CMT

• Laboratory apparatus & equipment used in testing of materials

  • Sieve Set
  • Balance Beam
  • Graduated Beaker
  • Slump Cone
  • Various Molds
  • Hydrometer
  • Universal Testing Machine
  • Concrete Mixer
  • Pressure Gauge
  • Vicat Apparatus
  • Electric Oven
• Balance Beam or Weighing Scale

  A device to measure weight or mass, also known as mass scales, weight scales, mass balances, weight balances, or simply scales, balances, or balance scales

  
• Balance Beam

  • Traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum
  • One plate holds an object of unknown mass (or weight), while known masses are added to the other plate until static equilibrium is achieved and the plates level off
  • Perfect scale rests at neutral
  • Spring scale uses a spring of known stiffness to determine mass (or weight)

  
• Graduated Beaker


  A cylindrical container with a flat bottom, usually with a small spout (or "beak") to aid pouring, available in a wide range of sizes from one milliliter up to several liters
• Slump Cone


  A metal mold in the form of truncated cone used to fabricate the specimen for a slump test, which measures the workability of fresh concrete
• Types of molds used in material testing lab for preparation of concrete specimen

  • Cube Molds (150mm x 150mm x 150mm, 100mm x 100mm x 1000mm, 70.6mm x 70.6mm x 70.6mm)
  • Cylinder Molds (6 x 12 in. (15.2 x 30.5 cm), 4 x 8 in (10 x 20 cm))
  • Beam Molds (100x100x400 mm, 100x100x500 mm, 150x150x600 mm)
• Universal Testing Machine (UTM)

  Used to test the mechanical properties (tension, compression etc.) of a given test specimen by exerting tensile, compressive or transverse stresses
• Concrete Mixer

  A device that homogeneously combines cement, aggregate such as sand or gravel, and water to form concrete, often with a revolving drum
• Electric Oven


  Designed for the drying of asphalt, soil, rock, concrete, aggregate or similar materials
• Quality is characteristic of a product that provides a level of performances in terms of service and life
• 3 keys in quality control


  • Owner
  • Implementer
  • Quality
• Quality Control


  To regulate and accompanied by economical work, safety and beauty
• Quality control procedures


  • Selection of Materials
  • Handling and Storage of Materials
  • Sampling and Testing of Materials
  • Proper Construction Methods
  • Inspection and Project Monitoring
• Types of materials for selection


  • Raw materials (soil, sand, bank/river gravel)
  • Processed materials (washed/manufactured sand, crushed rock and gravel)
  • Manufactured materials (bituminous materials, cement, paint, structural reinforcing steel bar)
  • Combination of materials (bituminous and Portland cement concrete)
• Handling and Storage of Materials


  Materials should be placed in a safe place protected from contamination or the action of water to avoid damage
• Sampling and Testing of Materials

  All materials for testing requires proper sampling as indicated in AASHTO and ASTM, and proper testing, construction method and workmanship
• Minimum Testing Requirement


  Quality stated in the program of works is the basis, specifying the kind and number of tests for each item and sizes, but this is only the minimum and additional testing can be done if needed
• Proper Construction Methods


  • Technical personnel assigned should be knowledgeable and responsible
  • Project Supervision hierarchy (Project Engineer, Project Inspector, Materials Engineer, Safety Engineer, Construction Foreman, Skilled and Unskilled Laborers)
  • Construction methods shall be done for each work indicated in the design
  • Materials shall pass the required specifications
  • Continuous quality control should be done
  • Proper equipment for each work item shall be used
  • Materials quantity shall be well provided
• Inspection and Project Monitoring


  Project inspected is vital to ensure the materials and workmanship is being done by the hired contractor
• Quality Assurance


  The certainty that the materials are regulated in accordance with specifications
• Purpose of Quality Control


  • To ensure the highest quality of work and extend the service life of any structure by constructing according to the prescribed plans and specifications
  • To check and regulate the use of construction materials and to economize on the cost of construction
• Material properties


  • PHYSICAL
  • CHEMICAL
  • MECHANICAL
  • ELECTRICAL
  • THERMAL
  • MAGNETIC
• Density


  Mass per unit volume of material
• Density values

  • Water: 1000 kg/m3
  • Cement: 1440 kg/m3
  • Steel: 7850 kg/m3
  • Asphalt: 2400 kg/m3
• Specific weight


  Unit weight, weight per unit volume of material. Specific weight is equal to the product of density of material and standard gravity due to acceleration.
• Water permeability


  The ability of a material to permit water through it. Dense materials like glass, metals etc. are called impervious materials which cannot allow water through it.
• Weathering resistance


  The property of a material to withstand against all atmospheric actions without losing its strength and shape. Weathering effects the durability of material. For example corrosion occurs in iron due to weathering. To resist this paint layer is provided.
• Pavement may fail due to excessive roughness at the surface, even though the stress levels are well within the capabilities of the material. A building may have to be closed due to excessive vibrations by wind or other live loads, although it could be structurally sound.
• Types of loads


  • STATICS
  • DYNAMIC
  • PERIODIC - harmonic or sinusoidal load, repeats itself with time
  • TRANSIENT - an impulse load that is applied over a short time interval
  • RANDOM - the load pattern never repeats
• Stress


  Force per unit area
• Strain

  Deformation per unit length
• A cube made of alloy with dimensions 50mm x 50mm x 50mm is placed into a pressure chamber and subjected to a pressure of 90 MPa. If the modulus of elasticity of the alloy is 100 GPa and Poisson's ratio is 0.28, the length of each side of the cube, assuming that the material remains within the elastic region, will be 49.9802 mm.
• Linear material


  • Stress-strain relationship follows a straight line
• Elastic material


  • Returns to its original shape when load is removed and reacts instantaneously to changes in load
• For materials that do not display any linear behavior, such as concrete and soils, determining a Young's modulus or elastic modulus can be problematical. There are several options for arbitrarily defining the modulus for these materials: initial tangent modulus, tangent modulus, secant modulus, and chord modulus.
• Methods for approximating modulus

  • Initial tangent modulus - slope of the tangent of the stress-strain curve at the origin

  Tangent modulus - slope of the tangent at a point on the stress-strain curve

  Secant modulus - slope of a chord drawn between the origin and an arbitrary point on the stress-strain curve

  Chord modulus - slope of a chord drawn between two points on the stress-strain curve
• Plastic material behavior


  • When the load is removed, some of the deformation will be recovered and some will remain

  Elastic-perfectly plastic - linear elastic response upon loading, followed by a completely plastic response

  Elastoplastic with strain hardening - elastic response followed by a combined elastic and plastic response
• An elastoplastic material with strain hardening has a stress-strain relationship where the modulus of elasticity is 175 GPa, yield strength is 480 MPa, and the slope of the strain-hardening portion of the stress-strain diagram is 20.7 GPa. The strain that corresponds to a stress of 550 MPa is 0.0061 m/m, and the permanent strain when the 550 MPa stress is removed is 0.0030 m/m.
• Viscoelastic materials


  Such as plastics and asphalt, are greatly affected by temperature, even if the temperature is changed by only a few degrees. Metals or concrete are less affected by temperatures, especially when they are near ambient temperature.
• Modulus of resilience


  The area under the elastic portion of the stress-strain curve