Faster Strength)

What properties are changed in air entrained IA and IIIA cement concrete units?

Improvements in workability, molding, resistance to freeze-thaw, and decrease in compressive strength

What are the types of concrete masonry unit?

Type I (moisture control) and Type II (non-moisture controlled)

What are the Strength/Stiffness properties of Concrete Masonry Units?

Compressive Strength: 1900 psi - 6000 psi

Tensile Strength: 250 psi - 500 psi

Elastic Modulus: 1.4 E6 psi to 4.5 E6 psi

What are the shrinkage properties of Concrete Masonry Units?

Linear Shrinkage: Change in length of unit form wet to dry conditions

Limit: 0.065%

Higher moisture content meaning that there is higher shrinkage if the units are allowed to dry

The larger the size the greater the shrinkage

What are the nominal dimensions of concrete units?

Widths: 4, 6, 8, 10, 12 inches

Lengths: 12, 16, 24 inches

Heights: 4 or 8 inches

(True dimensions are 3/8 inches less)

What are the Grades of Concrete Masonry Units?

Grade N: Type I and II, high strength and moisture resistance, good for freeze conditions, minimum compressive strength is 3000 psi

Grade S: Type I and II, general use, moderate moisture resistance, and minimum compressive strength is 2000 psi

What are some descriptions of Mortar?

Bonds masonry together, transfers stress uniformly over surface, seats and levels the units, mixture of cement+lime+sand+water

What are some descriptions of grout?

High slump concrete, fills cores of masonry units, mixture of cement+fine gravel+sand+water

What does portland cement type I or II do when added to mortar?

Provides early hardening, compressive strength, and durability of mortar

What makes up Lime Mortar?

Lime+Sand

What are some descriptions of Portland-Cement Lime Mortar?

Consists of Portland Cement, Lime, Sand, and HAS HIGH TENSILE BOND STRENGTH

What are some descriptions of Cement Mortar?

It consists of portland cement, pozzolan/slag cement, plasticizers, air entrainers, water retention admixtures, ground limestone (filler), GOOD WORKABILITY (“FLUFFY”), LOWER TENSILE BOND STRENGTH, NOT PERMITED IN EARTHQUAKE ZONES

What is a chemical product of when synthesizing quick lime?

CO2, Green House Gases

What is a product of synthesizing hydrated lime?

Heat

What effects does mix proportions of cement have on mortar?

Early hardening, compressive strength, and durability

What effects does mix proportions of aggregates have on mortar?

Want finer aggregate, approx. 10% finer than 75 micrometers, coarser sand lowers workability, fine sand produces higher compressive strength than coarse sand, fine sand decreases water retention, fineness contributes to plasticity and workability, finally ASTM has gradation requirements for mortar

What effects does mix proportions of water have on mortar?

Decrease in water reduces shrinkage and improves water tightness, increase in water improves workability and plasticity

What effects does mix proportions of lime have on mortar?

It improves workability of mortar and plasticity, retains and holds moisture, resists suction from masonry unit, improves bond strength, makes less permeability, and lowers shrinkage

What are the most important properties when considering mix proportions of mortar?

Workability, water retention, bond strength, compressive strength, and durability

What are some characteristics of Hydraulic Lime?

It requires water to transform into a solid, gains strength through hydration, and contains alumina and silica

What are some characteristics of Non-Hydraulic Lime?

It does not require water to transform into a solid, takes in CO2 and gains strength, and is made of pure limestone

What is the compressive strength range of Lime Mortar?

100 psi - 400 psi at 1 year

What is the tensile strength range of Lime Mortar?

40 psi - 150 psi at 1 year

What type of construction is Lime Mortar NOT recommended for?

Permanent Construction

What Acronym can we use to remember Mortar Grades?

MASONWORK (skipping each second letter MSNOK)

What characteristics does grade M mortar have?

High Compressive strength and bond strength, good for exposure to severe weather or masonry built below ground, used for load bearing and non-loadbearing wall, and it is Used for exterior walls and parts of wall below ground

What characteristics does grade S mortar have?

Moderate compressive strength and bond strength, used for load/non-load bearing walls, and is used for exterior walls and parts of wall below ground

What characteristics does grade N mortar have?

Low compressive strength and bond strength, and is used for load/non-load bearing walls

What characteristics does grade O mortar have?

Very low compressive strength and bond strength

What characteristics does grade K mortar have?

It is no longer used

Are the grades in MASONWORK organized in ascending order for Compressive/Tensile Strength, or descending order?

Descending, meaning Grade M is highest in Compressive and Tensile strength, whereas O is the lowest in both

Are the grades in MASONWORK organized in ascending order for % Air, or descending order?

Descending, MS have %Air = 12%, NOK have %Air = 14%