Engineered panel composed of several wood veneer sheets placed at right angles to one another or veneer sheets placed across a lumber, mineral, or oriented strand board core. Bonded by high pressure and waterproof or resistant adhesive.
Uses for plywood
Construction- wherever strength is important as it is resistant to checking and spliting
Decorative- Wall paneling, Cabinet work, and furniture.
Made mostly from softwood veneers. Rarely hardwood veneers.
Center veneers are usually of lower quality or different species. Exterior veneers are higher quality.
Rotary Cut Veneer
Tree is debarked and cut into log-shaped blocks and peeled by knife in long peels that are 1/10 in. to 3/16 in. thick.
Veneers used for decorative plywood are sometimes sliced. Very small amount of softwood plywood is manufactured of sliced veneer.
PS 1 Product Standard 1
Construction plywood should comply with Product Standard 1. This is the grading rules for construction plywood and the accepted bond, panel construction, dimensional tolerance, and workmanship requirements. Also includes the procedures for testing, grading, labeling, and identifying plywood.
American Plywood Association maintains a quality control program to ensure that plywood carrying an official grade trademark conforms with PS1.
Exposure types of Plywood
1. Interior type
-Plywood Bonded with intermediate glue
-Plywood bonded with exterior glue
2. Exterior type
Exterior Type (waterproof) Plywood
Veneers are grade C or better. Designed to retain glue bond under one of 3 different levels of exposure
2. Exposure 1- Maybe exposed for long time to water but eventually protected. Same exterior type glue used.
3. Exposure 2 - Used where exposure is limited before being protected.
Interior Type Plywood
D grade veneers or better.
1. Moisture-resistant- Intended for interior applications and temporary exposure to elements
2. Plywood Bonded w/ intermediate glue- Has lower moisture resistance than exterior glue but is resistant of bacteria, mold and moisture. Can be used where humidity and water leaks may exist.
3. Plywood Bonded w/ exterior glue- Intended for use where max performance in protection against moisture exposure from long construction delays or other conditions of similar severity.
Designation is based off of the species group and the quality of the veneer used on the face and back. Grades range from N(highest) through A ,B ,C ,and D(lowest). Veneers can be repaired to raise grade quality by filling in voids and replacing knots and pitch pockets.
N grade Veneer Plywood
Is very special and rare. Is free of all major defects and few well matched repairs. Is all heartwood or sapwood.
A grade Veneer Plywood
Smooth paint grade with few near repairs. Specified for under high-quality work.
B grade Veneer Plywood
Solid surface except for specified minor characteristics. May have number of neat repairs. Ok for form work for concrete.
C grade Veneer Plywood
Comes in C plugged grade and C grade.
C plugged is intended for underlayment for floors and combination subfloor underlayment.
C grade is the lowest quality of veneer allowed for exterior type panels. Permits average size knots and splits.
D grade Veneer Plywood
Lowest quality of veneers. Permits most knots, splits and other defects.
Panels are assigned to letters ex. A-B. The first letter is for the front face and the second letter is for the back face. The panels in between are D or better on interior panels and C or better on exterior panels.
Performance Panels or Structural use panels
Panels designed for use where tension, compression, shear, cross-panel flexural properties, and nail bearing may be significant. In this group are panels designed for use as floor, wall or roof sheathing; for subflooring; underlayment, or both; for siding; for construction of stress-skin panels, box beams, and other structural elements; and for other structural uses.
Rating assigned to Performance panels that determines the support spacing required for each.
When a single number is given it is the required maximum spacing of the supports in inches when used as a flooring material.
When two numbers are given separated by a slash is given, the first number represents max spacing in inches when the panel is used as a roofing and the second for flooring.
High-grade panels of exterior plywood to which cellulose-fiber sheets with prescribed amounts of resin have been bonded to one or both faces. Three types which are High Density Overlaid, Medium Density overlaid and specialty overlaid.
High Density Overlaid (HDO)
Face veneers of A-A or B-B. Inner plies are C Plugged veneers. Has hard, smooth, chemically resistant, durable surface that requires no further finishing by paint or varnish. Can be painted, suitable for concrete framework for architectural finish, highway signs
Medium Density Overlay (MDO)
Face veneer are B-B and inner veneers are C veneers. Intended for high quality paint finishes and is made so grain will disappear when painted over.
Panels that don't meet the HDO and MDO qualities but meet glue bond requirements for overlaid plywood. Panels must be of exterior type.
Textured Siding panels
Used for exterior siding, gable ends, and fencing and for forms for special effects in concrete.
Mostly made from hardwood species. Some softwoods like knotty pine, California redwood and western red cedar.
Concrete Form Panels
Not less than B grade veneers. Interior not less than C grade veneers. Usually sanded and grouped into Class I or Class II.
most readily available in 4ft x 8ft. Panels can be jointed together to make larger pieces. Can be 1/16 in. smaller but no larger in horizontal dimension. Must have at least 3 layers in board.
Vulnerable part of plywood
is the edges where the glue is susceptible to water.
It is strongest along the face grain than against it.
Changes in Plywood (warp, Hygroscopic expansion, checking, and fire and decay resistance)
All are affect when moisture is in contact with plywood.
Made mostly of Hardwood and is determined by PS1 and Hardwood Plywood and Veneer Association (HPVA) standard HP-1. Interior layers of plywood are softwood but face veneers are always hardwood veneers. Used for wall panelings, cabinets, skin faces for doors, and as face veneer for block flooring.
Species of Hardwood plywood
240 commercial qualities of hardwood plywood. 50 are widely used.
Parts of tree used in Hardwood plywood
Mostly comes from straight part of tree but valuable parts comes from crotch, burl, or stump.
Log is mounted on a lathe and then turned against a blade. Figure has bold variegated ripple.
Flat slicing veneer
A varied wavy figure. Produced by a half long or flitch is mounted with the heart side flat against the guide plate of a slicer, and the slicing is done parallel to a like through the center of the log.
Had series of stripes in wood that are straight in some and varied in others. Produced by taking a quarter log and mounting it on a guide plate so that the growth rings of the log strike the knife at approximately right angles.
Shows modified characteristics of both rotary and pain sliced. Produced in a variation of the way rotary cutting is done by which segments are mounted off center in a lathe. This result is a cut slightly across the growth rings.
Used on wood that have prominent rays. Wood is cut perpendicular to the growth of the rays and gives a rift or comb grain effect.
Every other veneer is turned over like leaves of a book. Also called edge matching
Adjacent sheets are joined side by side without turning.
Joining of veneers with intention of creating a casual unmatched effect is called random matching. Used in pre-finished wall grove panels
Vertical butt and horizontal bookleaf matching
Veneers are matched horizontally and vertically. Used in custom wall paneling and in furniture.
Four-way center and butt matching
applied to crotch or stump veneers to reveal figure.
Same as that of softwood where 3(number of plies is always odd) or more plies are laid with the grain direction of adjacent piles at right angles to each other.
Used in cabinet and furniture construction. Core made of sawed lumber to which crossband plies and face veneers are glued.
Plywood for use as a table, desk, and cabinet tops. Is made of wood particles fused under heat and pressure. Face veneers are then glued to the core.
Fire-resistant panels made with mineral cores. Face veneers then glued on.
Sizes for Hardwood Plywood
Commonly sold in 4x8ft panels, custom panels up to 40ft long and up to 7ft wide available.
Thickness can be from 1/8in. to 3 in.
Not typically or necessarily manufactured to meet industry standards. Species, type, match, core construction, and other requirements are as agreed upon by the seller and the buyer.
Plywood that conforms with requirements of HPVA HP-1 is called standard hardwood plywood. Used as stock panels, door skins, and in furniture manufacture.
Panels that are fabricated and stocked by a plywood manufacturer and sold through warehouses.
Comprised of largely hardwood veneer and used as a door skins to face solid and hollow doors.
Type I hardwood plywood
Made with waterproof adhesive and used where it might come in contact with water. Veneer core preferred for this type.
Type II hardwood plywood
Made with water-resistant adhesive. Used were it is not subject to contact with water. The majority of hardwood plywood is this type.
Technical type plywood
Made with same adhesive as type I plywood but varies in the thickness and arrangement of plies to provide approximately equal tensile strengths in length and width.
Face Grades for Plywood Panels
Veneers that must be matched in someway that to make a panel that has none to very few small burls, slight color streaks, and small patches. No defects like splits shakes, worm holes, or decay. Grades are AA(highest), A, B, C, D, and E (lowest).
Specialty Grade for Hardwood Plywood
Veneers that are unlike those of face grade. Examples are wormy chestnut, birdseye maple, and English brown oak.
Back Grades for Hardwood Plywood
Given a label of 1, 2, 3, or 4 with 1 being the most restrictive. These are used on surfaces that will not be exposed in the finished work.
Inner Ply Grades for Hardwood Plywood
J, K, L, and M are the four grades for inner plies. J is most restrictive and M is reserved for plies not directly adjacent to facing plies.
Oriented Strand Board (OSB)
Panels made using strands or wafers of wood mostly oriented in the long direction of the panel. Several panels are laid with the direction of their strands or wafers perpendicular to each adjacent sheet and bonded together to form a final panel. Should comply with requirements of ANSI A 208.1.
Read Pg 149-150 over history of Masonry.
read it to refresh
Clay Masonry Units
Burned Clay units used in building construction. Include brick, hollow clay tile, and architectural terra cotta.
Composed of aged clay to which admixtures and sand or pulverized, previously fired clay, called grog, are added.
Types of Clay used to make Clay masonry units
Surface clays: sedimentary clays, found near the surface of the earth.
Shales: Clays that have been subjected to high pressure until they have hardened almost to the form of slate.
Fire Clays: Clays found deeper in the ground that the other types that have refractory qualities., that makes them resistant to high temperatures and good for fire brick. Have few impurities and more uniform properties.
Manufacturing of Clay masonry units
Mining (aka winning), preparing, and storing raw material, then forming, drying, glazing, burning, cooling, drawing, and storing finished units.
First thing is tempering, produces a homogeneous, plastic mass ready for molding. Achieved by adding water to the clay in a mixing chamber called a pug mill. 3 methods used to form clay masonry units.
Stiff-Mud, Soft-Mud, and Dry-press Processes
Most commonly used method for forming clay masonry units. Clay is mixed with water (12% to 15% by weight). After thorough pugging (mixing), the tempered clay goes through a de-airing machine in which partial vacuum is maintained. Clay then goes through die which produces a clay column of the desired shape where texture can be applied. Wires then cut clay in to individual units and inspected. Acceptable ones are removed to be dried.
Only used for producing brick. Suitable for clay that contains to much water (20%-30%). Clay is mixed with water and the mixture is then formed into units in molds. Sand or water used to prevent sticking to mold. When sand used is called sandstruck and when water, waterstruck.
Used with clay with low plasticity. Mixed with minimum amount of water. (up to 10% by weight.) then formed in steel molds and under pressure of 500 to 1500psi.
Drying Clay masonry units
Before burning moisture needs to be evaporated. Done in drying kilns at 100 to 300 degrees Fahrenheit. Drying goes on for 24-48 hours checking for cracking.
Process to produce the finish on glazed tile, brick, and terra cotta. Glazes are sprayed onto masonry units before firing that come in almost any color. 2 type of glazing high-fired glazing where glaze is applied and brick is fired at normal firing temperatures, and low-fired glazing which allows for some colors not achievable at high-fired temperatures and is done by burning brick to maturity then cooling then applying glaze and then fired again at lower temperature to set glaze
Burning and Cooling
Burning is the process of baking the dried clay in kilns to produce finished units. 2 types of kilns used: periodic kilns and tunnel kilns. Takes 2-5 days to burn brick. 6 stages of burning evaporation of free water, dehydration(300 F -1800 F), oxidation(1000 F- 1800 F), vitrification(1600 F-2400 F, flashing, and cooling.
Cooling is the process of returning the masonry units to atmospheric temperature. Starts after max temp. reached. can take from 2-3 days.
Drawing clay masonry units
Process of unloading a kiln after cooling. Units are sorted, and graded, then taken to a storage yard or loaded directly to be delivered.
Compressive Strength of Clay masonry units.
Strength varies from the method of manufacture and temperature used to burn but can range from 1500psi to 20000psi. Stiff-mud process bricks tend to have better compressive strength.
Absorption of Clay masonry Units.
Clay used, manufacture process, and temperature of burning affect water absorption. Plastic clays, higher temperature burning, and stiff mud process tend to lower suction or absorption. This affect the bond between brick and mortar.
Durability of Clay masonry Units
Affect by pore size and burning temperature. The smaller the pour and higher the temperature then usually the higher the durability. Freeze thaw cycles and cryptoflorescence affect the durability of brick. ASTM C67 is the standard for brick not rated for effloresced
Color for Clay Masonry Units
Color is determined by type of clay used and how hot the clay is burned at. At higher temperatures the clay will become darker due to iron oxidizing in the clay. Darker bricks are stronger as they have been cooked longer and at higher temp. Black and dark red bricks are called clinker brick.
Textures for Clay Masonry Units
Textures can be applied or are effect of the moldings. Can be rolled on, scratched, brushed, or cut ranging from fine to medium to coarse. Typical textures are smooth, matt with vertical or horizontal markings, rugs, barks, sandmold, waterstruck, and sandstruck.
Size variation in Clay Masonry Units
Sizes vary as clay shrinks 4.5% - 15% in burning process. Different types of clay shrink at different rates so uniform brick size is not always possible.
Mostly composed of brick. Bricks are usually frogged, cored, or celled. This cuts down on weight and allows for even burning of brick. Some are solid throughout. Cores and cells can't take more that 25% or the unit's total cross-sectional area.
Nominal Size for modular brick is 4"wide by 2 2/3" high by 8" long.
Hallow Clay Masonry Units
Included hollow brick and hallow clay tile. Contain cells or cores that must exceed 25% in the collective area. Allows for quicker construction because it is lighter and easier to handle.
Tile used with its cells in horizontal plane is called side construction and vertical cells are end construction.
Hollow brick cross sectional area in plane parallel to the bearing surface is not less that 60% of gross cross sectional area measured in the same plane. Cored between 25% and 40%.
Architectural Terra Cotta
Is mostly used for copings and decorative cladding. Comes in many colors, shapes, textures, sizes. Ceramic Veneer used as a exterior decoration comes in adhesion type and anchored type. Adhesion type is smaller and installed w/ mortar, and anchored is larger pieces and is held in place by anchor and thick layer of grout.
Tile is other form or terra cotta. May be surfacing units or decorative elements with letters or number engraved and can be sculpted.
When ordering clay masonry units
make sure you write out the ASTM standards desired which determine the quality, grade, type, and class of the units.
Weathering standards for Clay Masonry Units
SW- Sever weathering- can withstand cold weather freeze cycles the best
MW- Moderate weathering- can withstand some cold weather freeze cycles
NW- Negligible weathering- can't withstand most freeze thaw cycles.
Facing Brick standards ASTM C216
FBX- Standards that are rarely required. These bricks have very small dimensional tolerance, small distortion tolerance, little chippage, and small color range differences from unit to unit.
FBS- Most commonly used which allows for some variation in dimensions, distortions, and small irregularities.
FBA- Allows even more variations and irregularities from unit to unit.
Hollow Brick Standards ASTM C652
HBS- Exposed exterior and interior walls where wider color ranges and greater variations in size are permitted than specified for HBX
HBX- Exposed exterior and interior walls where narrow color range and minimum permissible variation in size are required.
HBA- Where architectural effects are desired resulting from non-uniformity in size, color, and texture of units.
HBB- Where color and texture are not a consideration and greater size variation is permitted than specified for HBX
FTX- Exposed Masonry; smooth face, low absorption, and resistance to staining. Has high degree of mechanical perfection, minimal variation in color and face dimensions.
FTS- May be smooth or rough-textured, with moderate absorption and variation in dimensions, medium color range, and minor surface finish defects.
CMU (concrete masonry unit)
Units that are molded concrete units used in building construction as an integral part of the structure, as facing for or filler panels between structural elements, and to construct partitions. Include brick, split-face block, and other special units.
Materials in CMU
cementitious material, water, aggregates, and various admixtures.
Cementitious Material in CMU
Mostly type I portland cement (air entrained and high early strength can also be used) Fly ash and pozzolanic material used as an admixture to increase strength over time.
Aggregates in CMU
Constitute about 90% of the weight of CMU. Two main type are dense and lightweight aggregates. Dense is also know as normal weight and is usually sand, gravel, crushed limestone, and air cooled slag. Lightweight aggregates are usually expanded shale, clay, slag, coal cinders, pumice, and scoria.
Aggregates effect the weight, strength, and other characteristics of CMU.
Admixtures for CMU
Only limited number of concrete admixtures are beneficial to CMU. These admixtures are air-entraining agents, accelerators, coloring pigment, integral water repellents, and a few others.
Air Entraining agents increase the plasticity and workability.
Water-repelling agents- used at limited extent.
Accelerators- speeds up hardening of units in cold weather.
CMU molding units
After concrete is mixed, concrete is placed in molds (usually 8"x 8"x16" blocks). Machines then place blocks on steel pallets and on to steel curing racks. This is called off bearing.
Occasionally moist cured at normal temp. of 70-100 degrees F. Most are cured at low-pressure or high-pressure steam. only 40% strength at day 4.
Low-pressure steam curing of CMU
Is done in a kiln and accounts for most concrete masonry units produced. This allows rapid strength gain, which permits placing units in inventory within hours of being molded. 2-4 days it will be at 90% strength. Blocks are usually lighter color than moist cured blocks.
High-pressure steam curing of CMU
Units cured by application of steam in an autoclave under pressure of 125- 150 psi are called autoclaved units. Not as common today and are expensive because of shipping cost. Have high early strength and have same compressive strength after 24 hours of molding as a moist cured block of 28 days.
Cubing and storage of CMU
After curing, the blocks are assembled into cubes using 15 to 18 blocks on 6 layers. They are then secured together with steel bands. In storage they are stacked 3 or 4 cubes high and left there for a few days or several weeks.
Uses 2.75 to 4 sacks of cement per cubic yard. Uses lower water cement ratio of 2-4 gallons per sack. Aggregates are finer and are rarely as large or larger than 3/8in. Made more often with lightweight or porous material.
Compressive strength of CMU
In CMU highest strengths are obtained from wettest mixes. Max amount of water is usually not added to cut down on breakage of freshly molded units during handling before curing. Dry mixes don't compact as well and thus have lower compressive strength. Major influences on compressive strength are:
Type and gradation.
Type and amount of cementitious material
Degree of compaction attained in molding the units.
Moisture content and temperature of the units tat the time of testing.
Tensile strength, flexural strength, and modulus of elasticity
Tensile strength will range from 7% to 10% of the compressive strength, flexural strength from 15% to 20% of the compressive strength, and modulus of of elasticity from 300 to 1200 time the compressive strength.
Water absorption of CMU
Used to determine the density of the concrete. It is the measure of water in each cubic foot of concrete. Varies from 4 lb/cu ft for the heavy sand and gravel to 20 lb/cu ft for porous, lightweight aggregates.
Porosity and pore structure of a concrete influences permeability, thermal conductivity, and sound absorption.
Effects of water absorption rate in CMU
Not a desired trait, but can be accepted if other qualities are desired. Unconnected, air-filled pores in lightweight aggregate and in air-entrained cement paste impart the advantages due to porosity yet minimize permeability to water, air, and sound. If high water suction rate is problem use more water in mortar to offset the effects.
Carbonation in CMU
Causes irreversible shrinkage in masonry units as a result of a chemical reaction within the concrete brought about when it absorbs carbon dioxide from the air.
Volume Changes in CMU
Affected by temperature, changes in moisture content, and carbonation. These effects of swelling can cause cracks. When mortar is curing if not treated properly then this can lead to cracking.
Surface Texture for CMU
Many varieties of textures. This can be controlled by:
1. the gradation of the aggregate
2. the amount of water used
3. the degree of compaction at the time of molding.
The surface can also be ground to produce desired texture.
Color of CMU
Comes in off-white, gunmetal gray, light tan, brownish shades, blue, buffs, greens, reds, and slate gray. These colors are obtained by using pure mineral oxide pigments.
Types of Concrete Brick
Building Brick- Either completely solid or have a frog in the. are 4" wide x 8" long and vary in thickness.
Slump Brick- Brick that sags or slumps when removed from mold that is used for special and unusual appearance.
Are either solid load bearing units, hallow load bearing units, or hallow non-load bearing units. Solid unit has a core less than 25% of the total cross-sectional area of the unit, and a hallow unit has a core more than 25% of the total cross-sectional area of the unit. Made in modular sizes of 8x8x16 in. but actualy 75/8x 75/8x 155/8 in.
Types of Concrete Block
Corner - One flush end for use in pilasters and piers and on exposed corners.
Bullnose- Have one or more small rounded corners. Used were rounded corner desired.
Jamb or sash- used to help instillation of windows, louvers, and other fillers
Solid top- Used for bearing surface on top of retaining walls
Lintel- U- or W- shaped. Used for constructing horizontal lintels or beams
Partition- Used to build non-load-bearing partitions and walls.
Types of Concrete Block Cont.
Return (L) corner- Used at 6",10", & 12" walls to keep constant horizontal coursing with the appearance of full-length units and half-length units without cutting of the corner units.
Control joint- Various types used to construct vertical shear-type control joints.
Special units of CMU
Split-face - Are solid or hollow units that are produced in parallel pairs and fractured lengthwise by machine. Units then laid in wall with fractured faces exposed. Units are available in random sizes, so that broken joint patterns can be used.
Slump- Same as slump brick but larger.
Faced- Units with ceramic, glazed, plastic, polished, or ground faces.
Decorative- Some have beveled face shell recesses, more than one plane, clear rectangular or curved holes cut through them.
Chimney- Designed for
Special units for CMU cont.
Chimney- Designed for use with a flue lining in chimneys.
Pilaster- used in plain or reinforced pilasters and columns.
Grades for load-bearing CMU
Grade N- are suitable for general use in exterior walls above or below grade, and exposed to moisture or weather, and for interior walls and backup.
Grade S- Suitable for use only where it will not be exposed to moisture or weather.
Moisture controlled CMU
There are 2 types
Type I units are available in grades N and S (N-1, S-1) and are restricted to a definite moisture content according to ASTM standards.
Type II units are not restricted to a definite moisture content.
Mortar and Grout
Mortar- Combination of one or more cementitious materials (portland Cement, lime, or masonry cement), a well graded aggregate, and enough water to mix into a plastic, workable quantity.
Grout- 2 types, one is used to fill voids in both reinforced and unreinforced masonry. The second is a tile setting grout used in filling the joints in unit masonry or stone paving and flooring.
Mortar and Grout Plastic Properties- workability
Workable mortar is uniform, cohesive, and of a consistency that makes it usable by a mason. It needs to be able to not segregate particles when mixed, hold weight of the units, cling to vertical surfaces of masonry units, and easily extrude from the mortar joints without dropping or smearing. Water retention, flow, resistance to segregation, and other factors.
Grout is designed to pour and therefore must flow freely without being too soupy, and must be uniform.
Mortar and Grout Plastic Properties- Water Retention.
Prevents rapid loss of water and a resultant loss of plasticity when the mortar or grout contacts a masonry unit with a high absorption rate. Water retention needed to prevent bleeding which lowers the bond strength.
Initial Flow- mortar
Initial flow is measured by a lab test of a truncated cone of 4in. in diameter is placed on a flow table. Flow table then is raised and lowered 25 times in 15sec. mechanically at a height of 1/2 in. The mortar then flows outward increasing the diameter. The flow is a ratio of the final diameter to the original. ASTM C270 states that initial flow be 110% +/- 5%.
Flow-After-Suction test- Mortar
Same sample of mortar that is used in initial flow test is placed over an absorbent filter in a perforated metal dish mounted over a vacuum device. Vacuum removes some water from mortar. The mortar is then tested in the same way for initial flow. The laboratory value of water retention is the ratio of flow as a percentage. The formula is (A/B) X 100, where AA is flow after suction and B is flow after mixing. ASTM C270 requires a water retention of not less than 75%.
Hardened Properties of Mortar
Properties are bond strength, volume change, water tightness, rate of hardening, and mortar color. Bond strength and compression strength are the most important qualities
Bond Strength of Mortar and Grout
Most important characteristics of hardened mortar and one of the most for grout. Properties that affect bond strength are amount of cementitious material used, amount of water used, water retention, air entrained content, and compressive strength. Bond strength increases if the mortar had good flow and fills in pores of masonry unit and bonds better. If air content exceeds 12% bond strength decreases. Surface texture affects bond strength.
Durability of Mortar and Grout
Measured in its ability to resist water penetration. If water enters and freezes it can damage mortar by spalling or popping off. Water can also crystallize salts in mortar and cause damage called subflorescence or cryptoflorescence. If slat is carried to the surface and deposited its called efflorescence. This does not damage but is unsightly. Air entrainment should not be used on portland cement mortar but is ok to be added in masonry cement mortars.
Compressive Strength of Mortar and Grout
Depends on the amount of portland cement in its mixture. A large flow will reduce the compressive strength of mortar. Not common for mortars to fail in compressive strength so only moderate compressive strength is needed. Compressive strength is not as important as bond strength, workability, and water retention. Strength should never be more than is needed as it can be stronger than the units and crack if it flexes.
Volume change in mortar
Shrinkage is negligible if mortar is properly placed and tooled in joints.
Color affected by the atmospheric conditions, the moisture content or the masonry units, the admixtures used, the control exercised over the mixture, and the timing of the mason's tooling of the joints. Must control mix day to day to keep color constant. Tool joints at same amount of time of after placement to keep shade the same color.
4 Kinds of mortar and 2 kinds of grout
Mortars: sand-lime, portland cement, portland cement-lime, and masonry cement. Only portland cement-lime or masonry cement mortars are used largely today and are covered by ASTM C270.
grouts: portland cement and portland cement-lime. Lime mortars not suitable for grout and masonry cement not usually permitted in grout
Harden at a slow, variable rate. Develop low compressive strength, have poor durability, deteriorate over years. Can be raked from joint with finger. Have high workability and high water retention and are more flexible than portland cement mortars.
Portland Cement Mortar and Grouts
Harden at a quick consistent rate and develop high compressive strengths. Have good durability, but workability, and water retention are to low. They are used for the installation of architectural terra cotta ceramic veneers. May be used in other types of masonry but not in engineered unit masonry walls.
Portland Cement-lime Mortars and Grouts
Are widely used. The portland cement contributes durability, high early strength, a consistent rate of hardening, and high compressive strength. Lime adds workability, water retention, and plasticity. Both contribute bond strength.
Masonry Cement Mortars
Made using proprietary mortar mixes called masonry cement. Advantages is that it is readily available, convenient to mix, and produces a mortar with generally good work-ability. Main disadvantage is that ASTM C91 doesn't limit ingredients or proportions, or control the types of quantities of admixtures a produce can include in it. Performance is thus unpredictable. Not recommended for use in reinforced masonry or in masonry that may have to withstand lateral forces or heavy loads.
Mortar and Grout Materials
ASTM C270 lists standards for mortar masonry and ASTM C476 lists standards for grout ingredients.
Portland Cement in Mortar
ASTM C150 covers 3 types of portland cement used in mortar and grout
Type I: used when no special properties needed
Type II: Used when moderate sulfate resistance or moderate heat of hydration is desired.
Type III: Used when high early strength is needed, such as in cold weather.
Conform to ASTM C91. Not used in grout. Is easier to have pigments premixed in to cement and provide uniform color throughout. Air entrainment of masonry cement is allowed to go up to 22% in ASTM C91. Should be limited to 12%.
Should conform to ASTM C5. Must always be mixed with water to consistency of putty and stored for 2 weeks long before use. Only used today for preservation work to match existing mortar.
Conform with ASTM C207. Is quicklime that has been slaked before backaging, converting the calcium to calcium hydroxide. Can be mix and used without delay. Much more convenient than quicklime. Only allows use of type S for masonry mortar and grout.
Only aggregates that are suitable for use in masonry mortar is material that complies with ASTM C144. For grout its ASTM C404.
Aggregate gradation for masonry- and stone setting mortar.
Aggregates for general use should be graded to include all particle sizes from very fine up to 1/4in. Aggregates with lass than 5% very fine particles produce harsh, hard-to-work mortars that need additional cement or lime. Aggregates in joints narrower that 1/4in. wide should have 95%passing thorough a No. 16 sieve and 100% thorough a No. 8 sieve. Many commercial sands don't meet gradation limits in ASTM C144.
Aggregate gradation for grout
ASTM C476 has 2 categories fine and course for aggregates. ASTM C404 also has several subgrades.
Colored aggregate mortar
Limited amounts of color achievable as the aggregate is what gives color.
Colored pigment mortar
Pigment is added to cement and must be added in fieldfor colored portland cement-lime mortars. Usually use metallic oxides to get color. Organic pigments should be avoided. Used the minimum amount of pigment so it doesn't affect the strength and durability. American Concrete Institute's ACI 530.1/ASCE 6/TMS 602 limits the amount of pigments to put in.
Admixtures for grout and mortar
Some admixtures are permissible like color pigments. Air-entraining agents, water-repellents, accelerators, retarders, and antifreeze compounds are allowed.
ASTM C476 prohibits any kind of antifreeze compound in grout.
Type M Mortar
High-strength, somewhat greater durability that other types. Used in reinforced masonry and in high compressive strength. Used in subgrade walls, walks, manholes, sewers.
Type S Mortar
medium-high-strength mortar. Used where bond and lateral strength important. Recommended where reinforced and non-reinforced masonry with max flexural strength needed. Used for setting beds in granite, marble, and slate in other than paving installations.
Medium-high-strength mortar. Recommended for general exposed use above grade where high compressive strength and later strengths not required.
low-strength mortar suitable for only general interior use in non-load-bearing masonry and for tuck pointing. Not use were subject to freezing.
No mortar perfect for all situations. Pick mortar based on type that is not stronger than what you need for compressive strength, where it will be used, and masonry type. Mortar should be designed for specific use.
In cavity walls where wind velocity will exceed 80 miles per hour type S mortar should be used. In lower wind velocity areas type S or N can be used.
Type M,S,N or O types are accepted but aggregates should be small enough to go through No. 16 sieve.
Dirt Resisting Mortar
Add aluminum tristerate , calcium stearate, or ammonium stearate limited to 3% of the weight of the portland cement in the mortar.
The process of refilling a joint which some of the mortar was removed. Tuck pointing mortar must be prehydrated.
Two different mortars in same joint
Fill joint with regular mortar first then rake back about 1/2 in. of mortar. Then go in and fill in with the colored or desired mortar.
Grout types used and proportions
ASTM C 476 is classified as either fine or coarse. The only difference is the gradation of the aggregate.
Grout and Mortar Mixing
Grout should have enough water to have a slump of 8-11 in. Should be used within 1 1/2hr. ASTM C270 and C476 give proportions for the ingredients in mortars and grouts. Make sure to used container to measure ingredients used. Over sanding is common and can ruin batch.
Mortar mixing should always be mechanically mixed unless project is very small. Grout should always be mechanically batched mixed regardless of batch size.
Sand goes first across the bottom of the mixing box. Then cementitious materials and other ingredients added and mixed dry with a hoe. 3/4 total Water should be added next and stirred thoroughly to get uniformly damp. Rest of water added in small amounts while stirring. let stand for 5 minutes stir again.
Cold Weather Mixing
Temp of mortar or grout should be between 70-120 degrees when outside temp is below 40 degrees F. Higher temperatures can result in faster hardening. Don't heat water above 160 degrees. Heat sand slowly in freezing weather to get rid of ice. No use of antifreeze admixtures.
Retempering mortar and grout
Retempering is the process of adding water to mortar that is already mixed and has evaporated some of its water. It sometimes not allowed or limited by code. Should not be done if mortar had begun to set.
Joint Reinforcement, ties, and anchors for unit masonry
All metal joint reinforcement, ties, and anchors should be copper-coated steel, hot dip galvanized steel, or stainless steel to prevent corroding or rusting.
Joint reinforcement for use in horizontal courses of interior masonry and masonry protected from weather should be zinc-coated, cold drawn steel wire(ASTM A82) or Type 304 Stainless steel wire(ASTM A580). Joint reinforcement in exterior walls should be Type 304 stainless steel wire(ASTM A580)
Wire Mesh Ties
AKA hardware cloth is being used to anchor non-load-bearing partitions to intersecting masonry.
Cavity wall Ties
Ties for use in exterior cavity walls. Ties should be long enough to permit the ends of the tie to be embedded in the outer face-shell mortar beds of hollow units or the center of mortar beds of solid units.
Faced Wall Ties
Ties used in faced walls should meet the same requirements give for cavity wall ties.
Veneered Wall Ties, wood studs
The ties usually used for brick veneer over wood studs are 22 gauge, 6in.-long 7/8in. wide corrugated galvanized steel. These are usually bent up and nailed through the sheathing into the underlying studs.
Veneer Wall Ties, Metal Studs
Ties for masonry veneer over metal studs should be triangular, flexible, stainless steel wire ties similar to those used to anchor masonry to steel structural members. The fixed portions of the ties should be screwed through the sheathing to the studs. The flexible triangular portion of tie then is threaded through support and built into masonry as erected.
Used for embedded slots or inserts in concrete should be wide and long enough to permit the ends of the tie to be embedded in the outer face shell mortar beds of hollow units or the center of mortar beds in solid units.
Rigid Steel Anchors
Used for anchorage of load-bearing walls and fire walls should be 1 1/4in by 1/4in. steel with the ends turned up not less than 2 in. Should be not less than 16 in. long for 8 in. thick walls and not less than 24 in. long for 12in. thick walls.
Structural Reinforcement for unit masonry walls
Structural reinforcement for unit masonry walls consists mainly of steel bars and welded wire mesh.
Reinforcement, ties, anchors, and support systems for stone
Various types of reinforcement, ties, anchors, and grid support systems are used in stone construction. All devices that come in contact with stone should be fabricated from AISI Type 304 stainless steel. (ASTM A666)
Flashing is installed help prevent water from entering and to collect water that entered the masonry and divert it through weep holes. Formed from sheet metal, bituminous fabric membranes, plastic sheet materials, or combination of these materials. Important to use durable flashing material.
Early dwellings of humans
natural stone caves. When caves weren't available, shelters were made of wood and animal skins. People then made crude stone huts. Shaped stone used extensively after iron stone working tools developed where no mortar used just accurate cut stones.
Who introduced lime mortar?
Who introduced hydraulic mortar?
The Romans. Allowed for much stronger stone structures to be made and much longer spans.
History of masonry units
Brick replaces stones as it is lighter and easier to handle. Eventually concrete masonry units and steel framework would also replace brick units. Stone and brick used for visual look not structural purpose now.
regular or irregular stone units that are gathered from steam beds and fields. Most often used for fences and site walls, for landscaping, and as riprap.
rough-cut or blasted stone used in walls
Thin slabs of stone that is used primarily as flooring or paving.
stone that is cut with square corners. It may be thin slabs, large or small blocks, or sculptured shapes.
Consists of large pieces of dimension stone.
Is small rectangular blocks of dimension stone
Made by crushing stone. Is used to fill beneath building slabs and paving; drainage fill; riprap; as aggregate in concrete, terrazzo, and asphalt; and in landscaping.
Relatively small, smooth stone gathered from stream beds. Used in locations like crushed stone.
Results from quarrying , milling, and finishing of stone. Is used as mulch and for other landscaping purposes.
Stone used today
limestone, marble, granite, and slate.
Limestone ASTM C568
is sedimentary rock made of calcium carbonate (calcite) or dolomite. Is either oolitic which is quarried in Indiana and is weaker and less crystalline that dolomitic limestone. Dolomitic is the other type and can take a polish when oolitic can't. Limestone colors range from light creamy buff to brownish buff or silver gray to bluish gray and some green. Not suitable for acidic environments or exposure to chemicals that will melt ice or snow.
Marble ASTM C503
Is metamorphic stone composed of calcite and dolomite that has recrystallized under heat and pressure over long time. Has 4 categories: I Calcite, II Dolomite, III Serpentine, and IV Tavertine. Has many colors. Must be able to take polish. Not to be used in areas with heavy traffic as it will wear down the polish.
Granite ATSM C615
Granular igneous rock consisting mostly of quartz or feldspar. Ranges in color from pink to dark gray. Nearly impervious to water. Other stones that don't meet the chemical and mineralogical requirements are also sold as granite. These come in black, brown, green, and buff. Can be used under sever weathering conditions and in contact with ground.
Slate ASTM C629
is microcrystalline metamorphic rock formed originally from clay. Primarily used for paving and roofing. Comes in red, purple, green, blue, and black.
The removal of stone from the ground. Different methods of removing stone depending on type of stone and the use to which it will be put.
Process of cutting quarried stone splits into blocks and slabs and further refining them into final shapes that will be used in a building.
Diamond belt saw is drawn through the stone at intervals of about 4ft. 6in. cutting bedrock into sections about 15ft. deep and 50ft long. Air bags inserted into the sawed joints and inflated tilting a section away from the bedrock. Holes then are drilled into turned section parallel and perpendicular to the grain. Sections then broke into 8ft long blocks. Rock splitters are inserted in hole that split rock. Blocks are 4x8x31/2ft. These blocks are tagged and stored until transported to mill.
Milling of Limestone
Blocks cut into smaller blocks or slabs. Not usually cut into slabs or blocks less than 2in. thick. Max slab size is dictated by thickness. Natural stone contains moisture when quarried. Moisture dries and stone stabilizes, this is said to be seasoned. Until it is completely seasoned color variations can occur and no water repellents should be used.
Similar to method of limestone. Can be used in thicknesses as small as 3/4in.
Some types of granite can be quarried using a wire cutter, in which large diamond studded wire is drawn through the stone at high speeds. Most is quarries by drilling, blasting, or the application of extreme heat using a jet burner, which causes the granite to split away (spall) from bedrock. Can be cut and installed in sheets as thin as 3/8 in. but thicker is advisable.
Process of grinding, polishing, or other treatment to produce the desired finish on a piece of cut stone.
is coarse pebbled surfaces made by using a coarse abrasive during sawing.
results from the application of direct flame at high temperatures (w/ blow torch) This usually is seen in granite and some limestone. Most stones cannot withstand this treatment.
Any surface made using hand tools
Stones having a honed finish are smooth, like polished ones, but are nonreflective. Honed finishes are achieved by rubbing by hand or machine using abrasives.
A plucked surface has a rough finish made by rough-planing the surface and breaking out (plucking) small particles.
Polished stone has a mirror-like surface. Only crystallized stone can take polish. Does not affect porosity of stone.
Surface is rough and irregular. It is sawed on the top and bottom, and the face is exposed by splitting and is then dressed by machine.
Rubbed or Fine-rubbed
Achieved by rubbing with abrasives, such as sand or grit. A rubbed finish has occasional light trails or scratches. A fine rubbed finish is smooth but has no sheen.
Stone face has a deep joint effect cut by machine and sometimes finished by hand.
Has a smooth mat surface
is simply the rough sawcut surface of the stone with no other treatment applied. Sawcut material is seldom used where it will be visible in completed building, but tumbled marble is often made from sawcut material; if not tumbled enough, it will show circular saw marks.
A reproduction of a sculptor's model carved in the stone by hand.
is a rough, irregular surface made by sawing the stone at the top and bottom and splitting it.
Design and Construction with stone
May be laid in mortar beds and supported by the stone below or supported from the structure by metal. May be adhered to backing panels of concrete or metal. Used to build solid walls, arches, and vaults; as a facing over masonry; or as cladding.
Traditional stone setting
Traditional mortar bed setting is still used today, usually for retaining walls, planters, and the like; for installing stone copings and trim in masonry walls; and in restoration work on existing stone structures. Stones laid in this method are placed either as rubble or ashlar. Ashlar is cut stone with squared corners. Large blocks with square corners is dimension stone.
Method to traditional stone setting
First setting bed is placed then the stones are set in the bed. The joints are raked back. When the bed has set, the joints are either filled with mortar and tooled or filled with a sealant.
Stone cladding may be set on a field erected grid system of stone anchors, fasteners, and metal struts and braces. Very thin stone cladding can be set as panels in aluminum frames. Thin stone cladding panels may be applied as facing on concrete panels. May also be preassembled into panels on metal support systems and mechanically attached to metal frames or the structure.
Practicality of thin stone cladding
Cladding today is usually done in thicknesses of 2in. or less. This makes it easier to damage from wind, rain, freezing, and chemicals, but the ease of erecting lighter stone, and the reduction of the load on the structure often makes the use of thin stone cladding worthwhile.
Glass unit masonry
Are made with clear, textured, reflective, and heat-absorbing glass and made either solid or hollow. Can be installed in mortar joints, aluminum frames, or in frameless systems held together with sealant. Used in interior and exterior. Can be placed vertically or horizontally.
Hollow units made by joining two molded units together, with a partial vacuum between them. Face thickness varies. Wide variety of patterns usually made on the inner face of the hollow block. May have ceramic faces fused onto glass block. Solar units are coated on one or both faces with reflective oxide. Both single and double cavity blocks are available. Ambient heat control is good in the single cavity and better in the double cavity block.
Mortar for Glass Block
Is type S portland cement-lime mortar in accordance with ASTM C270. In exterior panels, waterproofing admixture is added. Color mortars are sometimes used.
Accessories for Glass Block
Panel reinforcement, panel anchors, expansion strips, spacers, and aluminum- or steel- channel perimeter chases.
Framed system accessories are separators, aluminum framing systems, and plastic foam tape.
Installation with Mortar joints for glass block
Lay the blocks with both horizontal and vertical mortar joints between the blocks. Units may be anchored at head and jambs using sheet metal channels. Can also be anchored at jambs using panel anchors, dovetail wire ties to dovetail slots in concrete, and trapezoidal ties welded to steel columns. Joints are usually recommended to be finished with a sealant.
framed (grid) installation methods for glass block
In framed systems, aluminum grid is used to place blocks in and then is held in place with foam tape to allow for expansion and sealed with silicon sealant.
Frameless is like a window frame. Blocks are set into the overall frame. Sealant is applied to the vertical edges or each block and a vertical separator is installed. A horizontal separator is placed across it to act as a joint reinforcement. Sealant is applied as components installed.
reinforced Hollow Masonry
Reinforcing and grout are placed in the cores of concrete masonry units or hollow brick. Concrete masonry laid with full face shell bed joints. Head joints are filled with mortar to a distance from the face equal to the face shell thickness. Cross webs adjacent to cores that will be filled with grout fill solidly with mortar. Hollow brick should be laid with full head joints, but the cores be left open in the bed joints. Masonry units be placed so reinforcing steel can be placed and filled.
Reinforced sold masonry (reinforced grouted masonry)
Placed between two wythes of masonry. Laid with completely filled bed and head joints. Cores and joints adjacent to spaces to be filled with grout should also be filled with mortar. Reinforcing bars are placed vertically in walls and tied to horizontal bars.
Patterns formed by masonry units and mortar joints is pattern bonds. May be structural or for decorative appeal. Structural bond is the method of interlocking masonry units using headers or meal ties.
simplest of basic patterns. No headers. Metal ties are used for structural bond.
Common (American) Bond
Similar to running bond except there are course of full length headers at every fifth, sixth, or seventh course. A 3/4 brick starts each header course at the corner
Has alternate stretchers and headers in each course. Where headers not used for structural bonding, half-brick, called blind headers, may be used. there are two methods of stating the corners. Dutch corner, three-quarter brick starts each course. In the English corner, 2in. or quarter-brick closures used.
Alternate courses are composed of headers and stretchers. The joints between stretchers in all courses line up vertically. Blind headers are used except in structural bonding courses.
English Cross or Dutch Bond
Variation of English Bond. Vertical joints between the stretchers in alternate courses do not like up vertically, but center on the stretchers in the courses above and below.
Brick is laid vertical joint not overlapping each other. Usually bonded to backing with ridged steel ties.
Patterns are altered by changing the color and texture of individual units, by changing the joint types used, and by recessing or projecting individual units, courses, or wythes.
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