Construction Materials PDF

Module Code and Title: PWOPR301 PUBLIC WORK RESOURCES LEARNING OUTCOME 1: DESCRIBE THE CONSTRUCTION MATERIALS USED IN PUBLIC WORKS Indicative content 1.1: DESCRIPTION OF NATURAL CONSTRUCTION MATERIALS  Natural Construction Materials Use Definition: The term 'natural materials' refers to those subs...

Module Code and Title: PWOPR301 PUBLIC WORK RESOURCES LEARNING OUTCOME 1: DESCRIBE THE CONSTRUCTION MATERIALS USED IN PUBLIC WORKS Indicative content 1.1: DESCRIPTION OF NATURAL CONSTRUCTION MATERIALS  Natural Construction Materials Use Definition: The term 'natural materials' refers to those substances that are found in nature and which can either be used directly for some particular building function or require human intervention (e.g processing) to make them usable. Building material is any material used for construction purpose such as materials for house building. Examples of natural building: Soil Aggregates stones water wood Soil description Definition: Soil is directly used to make building materials, such as cement and brick, as well as indirectly used to grow the plants used to make building materials such as wood boards and insulation fibers. Historically, many homes and other structures were made from soil or soil that was caked and dried into blocks. Importance of soil in construction Access to good soil is very important for building a modern infrastructure. Soil is directly used to make building materials, such as cement and brick, as well as indirectly used to grow the plants used to make building materials such as wood boards and insulation fibers. Historically, many homes and other structures were made from soil or soil that was caked and dried into blocks. Since soil is everywhere, all structures are also built on soil. Selection of sites with the best soil is an important engineering decision in the building process. Soil maps are a great tool to help engineers determine the best location for their design.2 Types and properties of aggregates Definition: Aggregates are raw materials that are produced from natural sources and extracted from pits and quarries, including gravel, crushed stone, and sand. When used with a binding medium, like water, cement, and asphalt, they are used to form compound materials, such as asphalt concrete and Portland cement concrete. Types of Aggregates Types of aggregates include Coarse aggregate and fine aggregate. The aggregate of each type is further sub-divided into many types and classification based on its size. Fine aggregates generallys consist of natural sand or crushed stone with most particles passing through a 4.75mm sieve. Coarse aggregates are any particles greater than 4.75mm. Functions of aggregates in construction Aggregate materials help to make concrete. Aggregate materials decrease the consumption of cement and water Aggregate materials contribute to the mechanical strength of the concrete Aggregates contribute to the strength and durability of concrete. Fine aggregates like sand are used in water filtration systems and wastewater treatment to remove impurities and contaminants from water. Properties of aggregates Good-quality aggregate must be: Clean, Hard, Strong, Have durable particles Free of absorbed harmful chemicals Properties of stones in line with their uses Stones form one of the most important building materials in civil engineering. Stones are derived from rocks, which form the earth's crust and have no definite shape or chemical combination but are mixtures of two or more minerals.3 Properties of stone A good building stone should: Have good appearance Be more durable. Be dressed easily. Free from tractor hardness and wear. Be Hard Be Tough Have porosity and absorption percentage within its permissible limit. Workable. Types of stones in line with their uses NO TYPES OF STONE USES OF STONE IN CONSTRUCTION 1 Granite Granites are used in construction work such as steps, walls, kitchen, frames of door and windows. 2 Ballast Ballast is used in foundation work, masonry, road. 3 Chalk Chalk is used in the manufacturing of Portland cement and putty work. 4 Gneisses Gneisses are commonly used in street paving, masonry work, 5 Lime stones Uses of lime stones are many purposes like for flooring, step, wall, manufacture of lime 6 Marbles Marble is used for flooring purposes, steps, facing work 7 Murum Murum is used in the garden wall, for fancy paths 8 kankar It is used in the manufacturing of hydraulic lime 9 Laterite it’s used in stone masonry, building stone and road 10 Slate use of sandstones are for flooring purposes, wall, and carving purposes 11 Quartzite It is used in pitching work, rubble masonry, facing of building and retaining walls4 Properties of water according to its use as a construction material. Definition Water is the clear liquid that has no color, taste, or smell, that falls from clouds as rain, that forms streams, lakes, and seas, and that is used for drinking, washing, etc Water is one of the most important elements in construction but people still ignore quality aspect of this element. The water is required for preparation of mortar, mixing of cement concrete and for curing work. Properties of Water The water used for mixing and curing should be clean. Potable water is generally considered satisfactory for mixing. The pH value of water should be not less than 6. Universal Solvent Effects of water in construction Presence of impurities in water for concrete mix leads to decrease in structural properties of concrete such as strength and durability to a large extent. The effect of water impurities on properties of concrete can be expressed mainly in two terms: In terms of the difference in the setting times of the Portland cement mixes that consist of proposed mixing water when compared with the use of distilled water. In terms of the concrete strength that is compared with the control specimens that is prepared with the distilled water. Indicative content 1.2: DESCRIPTION OF BINDING MATERIALS Description of cement Definition A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is used to bind sand and gravel (aggregate) together. Uses of cement Cement is mainly used as a binder in concrete, which is a basic material for all types of construction, including housing, roads, schools, hospitals, dams and ports, as well as for decorative applications (for floors, staircases, driveways, pool decks) and items like tables, sculptures or bookcases5 Types of cement No Types of cement uses 1 Ordinary Portland Cement (OPC) It is widely used for all purposes including: Concrete, Mortar and Plaster 2 Portland Pozzolana Cement (PPC) It is widely used in construction such as: Marine structures, Sewage works, Bridges, Piers, Dams and Mass concrete works 3 Rapid Hardening Cement It is commonly used in rapid constructions like the construction pavement. 4 Extra Rapid Hardening Cement Extra rapid hardening cement is widely used in cold weather concreting, to set the cement fast. Eg. concreting in water. 5 Low Heat Cement This low heat cement is used in mass concrete construction like gravity dams. 6 Sulfates Resisting Cement It can be used in concrete surfaces subjected to salts, to alternate wetting and drying like bridge piers. 7 Quick Setting Cement Quick setting cement is used for constructions that need a quick setting, like underwater structures and in cold and rainy weather conditions. 8 Blast Furnace Slag Cement It is used for constructions where economic considerations are important. 9 High Alumina Cement The most common uses are in constructions that are subject to high temperatures like a workshop, refractory, and foundries( casting metal). 10 White Cement It is similar to OPC but it is more expensive. Properties of good cement. It is always desirable to use the best cement in constructions. Provides strength to masonry. Stiffens or hardens early. Possesses good plasticity. An excellent building material. Easily workable. Good moisture-resistant.6 Description of lime Definition The word “lime” refers to products derived from heating limestone. It originates with its earliest use as building mortar and has the sense of “sticking or adhering“. Uses of lime In construction, the dominant use of lime is in soil stabilization for roads, earthen dams, airfields, and building foundations. Lime can be combined with certain additives to produce other metals and is also a key ingredient in mortar and plaster in lime slurry form. As an additive in asphalt, lime improves its cohesion, reduces stripping, and retards the aging process. Properties of Lime Good lime should have the following qualities : It should possess good plasticity It should be flexible and easily workable When used in mortar, it should provide greater strength to the masonry. It should solidify in less time and become hard. It should compare at excellent binding properties which adhere to brick or stone masonry units perfectly. It possesses high durable properties as it is less shrinkable when used in mortar. It should be highly resistant to moisture and can be used for pointing works. Bitumen description Definition. Bitumen is a black viscous mixture of hydrocarbons obtained naturally or as a residue from petroleum distillation or purification. We will discuss the properties of Bitumen in this article. Uses of bitumen Bitumen is used to construct roads, roofs, dams, etc. It is highly adhesive and used to bind two or more materials together. 7 Types of bitumen The bitumen can be classified into the following grade types: Penetration Grade Bitumen Oxidized Bitumen Grades Cut Back Bitumen Bitumen Emulsion Polymer Modified Bitumen Properties of Bitumen Bitumen should have the following desirable properties : Highly adhesive in nature. Highly resistive to water. Sufficient strength Highly durable and versatile Minimum loss of heating Resistive towards chemicals Lower temperature susceptibility Economical Indicative content 1.3: DESCRIPTION OF IN SITU CONCRETE PRODUCT Concrete composition Definition Concrete is a building material made from a mixture of broken stone or gravel, sand, cement, and water. Concrete composition Concrete is a mixture of cement, air, water, sand, and gravel. The typical concrete mix is made up of roughly 10% cement, 20% air and water, 30% sand, and 40% gravel. This is called the 10-20-30-40 Rule–though proportions may vary depending on the type of cement and other factors. Types of concrete Different types of concrete are: Normal Strength Concrete Plain or Ordinary Concrete Reinforced Concrete Prestressed Concrete Precast Concrete Light – Weight Concrete High-Density Concrete8 Air Entrained Concrete Ready Mix Concrete Polymer Concrete Polymer concrete Polymer cement concrete Polymer impregnated concrete High-Strength Concrete High-Performance Concrete Self - Consolidated Concrete Shotcrete Concrete Pervious Concrete Vacuum Concrete Pumped Concrete Stamped Concrete Limecrete Asphalt Concrete Roller Compacted Concrete Rapid Strength Concrete Glass Concrete Concrete properties Once the mixing was completed the mixture is said to be Fresh concrete which is in plastic state and can be moulded in any forms whereas the Hardened concrete is the one which is fully cured. Properties of Fresh Concrete Concrete is referred to as fresh when the setting and hardening process has not yet started. Fresh concrete can be deformed and poured which means it can be transported or pumped and used to fill moulds and formwork. Workability Segregation Bleeding Plastic shrinkage Setting Temperature Water Cement Ratio Hydration Properties of Hardened Concrete Hardened concrete is a type of concrete that is strong and have the capacity to bear the structural as well as service loads that are applied to it. There are various properties of hardened concrete which are as follows: 9 Properties of Hardened Concrete Strength Impermeability Durability Dimensional Changes Shrinkage Concrete production steps Batching.: For good quality concrete a proper and accurate quantity of all the ingredients should be used. The aggregates, cement and water should be measured with an accuracy of 3 per cent of batch quantity and the admixtures by 5 per cent of the batch quantity. There are two prevalent methods of batching materials are: the volume batching and the weigh batching. Mixing: The "complete blending of the materials which are required for the production of a homogeneous concrete. This can vary from hand to machine mixing, with machine mixing being the most common. Transporting: Concrete should be transported to the place of deposition at the earliest without the loss of homogeneity obtained at the time of mixing. A maximum of 2 hours from the time of mixing is permitted if trucks with agitator and 1 hour if trucks without agitators are used for transporting concrete. Placing: To achieve quality concrete, it should be placed with utmost care securing the homogeneity achieved during mixing and the avoidance of segregation in transporting. Compacting: The process which expels entrapped air from freshly placed concrete and packs the aggregate particles together so as to increase the density of concrete. It increases significantly the ultimate strength of concrete and enhances the bond with reinforcement. Curing: After concrete is placed at the desired location, the next step in the process of concrete production is its compaction. Compaction consolidates fresh concrete within the moulds or frameworks and around embedded parts and reinforcement steel.10 Finishing: Concrete is basically used because of its high compressive strength. However, the finish of the ultimate product is not that pleasant. In past couple of decades efforts have been made to develop surface finishes to give a better appearance to concrete surfaces Concrete curing methods The curing of concrete is the process of keeping the concrete damp or moist and warm after the initial setting of concrete or removal of formwork. Proper curing of concrete maintains the satisfactory moisture content and favorable temperature inside the concrete so that hydration of cement may continue until the desired properties are developed. The curing of concrete must be continued for a reasonable period of time to achieve its desire strength and durability. Methods of Curing Concrete 1. Water Curing Method Water curing method is most general methods of curing as it satisfies all the requirements of curing. These methods maintain the presence of moisture in the concrete during the early hardening period. Water curing can be done in the following types: (a) Immersion Method: This is the best water curing method. In immersion method, finished concrete is immersed in the curing tank or curing pond. (b) Ponding Method: In the ponding method, small rectangular or square artificial ponds are built with using bunds of clay or lean mortar or sand across and along the concrete surface. Water is filled in small rectangular or square ponds two or three times per day depending upon the atmospheric conditions. (c) Spraying or Fogging Method: Curing by spraying of water or fogging is one of the conventional methods of curing concrete in the construction industry. It can be an efficient method for curing by supplying additional moisture during hot weather. By using nozzles or sprayers, water is sprayed on the concrete members, which are to be cured. 11 2. Membrane Curing of Concrete These methods prevent the loss of mixing water from the surface of the concrete. Therefore, membrane curing of concrete can be done in the following types: (a) Wet Covering or Moist Curing Concrete Method: In moist curing concrete method, water absorbent fabrics are used to maintain moisture on the concrete surface by completely covering the surface immediately after the concrete has hardened sufficiently. Generally jute bags, cotton mats, hussian cloth, etc. are used as a covering. (b) Plastic Sheeting: Concrete could be effectively covered with a plastic sheet so that it seals the evaporation of water from concrete. (c) Concrete Curing Compounds: Concrete curing compounds form a thin liquid membrane on the concrete surfaces and result in prevention to a certain extent of evaporation losses. 3. Application of Heat (Steam Curing) In steam curing, strength gain of concrete is accelerated, by supplying heat and additional moisture to the concrete. When concrete is subjected to higher temperature, it accelerates the hydration process and hence resulting in faster development of strength. The types of steam curing methods of concrete are as follows: (a) Steam Curing at Ordinary Pressure: Steam curing at ordinary pressure is generally done in an enclosed room to minimize heat losses and moisture. (b) Steam Curing at High Pressure: This method is something different from ordinary steam curing. In this method, curing is carried out in a closed chamber and superheated steam at high temperature and high pressure is applied on the concrete.12 Indicative content 1.4: DESCRIPTION OF FABRICATED CONSTRUCTION MATERIALS Manufacturing of bricks Definition Brick is a commonly used building material. It is a unit made of burnt clay. Then a dry Brick is made up. Standard Brick Dimensions Besides any other various dimension of bricks, the global construction agencies maintain a standard dimension of brick. Standard brick size for working purpose is 225 x 112.5 x 75 in mm dimension (length x depth x height). In addition, this includes 10 mm mortar joints, and then the actual dimension of brick is 215 x 102.5 x 65 in mm dimension. Besides these different countries uses a different standard dimension of brick. Like The United Kingdom Standard Brick Dimensions The standard dimension of a modern brick is 215 × 102.5 × 65 in mm (length x depth x height) dimension. The United States Standard Brick Dimensions modern standard brick dimension 203 × 92 × 57 mm. The more commonly used is the modular brick, which dimension is 194 × 92 × 57 mm (length x depth x height). India Standard Brick Dimensions The standard brick dimension is 190 x 90 x 90 mm (length x depth x height) as prescribed by BIS. With mortar thickness, the dimension of the brick remains 200 x 100 x 100 mm. Phases of Manufacturing bricks Mining and storage of raw materials, Preparing raw materials, Forming the brick, Drying, Firing and cooling De-hacking and storing finished products13 Timber Identification Definition Timber is a type of wood which has been processed into beams and planks. Timber is used for building houses as beams, columns and plates in construction in a variety of situations, such as foundation, flooring, stairs, concrete formworks and roofing. Types of timber available on the Rwandan market: 14 About 95 per cent of the local supply of sawn wood (timber cut from logs into different shapes and sizes) consists of four species - Eucalyptus, Pinus, Grevillea and Cypress. Imported timber species on the Rwandan market mainly include Libuyu or Mahogany, Muvura or Iroko (Milicia excelsa, or M. regia) and Umusave (Markhamia lutea) imported from DR Congo and Uganda according to a recent study. Types of fabricated concrete products Different types of precast products have varied applications. Depending on the shape, size, and grade of concrete used, its function varies. These products are being used in many construction projects wherein uniformity and control are required. Given below are different types of precast concrete products available: Precast concrete footings Precast concrete piles Precast concrete beams Precast concrete slabs Precast concrete walls Precast concrete roofs Precast concrete box culverts Precast concrete façade Precast concrete glass fiber Precast concrete water drain Precast concrete staircase Precast concrete toilets 15 Identification of metals Metals are solid material that are generally hard, shiny, malleable, fusible, ductile, and have good electrical and thermal conductivity. Metals are commonly used in the construction industry due to their durability and strength to form structural components, pipework, cladding mate rials and other components. Types of metals used in construction Steel. Aluminium Iron Copper Lead Brass. Bronze. Gold. Nickel. Tin. Titanium. Zinc. Applications of metals in construction Due to their intrinsic properties, metals are widely used in the building and construction sector. They are a first choice material for structures, reinforcements, cladding, roofing, window frames, plumbing, heating equipment and many other applications. 16 Indicative content 1.5: DESCRIPTION OF SYNTHETIC CONSTRUCTION MATERIALS. Glasses description Definition It is most typically used as transparent glazing material in the building envelope, including windows in the external walls. Glass is also used for internal partitions and as an architectural feature. Types of glass used in construction. Choosing the right kind of glass for a certain application is crucial to achieving a finished job that’s effective, attractive, and safe. The following are 14 types of glass used in construction: Sheet Glass Float Glass Laminated Glass Shatterproof Glass Energy-efficient Glass Extra-clean / Self-cleaning Glass Chromatic Glass Patterned Glass Tinted Glass Toughened Glass Wired Glass Glass Blocks Glass Wool Insulated Glazed Units Mirrors17 Remark: Float glass, also known as soda-lime glass, is the most widely used type of glass in construction. Float glass is considered by most to be of better visual quality and easier to transport and fabricate than sheet manufactured glass. The float process also allows for much larger sizes for thinner glass products Engineering properties of Glass: Transparency: this is the primary property of glass that allows us to see through it. Glass can be transparent from both sides or from one side only (the other side acts like a mirror). Workability and Recycle Property: glass has superior workability as it can be moulded into countless shapes or blown during melting. Also, any type of glass can be 100% recyclable and used as a raw material in construction. Strength: the strength of glass is determined by its modulus of rupture value. Glass is usually brittle but we can make it stronger by adding admixtures and laminates. Transmittance: this is the visible fraction of light passing through the glass. U value: this represents how much heat transferred through the glass. Insulated glass units should have a low U value18 Plastics material description Definition 'Plastic' is a general name given to a wide range of synthetic materials that are based on polymers. The construction industry uses plastic for a wide range of applications because of its versatility, strength-to-weight ratio, durability, corrosion resistance, and so on. Used plastic for in construction The most common plastics used in construction are polyvinyl chloride (PVC), high density polyethylene (HDPE), and expanded polystyrene (EPS). Plastic is used for various applications such as seals, windows and doors, pipes, cables, floor coverings, and insulation. 19 Identification of Paints Definition Paints are coatings of fluid materials which are applied as a final finish to surfaces like walls, ceiling, wood and metal works. Purpose of paint in building The reasons to use paint in construction include visual appeal, surface durability, chemical protection and pest protection.