Construction Materials PDF

Chapter 6 Construction Materials 1 Introduction Construction Materials: Soil Asphalt Aggregates Masonry Steel Wood Concrete...

Chapter 6 Construction Materials 1 Introduction Construction Materials: Soil Asphalt Aggregates Masonry Steel Wood Concrete Glass/plastic/aluminum/composite/… Mortar CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 2 2 1  Materials Selections Based on the following criteria, materials are selected for a particular structure/facility: Economic factors Type of construction Required mechanical and non-mechanical properties of materials Considerations for sustainability The aesthetic point of view CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 3 3 Economic Factors Raw materials must be available, extracted, manufactured, transported, placed, and maintained. The following factors require economic evaluation: Material Cost Maintenance Cost Labor Cost Energy Efficiency Availability Environmental Regulations CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 4 4 2  Construction Type of structure/facility Foundation Requirements Technology and Expertise Quality and Performance Climate and Environmental Conditions Sustainability CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 5 5 Non-Mechanical Properties of Materials Density Thermal Expansion Surface Properties: Corrosion and Degradation Abrasion & Wear Resistance Surface Texture CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 6 6 3  External Loads on Structures There are different types of external loads that can be applied to a structure: Dead load Soil/hydrostatic pressure Live load Thermal load Snow load Settlement load Wind load Impact load Earthquake load Blast load CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 7 7 Mechanical Properties of Materials Elements/components of a structure can be deformed and finally ruptured based on (1) the magnitude of external loads, (2) the geometry of elements, (3) form of the structure,(4) connections, and (5) the mechanical properties of materials that are: Strength Ductility Toughness Elasticity Hardness Creep Resistance Fatigue Strength Thermal Conductivity Thermal Expansion Corrosion Resistance Density … CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 8 8 4  Stress & Deformation Tensile stress Each member of a structure may experience Compression stress one or more types of Bearing stress stress and strain. Shear stress  Different structural materials have varying Strain (relative deformation) stress limits. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 9 9 Steel Steel can be used solely or coupled with other materials. It has high strength in tension and compression and can undergo large deformations without fracture. Main mechanical properties of steel: High Strength Elasticity Ductility Toughness CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 10 10 5  Steel Steel is an alloy in which iron (main substance) is mixed with carbon (0.1% to 1.7%) and other substances (manganese, silicon, etc.). Iron with very low amount of carbon (2%)is referred to cast iron that is extremely brittle but strong. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 11 11 Steel Semi-finished product (slabs, billets, blooms) are re- heated at about 1200 oC, red hot and shaped by rolling that is called hot-rolling process (the melting temperature of steel is about 1400 oC). Most structural steel shapes are hot-rolling. Thin sheets of carbon steel (0.3%-1.7%), that are bent to desired shapes, are called cold-formed steel shapes. Source: Steelconstruction.info CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 12 12 6  Soil & Aggregates Soil may be classified as boulders, cobbles, gravel, sand, silt, clay, and peat. Aggregate, a mass of crushed stone, gravel, sand, etc., are used as underlying material for pavements and foundations, ingredients in cement concrete and asphalt concrete, and riprap for erosion protection. For most applications, aggregates must be angular rather than rounded. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 13 13 Portland Cement Portland cement is primarily used to make concrete but also stabilizes soils and aggregates in highway construction. Patented by Joseph Aspdin in 1824, it was named after the limestone cliffs on England's Isle of Portland. Its production requires two main raw ingredients: a calcareous material (limestone, chalk, or oyster shells) and an argillaceous material (clay, shale, or blast furnace slag). CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 14 14 7  Portland Cement Type I - Ordinary Portland Cement (OPC): Used for general constructions. Type II - Moderate Sulfate Resistance: Used for constructions exposed to moderate levels of sulfate in soil or groundwater, such as in wastewater treatment plants, drainage structures, and certain foundations. Type III - High Early Strength: Used for projects needing quick strength gain, such as in precast or prestressed concrete and in repairs or constructions requiring quick turnover. Type IV - Low Heat of Hydration: Used for large concrete structures like dams, which generate significant internal heat during setting massive concrete. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 15 15 Portland Cement Type V - High Sulfate Resistance: Used in environments with high sulfate content, such as certain soils, seawater, and industrial waste zones. White Portland Cement: Used for decorative applications like terrazzo floors, architectural facades, and tile grouts. Its properties are similar to Type I. Blended Portland Cement: Blended with other materials like slag, fly ash, or silica fume, enhancing workability, durability, and sulfate resistance. It also reduces the overall environmental impact due to lower clinker content. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 16 16 8  Concrete Concrete = Portland Cement + Aggregates (Course & Fine) + Water Mortar = Portland Cement + Fine Aggregates + Water Paste = Portland Cement + Water CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 17 17 Concrete There are many types of cements. But Portland Cement (simply cement) is extremely widespread. Cement clinker: Limestone (or chalk) and clay (or furnace slag) are mixed and heated to melt (2500 – 3000 oF ≡ 1400 – 1650 oC). Cement: gypsum is added to cement clinker and powdered. Very small particles of cement (1 to 2 x 10 12 particles/kg) produce a large surface area, creating more hydration when mixed with water. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 18 18 9  Concrete 60-75% of volume of concrete is occupied by aggregates (80-85% of weight); Aggregates consist of sand and gravels. The ratio of cement, water, and aggregate in a concrete mix significantly affects its properties; for instance, a higher cement-to-aggregate ratio increases strength, while a higher water-to-cement ratio improves workability but may reduce durability. Common mix ratios are adjusted based on the structural requirements and specific application. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 19 19 Concrete Despite its low tensile strength, concrete offers excellent compressive strength, durability, and resistance to fire and weathering, making it an ideal material for various structural applications. In reinforced concrete elements, steel bars (rebar) are embedded within the concrete to handle tensile forces, while the concrete efficiently bears the compressive loads, creating a strong, balanced structural system. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 20 20 10  Masonry Masonry is one of the oldest building methods, dating back thousands of years. Iconic structures like the Egyptian Pyramids, the Great Wall of China, and ancient Persian, Roman, and Greek ruins showcase its durability and lasting appeal. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 21 21 Masonry In modern construction, masonry materials are used not only for structural stability but also for their aesthetic qualities in facades, decorative walls, and landscaping elements. Masonry materials are known for their fire resistance, sound insulation, and thermal mass, making them ideal for sustainable building practices and energy-efficient designs. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 22 22 11  Masonry Blocks Types of masonry blocks: Hollow concrete blocks Solid concrete blocks Clay bricks (solid) Stone (solid) Structural clay tiles (hollow) CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 23 23 Masonry - Mortar Mortar serves as the bonding agent between masonry units, distributing loads and accommodating slight movements. Its properties significantly impact the durability and stability of masonry structures. Mortar used in masonry structures are: Cement mortar (cement + sand + water) Cement-lime mortar (cement +lime + sand + water) Etc. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 24 24 12  Masonry - Mortar Mortars are used for bonding the masonry units together sealing, filling, and leveling the units creating a seating for units plastering grouting etc. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 25 25 Wood Wood is the easiest construction material can be used where it is available. Low cost and easy to use Durable Low weight Relatively high strength CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 26 26 13  Wood Tensile strength of wood is greater than its compressive strength. Its tensile strength perpendicular to its grain is negligible. Natural wood and engineered wood products are used extensively for buildings, bridges, utility poles, floors, roofs, trusses, and piles. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 27 27 Types of Main Structural Wood 1. Dimension Lumber: standardized, smaller cross-sectional lumber (e.g., 2x4, 2x6) sawn on all four sides and used for studs, sill and top plates, joists, beams, rafters, trusses, and decking. 2. Heavy Timber: Large-dimension wood (usually 4x6 or larger) used for heavy frame construction, landscaping, railroad ties, and marine construction. It is valued for its structural strength and fire resistance. 3. Round Stock: They are used for building poles, marine piling, and utility poles. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 28 28 14  Types of Main Structural Wood 4. Engineered Wood: Man-made wood products (like plywood, glulam, and laminated veneer lumber−LVL) created by bonding wood strands, fibers, or veneers to enhance strength and dimensional stability. Glulam (Glued Laminated Timber) is made by gluing layers of lumber together, offering high strength and flexibility for large-span beams. Veneers are thin layers or slices of wood that are typically less than 3 mm (1/8 inch) thick. CIVI 212 - © Dr. R. Tadayon, 2024. All rights reserved. 29 29 15