CONSMAT LEC. Concrete and Metals Only PDF

LEC 2_Concrete  Suitable for work underground, in water, or in humid environments. CONCRETE - a mixture of cement, water, aggregates (like sand and gravel) that hardens over  RAPID HARDENING CE...

LEC 2_Concrete  Suitable for work underground, in water, or in humid environments. CONCRETE - a mixture of cement, water, aggregates (like sand and gravel) that hardens over  RAPID HARDENING CEMENT time to create a solid, strong substance.  Finer ground  Greater strength development at an early stage than OPC COMPONENTS OF A CONCRETE  Often used in prefabricated road work and ٥ Cement concrete construction ٥ Coarse aggregates ٥ Fine aggregates  EXTRA-RAPID HARDENING CEMENT ٥ Water  Sets and becomes durable faster than OPC ٥ Air and RHC ٥ Admixtures  Adding more calcium chloride to RHC ٥ Supplementary cementitious materials  Often used in repairing, for concrete drives,. and paths and steps.  LOW-HEAT CEMENT  Lower heat of hydration and needs less water to mix  High chemical corrosion resistance and wear and rupture resistance  Used in floors, and surfaces, dams, and large footings. TYPES OF CEMENT (and their uses)  ORDINARY PORTLAND CEMENT  SULFATE RESISTING CEMENT  Simply known as PORTLAND CEMENT or  Very low heat of hydration TYPE 1 CEMENT  Gains strength at a slower rate  Made of silicates of alumina and calcium  Reduces the risk of sulfate attack on carbonate concrete  Used for general construction and most  Used in constructing foundation in soil with masonry work. high sulfate content  PORTLAND POZZOLANA CEMENT  QUICK SETTING CEMENT  Ground Pozzolanic Clinker mixed with OPC  Sets faster than OPC, but maintains the  Most resistive to chemical reactions within same strength concrete   Beneficial for time-sensitive projects, such as underwater structures and in chilly and rainy climates.  BLAST FURNACE SLAG CEMENT  Ground clinker with up to 60% slag  Less expensive, but with many same properties as OPC  Used for projects where cost concerns are crucial TYPES OF CONCRETE SLUMP  TRUE SLUMP  HIGH ALUMINA CEMENT → Concrete just subsides shortly and more or  High compressive strength less maintain the mould shape  More flexible and workable than OPC → Concrete mixture is cohesive and has good  Commonly used in constructions that are workability exposed to high temperatures, such as → Good cement-to-water ratio workshops, refractories, and foundries → Most desirable  WHITE CEMENT  ZERO SLUMP  Prepared from raw materials that don’t → The concrete retains its shape completely include iron oxide → Little to no workability  More expensive than other cement types → Best used in road construction  Often used in interior and exterior decorative → Low water-to-cement ratio projects  SHEAR SLUMP → Top half of the concrete subsides dramatically, CONCRETE SLUMP leaning to one side CONCRETE SLUMP TEST → Has workability, but low cohesion → Measures the consistency of a concrete batch to → Too much water see how easily the concrete will flow. → Ensures that the batches of the same concrete  COLLAPSE SLUMP are of constant quality and strength. → doesn’t retain its shape at all and completely collapses → Water-to-cement ratio is too high → Least desirable  AGGREGATES COARSE AGGREGATE  When the aggregate is sieved through 4.75 mm sieve, these are the aggregate that are retained Aggregate  They are the key component in concrete → are the important constituents of the concrete because they give the largest amount of → 60% - 80% of the concrete mix durability and strength → Selected for their durability, strength, and workability → Classification according to size: 1. Fine aggregate 2. Coarse aggregrate FINE AGGREGATE  when aggregate is sieved through a 4.75 mm sieve, these are the aggregate that passed through  Fill the voids in the coarse aggregate and act as a workability agent TESTS ON CONCRETE Compression Strength Test → Done by breaking cylindrical concrete specimens in a compression-testing machine → Results can be used for quality control, acceptance of concrete, strength estimation, etc. Flexural Strength Test → Evaluates the tensile strength of concrete indirectly → Tests the ability of unreinforced concrete beam or slab to resist failure in bending → Done to specify compliance with standard, as an essential requirement for concrete mix design, etc. Rebound Hammer WROUGHT IRON PROPERTIES → A non-destructive testing apparatus  weldable at high temperatures and ductile at low → The rebound of the spring-driven mass is temperatures measured after impact  good forming qualities → Output is called rebound number  resistance to corrosion → Assess the in-place uniformity, delineate poor  poor strength quality regions, and an in-place method to test  high melting point concrete strength CAST IRONS → Strength and quality is tested through → A group of iron-carbon alloys, with carbon measuring the velocity of an ultrasonic pulse content greater than 2% passing through the concrete → Got its name because of its excellent casting → Evaluate the dynamic modulus of elasticity, qualities estimate depth of cracks, and detect internal flaws WHERE ARE CAST IRONS USED FOR?  Machines  Automotive parts  Pots and utensils  Anchor for ships LEC4_Metals CAST IRON PROPERTIES  hard and brittle WROUGHT IRONS  low cost → A tough form of iron suitable for forging and  resistance to deformation rolling rather than casting  prone to rusting → Malleable (able to be hammered or pressed  high weight to strength ratio permanently without breaking) WHERE ARE WROUGHT IRONS ARE USED FOR? IRON & PURE IRON  Pipe → Iron is one of the most common elements of the  Bars and railings earth  Iron doors, gates, fences → Pure iron is a soft, grayish – white metal  Plates → Iron is a common element, but pure iron is  Special chains and crane hooks almost never found in nature, it only exist on fallen meteorites  THE ORE EXTRACTION AND REFINING ADVANTAGES OF STEEL PROCESS  High Strength 1. Extraction – iron ores are extracted from open pit  Uniformity mining  Elasticity 2. Refining – mined ores are crushed to remove  Permanence sand and clay away, then refined ores are  Ductility transported to blast Furnace site.  Toughness 3. Manufacturing – ores goes to the blast furnace; carbon monoxide reacts with the iron ore to form METHODS FOR MAKING STEEL carbon dioxide and pure iron. Melted iron sinks to the  OPEN-HEARTH METHOD bottom of the furnace. → the specialty of open hearth is the extreme heat that can be obtained from them due to Mining their regenerative process → Iron ore is generally extracted through open pit mining. The ground is removed from a very large  BASIC OXYGEN METHOD area to expose the one beneath. 1. Blowing of oxygen → The mined one is crushed and sorted by grade 2. Remove sulfur, phosphorus and silicon according to the percentage of iron. 3. Heat process → The refined one is taken from the mining site ti 4. Composition of molten steel the blast furnace where the iron uis melted. 5. Alloying to provide steel properties. Processing  ELECTRONIC FURNACE METHOD → The ore enters the blast furnace from the top as hot air is blown from the bottom. Pure iron forms and sinks to the bottom. → The melted iron is then mold cast into ingots called pigs STEEL FERROUS METALS  Steel Metals that composed of IRONS → basically an alloy of iron and carbon with a Alloy Steel small percentage of other metals such as Carbon Steel nickel, aluminum, tungsten etc. Cast Iron → Steel may not be strong as iron but it is far Wrought Iron more resistant and does not corrode and rust like iron does.  PROPERTIES OF FERROUS METALS → Use extreme care where and how lead is used Ferrous Metals because lead vapors or dust are toxic if ingested. - are highly vulnerable to rusting and corrosion when exposed to moisture or an acidic or corrosive Zinc environment due to high content of carbon molecules. → Is brittle and low in strength - MOST ferrous metals have good magnetic → Major use is in galvanizing (dipping hot iron or properties and are considered to be good conductors steel in molten zinc) of electricity. This property makes them suitable for → May also be used for roofing, flashing, and electronics. hardware NON FERROUS METALS Copper Metals which do NOT contain Iron → Resistant to corrosion, impact, and fatigue; very Aluminum ductile Lead → Primary use is electrical wiring, roofing, flashing, Zinc and piping Copper → The oxidization of copper produces what is Bronze called a green “patina” Brass Bronze Aluminum → Originally a copper-tin alloy, but now aluminum → Highly resistant to weather and corrosive or silicon added to copper environments → Now may be “phosphor bronze”, “aluminum → Aluminum can be economically extruded to bronze” or “silicon bronze” many shapes (mouldings, edgings, window → Widely used for casting delicate mold mullions) impressions (Cathedral doors) → It is very malleable, quite ductile, non-corrosive, and strong in proportion to its weight. Brass → Copper with zinc to form an alloy Lead → Used for doors, windows, railings, trim, grilles → Important physical properties include: resistance and for finish hardware to corrosion, its plasticity, and its malleability → Used for waterproofing, sound and vibration STEEL FRAME CONSTRUCTION isolation, and radiation shield. a) Wide-Flange (W) → Can be combined with a tin alloy to plate iron or  They are commonly used in industrial steel applications. → (called “terneplate”)  They have a straight flange and are most often used in residential construction b) American Standard (S) Two types of testing process:  They have a Sloped flange and are most often 1. Measure depth of penetration used in residential construction  Rockwell hardness test  Brinell Hardness test c) HP-Section (HP)  Vickers Hardness test  These are generally heavier and longer than I-  Meyer Hardness test beams. Appearing like the capital letter ‘H’, they 2. Measure height of rebound have longer flanges.  Scleroscope Hardness test d) Channel (C) NON-DESTRUCTIVE TESTING  Like one half of the S-Section, these have a C- Rockwell Hardness Test shaped cross-section. They are used in → Indicates hardness value by depth that the supporting lighter loads since they are not as penetrator advances into metal under known strong as the other beam shapes. pressure → Designed by various letters and numbers (A, B, e) Angle C, D)  Angle Steel is 'L' shaped; the most common type of Steel Angles are at a 90 degree angle. The Brinell Hardness Test legs of the “L” can be equal or unequal in length. → Indenting the metal surface with a 10-mm diameter steel ball at a load of 3000kg for 30 f) Tee (WT or ST) seconds and the impression is measure by a  WT shapes are cut from a wide flange. ST low-power microscope Standard load of 500kg is shapes are cut from American Standard Beams used for nonferrous metal. → Brinell Hardness Number (BHN) is expressed as TESTING OF METALS the load P divided by a surface area of the Two categories: indentation. 1. NON-DESTRUCTIVE 2. DESTRUCTIVE Meyer Hardness Test → Less sensitive to the applied load than that of NON-DESTRUCTIVE Brinell Hardness - Test performed without breaking the sample → Cold-worked material: relatively constant and independent of load HARDNESS TESTING → Annealed materials: increases continuously with  used to determine hardness of metal load because of strain → capacity to resist wear and deformation  can be used to predict properties and performance of the metal Vickers Hardness Test increases, and the ductility decreases as → Based on an optical measurement system hardness increases → Specifies a range of light loads using diamond indenter → Used for very thin material → Typical Loads : 10 g to 1 kg Scleroscope Hardness Test → The Scleroscope test consists of dropping a diamond tipped hammer, which falls inside a ٥ Proportional Limit - Point the needle stop moving glass tube under the force of its own weight from ٥ Yield Point - Beyond PL and start to stretch a fixed height, onto the test specimen. The ٥ Necking - Reduction in diameter height of the rebound travel of the hammer is ٥ Ultimate Strength - Highest travel of measured on a graduated scale. needle/Maximum pull before breaking ○ Height of rebound is converted to hardness ٥ Breaking Stress reading DESTRUCTIVE - Test performed by breaking the material to determine the quality of material TENSILE TEST IMPACT TEST a. Charpy Test b. Izod Test SAMPLE PROBLEM TORQUE TEST A steel alloy bar 100mm long with a rectangular cross sectional area of 10mm x 50mm is subjected to tension with a load of 200kN and experiences an DESTRUCTIVE TESTING increase in length of 0.10mm. If the length is entirely Tensile Test elastic, calculate the modulus of elasticity of the steel → Maximum amount of pull a material can alloy. withstand → Indicates elastic limit, yield point, percent of area reduction and percentage elongation → Tensile Strength - maximum load divided by the original cross-sectional area → Tensile Strength of metal increases as hardness Impact Test → Measures toughness of metal or ability to withstand sudden shock or impact → TWO TEST: a. Charpy Test b. Izod Test I. 10-mm-square specimen II. Swinging Pendulum of fixed mass raised to standard height SAMPLE PROBLEM Charpy Test A rod with a length of 1 m and a radius of 20 mm is ٥ Specimen mounted in fixture and supported made of high-strength steel. The rod is subjected to a at both ends with V or notch placed on the torque T, which produces a shear stress below the side opposite direction of pendulum’s swing proportional limit. If the cross section at one end is ٥ Pendulum strikes, knife edge strikes sample rotated 45 degrees in relation to the other end, and ٥ Difference in height of pendulum at the shear modulus G of the material is 90 GPa, what beginning and end indicates amount of is the amount of applied torque? energy used to fracture specimen Izod Test ٥ One end of specimen is gripped in clamp with notched side toward the direction of pendulums swing ٥ Amount of energy required to break specimen on scale Torsion Test → Determine the behaviour of a material exhibits when twisted or under torsional forces as a result of applied moments that cause shear stresses about the axis → Indicates torsional shear stress, maximum torque, shear modulus and the angle of twist