Lesson 09 Construction Materials PDF

MATERIAL SCIENCE AND ENGINEERING WOOD CONCRETE ASPHALT IN COLLABORATION OF BSEE 4-2 AND BSEE 4-4 CONSTRUCTION MATERIALS GROUP 9 BSEE 4-2 DEL VALLE, BRENT ULYSSES MALIMBAN,...

MATERIAL SCIENCE AND ENGINEERING WOOD CONCRETE ASPHALT IN COLLABORATION OF BSEE 4-2 AND BSEE 4-4 CONSTRUCTION MATERIALS GROUP 9 BSEE 4-2 DEL VALLE, BRENT ULYSSES MALIMBAN, RENALYN BSEE 4-4 PASCUAL, RHOLAN JAMES CATALUÑA, CHRISTIAN JEREMY THE STRUCTURE OF WOOD Introduction to Wood Wood is a hard, fibrous structural tissue found in the stems and roots of trees and other woody plants. In addition, wood is a strong, lightweight material that still dominates much of the construction industry. It is consider that wood is a complex fiber-reinforced composite composed of long, unidirectionally aligned, tubular polymer cells in a polymer matrix. THE STRUCTURE OF WOOD  The Constituents of Wood In general, wood contains cellulose, hemicellulose, lignin, and extractives. It makes up 40% to 50% of the wood. It is the It makes up 25% to 35% of the wood. It is the core structural component that provides flexible filler that interconnects cellulose fibers that strength and rigidity to wood. It has degree of contributes to the overall structural integrity of the polymerization of about 10,000.. wood. It has degree of polymerization of about 200. It makes up 20% to 30% of the wood. It is the hard substance filling spaces in wood cell walls that adhere cellulose and hemicellulose altogether in which adds toughness and making wood more water-resistant. The basic component of wood is cellulose, arranged in polymer chains that form long fibers. In addition, It makes at most 10% of the wood. It is the cellulose is a thermoplastic biopolymer build up on collection of organic compounds including oils and repeating units of glucose. resins, that shield wood from pests and help it endure environmental stress. THE STRUCTURE OF WOOD  The Structure of Wood There are three important levels in the structure of wood which are the fiber structure, the cell structure, and the macrostructure. THE STRUCTURE OF WOOD  The Fiber Structure of Wood In the structure of wood, the lignin, hemicellulose, and cellulose are arranged in a layered, interconnected structure, each playing a distinct role in strength and flexibility. The entire bundle, consisting of cellulose chains, hemicellulose chains, and lignin, is called a microfibril; it can have a virtually infinite length. LIGNIN CELLULOSE HEMICELLULOSE THE STRUCTURE OF WOOD  The Cell Structure of Wood LUMEN The tree is composed of elongated cells, often INNER SECONDARY WALL having an aspect ratio of 100 or more, that constitute about 95% of the solid material in MIDDLE SECONDARY WALL wood. The hollow cells are composed of several layers of walls built up from the microfibrils. OUTER SECONDARY WALL The major parts of a wood cell include the lumen, middle lamella, primary wall, and PRIMARY WALL secondary wall. The lumen is the central hollow part of the cell that once carried water and nutrients. The middle lamella is the outer layer that glues cells together. The primary wall is a MIDDLE LAMELLA thin, flexible layer that allows the cell to grow. The secondary wall is a thick, strong layer that supports the cell’s structure. THE STRUCTURE OF WOOD  The Macrostructure of Wood SAPWOOD The lighter, outer wood layer that actively conducts PHLOEM water and minerals from roots to leaves. A layer under the bark that transports sugars and nutrients from the leaves to other parts of the tree. HEARTWOOD The dense, inner core of the tree that provides structural support and is resistant to decay. BARK The outer protective layer of a tree that shields it from physical damage, pests, and environmental elements. PITH The central core of the stem, essential for nutrient transport in a young tree, which becomes less CAMBIUM active as the tree matures. A thin, growing layer between bark and wood that produces new cells, allowing the tree to grow in diameter THE STRUCTURE OF WOOD  Earlywood and Latewood YOU KNOW? DID Did you know that a tree's age can be LATEWOOD estimated by counting its rings? Each ring It is also known as summerwood, and it is the represents one year of growth, with wider denser and darker portion of the wood. It is rings indicating favorable conditions like produced later in the growing season. ample rain and sunlight, and narrower rings showing periods of drought or limited resources. By studying these rings, scientists can learn not only the tree's age but also historical climate patterns, giving insights into environmental changes over centuries! This EARLYWOOD science, known as dendrochronology. It is also known as springwood, and it is less dense and has a lighter appearance as compared to latewood. It is produced the beginning of the growing season. THE STRUCTURE OF WOOD  Hardwood Versus Softwood Hardwood Softwood They come from deciduous trees, such They come from coniferous or needle- as oak. Hardwoods are usually denser, leaved trees. Softwoods are usually less stronger, and more scratch-resistant. dense and hard-wearing. Oak Pine Hickory Spruce Elm Hemlock Birch Fir Walnut Cedar THE STRUCTURE OF WOOD  The Cellular Structure Comparison of Hardwood and Softwood In hardwood, the elongated cells are relatively short, with a In softwoods, the cells tend to be somewhat longer than in diameter of less than a tenth of a millimeter and a length of the hardwoods. The hollow center of the cells is responsible less than one millimeter. Contained within the wood are for transporting water. In general, the density of softwoods longitudinal pores, or vessels, which carry water through the tends to be lower than that of hardwoods because of a tree. greater percentage of void space. THE STRUCTURE OF WOOD  The Cellular Structure Comparison of Hardwood and Softwood THE STRUCTURE OF WOOD MOISTURE CONTENT AND DENSITY OF WOOD  The material making up the individual cells in virtually all woods has essentially the same density —about 1.45 g/cm³; however, wood contains void space that causes the actual density to be much lower. The density of the wood depends primarily on the species of the tree (or the amount of void space peculiar to that species) and the percentage of water in the wood (which depends on the amount of drying and on the relative humidity to which the wood is exposed during use). Completely dry wood varies in density from about 0.3 to 0.8 g cm³, with hardwoods having higher densities than softwoods. The measured density is normally higher due to the water Density of a Wood contained in the wood. MOISTURE CONTENT AND DENSITY OF WOOD  Percentage Water Content in Wood The percentage water is given by: It is possible to describe a wood as containing more than 100% water. The water is contained both in the hollow cells or vessels, where it is not tightly held, and in the cellulose structure in the cell walls, where it is more tightly bonded to the cellulose fibers. MOISTURE CONTENT AND DENSITY OF WOOD  Table of Properties of Typical Woods The density and modulus of elasticity parallel to the grain of several common woods are included in this table for this typical water content. MOISTURE CONTENT AND DENSITY OF WOOD  MECHANICAL PROPERTIES OF WOOD Mechanical Properties of Wood Wood Strength depends on its density, which in turn depends on moisture content, and type of wood. The effect of the percentage of water in a typical wood on the compressive strength parallel to the grain As moisture decreases, wood strength remains stable until reaching the fiber saturation point (around 30%), after which further drying significantly increases compressive strength. MECHANICAL PROPERTIES OF WOOD  Mechanical Properties of Wood The mechanical properties of wood are highly anisotropic. Anisotropic behavior refers to the property of a material where its physical characteristics, such as strength, expansion, or conductivity, vary depending on the direction in which they are measured. The different directions in a log cause wood to exhibit anisotropic behavior due to variations in cell orientation and grain structure. Wood is anisotropic because its fibers are aligned differently in various directions, making it stronger along the grain and MECHANICAL PROPERTIES OF WOOD weaker across it.  Mechanical Properties of Wood The mechanical properties of wood are highly anisotropic. PLAIN SAWN LUMBER QUARTER-SAWN LUMBER MECHANICAL PROPERTIES OF WOOD  Table of Anisotropic behavior of several woods (at 12% moisture) Strength data showcasing the variation in tensile and radial strengths of different wood species at 12% moisture, which illustrates the directional differences in wood performance. MECHANICAL PROPERTIES OF WOOD  Table of Comparison of the specific strength and specific modulus of wood with those of other common construction materials This highlights wood’s efficiency in strength-to-weight ratio compared to metals and composites MECHANICAL PROPERTIES OF WOOD EXPANSION AND CONTRACTION OF WOOD  Why Wood Expands and Contracts Wood expands and contracts with changes in surrounding humidity and, to a lesser degree, temperature. This movement is often referred to as hygroscopic behavior. Anisotropic Nature The degree of expansion and contraction Hygroscopic Nature varies depending on the direction of the wood's grain: When the relative humidity increases, wood absorbs moisture, causing it to Tangential (across the growth rings) swell (expand) as the water penetrates expansion is the greatest. the wood’s cell walls. Conversely, when Radial (perpendicular to the growth rings) the air is dry, wood releases moisture expansion is less than tangential and shrinks (contract). Longitudinal (along the grain) expansion is minimal EXPANSION AND CONTRACTION OF WOOD  Table of Dimensional Coefficients c (in./ in.% H2O) for several woods Formula for Dimensional Change: Δx = x₀ [c(Mₓ - Mᵢ)] Where x₀ is the initial dimension, c is a dimensional coefficient, and M is moisture content. EXPANSION AND CONTRACTION OF WOOD PLYWOOD  Introduction to Plywood Ordinary wood is prone to cracking because it is highly sensitive to changes in moisture content. Wood fibers expand and contract as they absorb or lose too much moisture from the air. In addition, woods are anisotropic, in which contributes to uneven stress within the wood fibers. The anisotropic behavior of wood can be reduced and wood products can be made in larger sizes by producing plywood. It is an engineered wood material manufactured by gluing together thin sheets of wood, called veneers or plies, with the grain of the layers typically arranged PLYWOOD at wide or perpendicular angles for strength.  How Plywood is Created PLYWOOD  Other Types of Engineered Wood PARTICLE BOARDS FIBREWOOD It is a type of engineered wood made from wood It is a type of engineered wood composite made up chips, sawmill shavings, or sawdust, bound of fine wood fibres that will mix with resin binders together with resin and pressed into sheets. and wax. PLYWOOD CONCRETE MATERIALS  Concrete Materials Aggregate: A combination of gravel, sand, crushed stones, or slag used in concrete. Mortar: Made by mixing cement, water, air, and fine aggregate; it serves as a bonding agent for masonry. Concrete: Contains all components of mortar plus coarse aggregates, forming a strong building material. Cement: inorganic material that sets and hardens when mixed with water. CONCRETE MATERIALS  Concrete Materials Concrete is a particulate composite where both the aggregates and the cement matrix are ceramic materials. Sand and coarse aggregates are bonded in a matrix of Portland cement. When water is added to the cement, a hydration reaction occurs, producing a solid gel that bonds the aggregate particles After hydration, the cement provides the bond for the aggregate particles. CONCRETE MATERIALS  Types of Cement Hydraulic Cement: Sets and Non-Hydraulic Cement: Requires hardens under water air to harden Example: Portland cement Example: Lime (CaO) CONCRETE MATERIALS  Rate of Hydration The types and amounts of minerals in cement affect how it hardens (cures) and the concrete’s final properties. 3CaO + SiO₂ (Tricalcium Silicate, C₃S) - Reacts quickly with water. Major contributor to early strength in concrete. 2CaO + SiO₂ (Dicalcium Silicate, C₂S) - Reacts more slowly. Provides long-term strength over time. 3CaO + Al₂O₃ (Tricalcium Aluminate, C₃A) - Reacts very rapidly, producing heat. Gypsum is added to control its reaction, preventing overly quick setting. CONCRETE MATERIALS  Curing of Concrete Concrete continue to gain strength as it hydrates. After 28 days, concrete approaches its maximum strength In ideal conditions, concrete may continue to gain strength beyond 28 days, reaching its full potential over time. CONCRETE MATERIALS  Types of Portland Cement CONCRETE MATERIALS  Sand predominantly composed of silica (SiO2). sand particles typically range from 0.1 to 1.0 mm in diameter often contains absorbed water which is taken into account when preparing concrete mix. Function of Sand Help fills void between coarsed aggregates Minimize open porosity in finished concrete Reduce disintegration due to repeated freezing and thawing during service CONCRETE MATERIALS CONCRETE MATERIALS  Coarse Aggregates primarily composed of gravel, crushed stones, or rock. aggregates must be clean, strong, and durable to ensure effective bonding with cement. Shape and Size angular particles provide mechanical interlocking between particles and provide more surface on which void and cracks may form. the size of aggregate should not exceed about 20% of thickness of the structure being produced to prevent structural weaknesses. CONCRETE MATERIALS  Special Aggregates Lightweight Aggregates Heavy Aggregates made from materials like expanded composed of dense minerals or metal clay or mineral slags that improve shot used for application requiring thermal insulation properties. radiation shielding such as nuclear reactors. CONCRETE MATERIALS PROPERTIES OF CONCRETE  Factors that Influence Properties of Concrete Water-Cement Ratio Air-Entrained Concrete Type and Amount of Aggregate PROPERTIES OF CONCRETE PROPERTIES OF CONCRETE  Water-to-Concrete Ratio The slump test, in which deformation of a concrete shape under its own weight is measured. Slump - The decrease in height of a standard concrete form when the concrete settles under its own weight. This describes the workability of concrete. Ideal slump is 4 inches. It gives an indication of the concrete's flowability and is particularly helpful in assessing if the water content is appropriate, as this influences the concrete’s strength, durability, and ease of placement. A minimum water– cement ratio of about 0.4 (by weight) is usually required for workability PROPERTIES OF CONCRETE  Types of Slump True - the concrete largely retains its cone shape, demonstrating that the mix is cohesive and its workability isn’t too high. Zero - the concrete retains its shape completely. This shows that the mix is very dry (this kind of concrete is best used in road construction). Collapsed - the mix doesn’t retain its shape at all and completely collapses. This means the water-cement ratio is too high and needs to be fully amended. Shear - the top half of the concrete subsides dramatically, leaning to one side, meaning the mix has workability but low cohesion. PROPERTIES OF CONCRETE  Air-Entrained Concrete A small amount of air is typically trapped in the concrete during pouring. For coarse aggregates, like 1.5-inch rock, around 1% of the concrete's volume may consist of air. With finer aggregates, such as 0.5- inch gravel, up to 2.5% air may be retained. In some cases, we deliberately introduce air into concrete—up to 8% when using fine gravel. This entrained air enhances the concrete’s workability and helps reduce issues related to shrinkage and freeze–thaw cycles. However, air-entrained concrete generally has lower strength. The effect of the water-cement ratio and entrained air on the 28-day compressive strength of concrete PROPERTIES OF CONCRETE  Type and Amount of Aggregates There are 2 main types of Aggregates: coarse and fine. The amount of water per cubic yard of concrete The volume ratio of aggregate to required to give the desired workability (or slump) concrete depends on the sand and depends on the size of the coarse aggregate. aggregate sizes. PROPERTIES OF CONCRETE  REINFORCED AND PRESTRESSED CONCRETE  Reinforced Concrete Steel rods (known as rebar), wires, or mesh are frequently introduced into concrete to provide improvement in resisting tensile and bending forces. The tensile stresses are transferred from the concrete to the steel. Polymer fibers, which are less likely to corrode, also can be used as reinforcement. PROPERTIES OF CONCRETE  Prestressed and Post-stressed Concrete Prestressed Concrete is where concrete is casted Post-stressed Concrete is an alternate method, around steel bars or cables that are already under after the concrete cures, steel rods or cables tension. The concrete bonds to the steel, and the running through the tubes then can be pulled in tension is transferred to the concrete when the steel tension, acting against the concrete is released. PROPERTIES OF CONCRETE ASPHALT  Asphalt Asphalt is a composite material composed of aggregate and bitumen, a thermoplastic polymer commonly sourced from petroleum. Due to its durable nature, asphalt is widely used in paving and road construction. ASPHALT  Composition of Asphalt Aggregates - Granular material used in construction, consisting of sand, gravel, crushed stone or slug. Bitumen - Viscous, black substance derived from petroleum functioning as binder in asphalt. Additives - Gasoline or kerosene that modify the binder's properties. Aggregates Bitumen Additives ASPHALT  Ideal Structure of Asphalt The aggregates should be clean and angular shape.: Wide range of aggregate Appropriate Binder Content Undesirable Structure Round Grains Narrow Distribution of Grain Sizes Too much binder ASPHALT  Binder and Aggregate Ratios in Asphalt Optimal Binder Ratio 5-10% binder content by volume, with a void space of 2-5% to accommodate pressure without excess surface deformation or loss of bitumen. Effects of Variation in Ratios Excess Binder permits viscous deformation of the asphalt under load. Insufficient Binder results in poor adhesion among aggregates, increasing the risk of cracking and surface failure. Excessive voids allow water infiltration, which can deteriorate the asphalt and embrittle the binder. Less Void Space can trap moisture and prevent proper drainage. ASPHALT  Types of Asphalt Hot Mix Asphalt Warm Mix Asphalt The most commonly used type of Warm Mix Asphalt is created by asphalt, made by heating a mixture of mixing aggregate with asphalt binder aggregate (crushed stone, gravel, and but at lower temperatures, typically sand) and asphalt cement (a around 200-250 degrees Fahrenheit petroleum product) to 300-350°F. ASPHALT  Types of Asphalt Cold Mix Asphalt Cold Mix Asphalt is produced without heating. Instead, the asphalt binder is mixed with aggregate at ambient temperatures, often using a special type of binding agent or emulsion that makes it workable without heating. ASPHALT  Asphalt Emulsions mixtures of liquid asphalt and water. used for sealing driveways and improvingthe longevity of pavements. Innovations in Asphalt Modern asphalt technology incorporates recycled materials like shredded rubber tires and Glasphalt. Glasphalt: crushed recycled glass as aggregate in asphalt mixtures ASPHALT  Reference Book Askeland, D. R., Fulay, P. P., & Wright, W. J. (2010). The Science and Engineering of Materials (6th ed.). Cengage Learning. Websites Identification Of Common North American Woods https://woodidentification.net/terminology-explained/#Top Hardwood vs. Softwood: What Are The Differences? https://duffieldtimber.com/the-workbench/timber-trends/hardwood-vs-softwood-what-are-the-difference# Wood as a Material https://www.britannica.com/science/wood-plant-tissue/Wood-as-a-material How Do You Measure the Age of a Tree? https://www.nist.gov/how-do-you-measure-it/how-do-you-measure-age-tree# What is MDF and Particle Board? https://www.scandihomeph.com/what-is-mdf-and-particle-board/ What Is Meant By ‘Concrete Slump’ & Why Does It Matter? https://www.totalconcrete.co.uk/news/what-is-concrete-slump-and-why-does-it-matter/ THANK YOU.  MATERIAL SCIENCE AND ENGINEERING WOOD CONCRETE ASPHALT IN COLLABORATION OF BSEE 4-2 AND BSEE 4-4 CONSTRUCTION MATERIALS GROUP 9 BSEE 4-2 DEL VALLE, BRENT ULYSSES MALIMBAN, RENALYN BSEE 4-4 PASCUAL, RHOLAN JAMES CATALUÑA, CHRISTIAN JEREMY