Construction Materials I Lecture Notes PDF

Addis Ababa University EiABC Construction Materials I By: Seniya Elias 11/6/2024 1 1. Introduction - Materials - Types of Materials - Definition of Terms 11/6/2024 2 1.Introduction Definition Material: a substance or thing from which s...

Addis Ababa University EiABC Construction Materials I By: Seniya Elias 11/6/2024 1 1. Introduction - Materials - Types of Materials - Definition of Terms 11/6/2024 2 1.Introduction Definition Material: a substance or thing from which some thing else can be made. Examples: Cement, brick, aluminium, soil, water… InEngineering, materials are employed to design and build structures or elements. MaterialEngineering refers to the understanding and review of properties and uses of materials commonly used in engineering.  Material Types ctd Amorphous Materials: Materials in which atoms are arranged randomly/materials with no particular structure. The atoms or molecules of amorphous materials are arranged in essentially the same manner as they are in a liquid. or those that do not have crystalline structure Are strong but brittle Examples: glass, plastics Crystalline materials can be converted in to an amorphous material by quenching. QUENCHING:-heating the material to its melting temperature followed by rapid cooling so that the material has no time to return to its crystalline arrangement Crystalline materials: Materials in which atoms are arranged in a visible repeated pattern in three dimensions. Examples: Sodium chloride Material Types ctd 11/6/2024 5  Material Types ctd Thermoplastic Materials: Materials that turn plastic (soft)when subjected to heat. e.g. petroleum pitch Thermosetting plastic Materials: Materials which strengthen when subjected to heat. e.g. PVC (Polyvinyl Chloride) Brittle Materials: Brittleness denotes relatively little or no elongation or increase in length at fracture. Examples: cast iron, concrete, glass… Building/Construction Materials: Materials that are used in the building/construction industry such as cement, steel ,brick ,plastics, wood, glass, soil,aggregates,asphalt, etc. Aggregates HCB(Hollow Concrete Blocks) 11/6/2024 7 Building/Construction Materials ctd Bricks Timber products 11/6/2024 8 Cementitious materials: Materials in which the principal binder is Portland cement or another type of hydraulic cements. cement Ceramic Materials: The word ceramic comes from Greek, meaning “burned earth” Are nonmetallic materials based on clay content (silicate mineral). - Hence the clay content exceeds 20 percent. Are usually crystalline and brittle, Do not conduct electricity very well, Can withstand high temperatures. 11/6/2024 9 Floor and wall Ceramic materials 11/6/2024 10 Ductile Materials:  Ductility is the property that makes the material to be drawn out or stretched to a considerable extent before rupture.  It is usually measured as the percentage of elongation (increase in length) or as the percentage of the reduction in the cross- sectional area ,when the material is subjected to tension.  Examples :steel ,aluminum etc 11/6/2024 11  Elastic Materials:  Elasticity is the ability of a material to deform under load without a permanent set or deformation up on release of the load.  It can also be defined as that property of material by virtue of which deformations from the a load or stress disappear after removal of the load.  A perfectly elastic material recover completely its original shape and dimensions when loads are removed.  None of the materials remain perfectly elastic throughout the range of stress leading up to failure.  But all exhibit elastic properties up to some stress level.  An elastic material behaves inelastic ally when the stresses exceeds the elastic limit, beyond which changes in volume, shape are permanent. 11/6/2024 12 Steel-ductile material 11/6/2024 13 Thank you !!! 11/6/2024 14