Masonry Units and Brick | 2nd Year, 2nd Semester

• Masonry works are to be studies in the 2nd semester of the 2nd year.
• This course aims to improve masons' knowledge, skills, and attitudes according to industry standards focusing on specialized skills as well as workplace skills like teamwork and safety.
• After completing this module, students should be able to identify types of masonry units and masonry along with its processes.

Masonry Units

• The American Society for Testing and Materials (ASTM) publishes the most widely accepted material standards, that have gone through a review process by construction industry segments
• Specifications for masonry units like clay, shale, concrete, or glass block are provided by ASTM Standards and referenced in building codes.
• The types are clay building brick, stone, concrete, and others.

Brick Masonry

• Brick is special among masonry materials for the fire resistance and size which fits the human hand, which makes it easy to manipulate
• Bricks are produced in small, dispersed factories from local clays and shales due to their weight and bulk, which makes them expensive to ship.
• The raw material is dug, crushed, ground, and screened to reduce it to a fine consistency, and then tempered with water to produce a plastic clay for forming bricks.

Types of Making Bricks

• These include the Soft Mud Process, Dry Press Process and the Stiff Mud Process.

Soft Mud Process

• The oldest method involving moist clay (20-30% water) pressed into molds, either by hand or machine.
• Dipping molds in water produces water-struck bricks with a smooth, dense surface. Dusting molds with sand before forming creates sand-struck or sand-mold bricks, with a matte-textured surface.

Dry Press Process

• Used for clays that shrink excessively during drying, with clay mixed with minimal water (up to 10%) pressed into steel molds by a high-pressure machine.

Stiff Mud Process

• The high-production stiff mud process is also the least costly and most widely used today.
• Utilizes clay with 12-15% water passed through a vacuum to remove air, then extruded through a die.
• Textures or colored clays can be applied to the surface and automatic cutter wires slice the clay into bricks.

Firing Bricks

• Bricks are dried for 1-2 days in a low-temperature dryer kiln before firing.
• Before modern kilns, bricks were fired in a clamp, a loose array covered with earth or clay, with a wood fire maintained for several days.
• Today, bricks are burned in either a periodic kiln which is fixed ,loaded, fired, cooled, and unloaded, or a continuous tunnel kiln, where bricks pass through on railcars to emerge fully burned.
• The initial burning stages involve water smoking and dehydration, followed by oxidation and vitrification at 1800-2400°F (1000-1300°C), transforming the clay.
• A stage called flashing can be used to create color variations, and bricks are cooled under controlled conditions.

Bricks Quality

• The firing process takes 40-150 hours and is continuously monitored.
• Brick color relies on clay composition, fire temperature, and kiln chemistry
• Higher temperatures produce darker bricks, and iron turns red in oxidizing fires and purple in reducing fires.
• For bright colors, bricks can be glazed like pottery during firing

Brick Sizes

• There is no "standard brick" so designers review samples and adjust drawings accordingly.
• Length dimensions must account for mortar joints. Custom sizes are available with sufficient lead time.

Brick Classifications

• These brick types are categorized as facing brick (ASTM C216), building brick (ASTM C62), or hollow brick (ASTM C652).
• Facing bricks are for structural and nonstructural uses where appearance matters.
• Building bricks are used where appearance isn't important and specified as solid units.
• Paving bricks (ASTM C902) must resist freeze-thaw, water absorption, and abrasion.
• Firebricks (ASTM C64) line fireplaces/furnaces and resist high temperatures.

Brick Laying

• Bricks are laid for visual or structural reasons.
• Walls can be single wythe stretcher courses or use headers to bond multiple wythes.
• A head joint is the mortar joint between bricks in a course, while a bed joint is between courses, and a collar joint is between wythes.
• A course is a horizontal layer of masonry units.
• A wythe is a vertical layer of masonry units, one unit thick.
• Different brick positions include stretcher, header, soldier, and rowlock shown in the figure.

Structural Bonds in Brickwork

• Structural bonds for brickwork include common bond, Flemish bond, and English bond.
• Running bond is typically used on building exteriors with a single wythe cavity wall.
• Solid brick walls with any desired bond can be used inside, but bonded brickwork can be difficult to justify for small constructions.
• Running bond isn't a structural bond, partial closer bricks are needed at corners on others in order to make the header courses.

Steps in Brick Laying

• Laying leads is labor-intensive.
• A mason's rule or story pole establishes accurate heights.
• Work is frequently checked with a spirit level to ensure flat, plumb surfaces.
• A mason's line is stretched between leads using L-shaped line blocks to precisely locate each course.

Joint Tooling

• Joints in brickwork are tooled to give neat appearance and meet visual/weather-resistive requirements.
• Vee and concave joints shed water and resist freeze-thaw damage outdoors.
• Raked or stripped joints accentuate patterns indoors.
• The excess mortar squeezed out is swept off with a brush, leaving a finished wall

Reinforced Brick Masonry

• Reinforced brick wall are created by constructing two wythes of brick 2 to 4 inches (50-100 mm) apart,
• Reinforced brick walls have reinforcing steel placed in the cavity, then filled with grout, a Portland cement, aggregate, and water.
• Methods for grouting reinforced brick walls include low lift and high lift.
• Low lift grouting involves constructing masonry up to 4 feet (1200 mm) before grouting.
• Vertical reinforcing bars are inserted, projecting 30 bar diameters and the cavity is filled with grout.
• High-lift grouting involves grouting the wall a story at a time.
• The cavity is cleaned and the hydrostatic pressure is resisted with galvanized steel wire ties.
• Then reinforcing bars are placed and grout is pumped into increments which are not more than 4 feet (1200 mm) high.
• It is generally easier for small work where the grout is poured by hand, and RBM walls are stronger against vertical and flexural loads, and shear loads.

Stone Masonry

• Stone is for walls, arches, and vaults (stone masonry) or mechanically facing a building (stone cladding).
• Rubble can be rounded stones to broken pieces either coursed or uncoursed.
• Ashlar masonry can be coursed/uncoursed using same-sized or different-sized blocks.
• Stone masonry is often combined with concrete masonry to reduce costs.

Stonework

• Mortar joints in stonework are raked to a depth to get the desired profile and provide a good weather seal.
• Exceptional care is taken to keep stonework clean by using non-staining mortars.
• It can be cleaned with mild water, soap and a soft brush.
• A clear sealer or water repellent can be used to prevent staining and weathering.

Building Stone

• Building stone are for construction.
• Stone is classified geologically by formation: igneous, sedimentary, metamorphic.
• Factors influencing stone choice include type, regional features, and cost.
• For commercial purposes, ASTM C119 classifies stone into six groups: Granite, Limestone, Quartz-Based Stone, Slate, Marble, and Other.

Granite Group

• Granite is the most common igneous rock used in construction in North America as a mosaic of mineral crystals, principally feldspar and quartz (silica).
• It can include colors like gray, black, pink, red, brown, buff, and green.
• Granite properties are nonporous, hard, strong, durable.
• Requirements for granite dimension stone are defined in ASTM C615.

Limestone Group

• Limestone is one of the two principal sedimentary rock types used in construction.
• Requirements for limestone dimension stone are specified in ASTM C568.
• Can include colors like white through gray and buff to iron oxide red.
• Limestone is porous and stores considerable groundwater, or quarry sap, when quarried.
• According to ASTM C568, limestones are split into levels for construction, with all 3 being suitable.

Quartz-Based Dimension Stone Group

• Includes sandstone.
• Requirements for quartz-based dimension stone are specified in ASTM C616.

Slate Group

• One of the two metamorphic stone groups utilized in building construction.
• Slate is formed from clay, with closely spaced planes of cleavage that is split into sheets for wall facings.
• Requirements for slate dimension stone are specified in ASTM C629.

Marble Group

• The second major metamorphic rock groups.
• Marble is can be carved and polished and marble is graded by The Marble Institute of America.
• Requirements for marble dimension stone are specified in ASTM C503.

Other Stone Group

• The ASTM C119 includes less frequently used building stones such as Travertine, Alabaster, greenstone, schist, serpentine, and soapstone.
• Requirements for travertine dimension stone are specified in ASTM C1527.

Stone Types

• Fieldstone is rough building stone obtained from riverbeds and rock-strewn fields.
• Rubble consists of irregular quarried fragments with at least one good face to expose in a wall.
• Stone is quarried and cut into rectangular shapes (dimension stone); large slabs are often referred to as cut stone and small rectangular blocks are called ashlar.
• Flagstone consists of thin slabs of stone used for flooring and paving.

Stone Dust

• Crushed and broken stone are for site work as fill, base layers, and surfacing materials and and and and aggregates in asphalt or concrete
• Stone dust and powder are used for walks, drives, and mulch.
• Harder stones like granite are quarried using diamond drilling techniques to make the cut.

Stone Prep

• the stone producer works from the architect's drawings to make a set of shop drawings that show the shape and dimension of each individual stone in the building
• After being checked architectural drawings in the mill that are followed when producing the stones.

Stone Selection Factors

• Physical characteristics of the stone type varies across regions, location and supply quantities.
• Fitness and properties can usually be extrapolated from past experience.
• To test the stone, physical properties should be proven with stone from a unproven / new source

Physical properties that stone should be tested on for stability

• Water absorbtion - The less absorptive the stone, the less susceptible it is to freeze thaw damage and chemical detoriation
• Density - Is a measure of durabilty correlating with higher strenght and lower absorbtino

Material Strength Testing

• Compressive Strength - for stone used in Load bearing walls
• Modulus of Rupture - Resistance to share the ension forces for metal anchors used to attach the stone to the buildings
• Flexural Strength - determines wind load resistance wind load of the stone panels

Explore masonry units like clay, stone, and concrete according to ASTM standards. Learn about brick masonry, its fire resistance, and convenient size for handling. This module enhances masons' skills and knowledge, focusing on industry standards, teamwork, and safety.