CE SummerDr SaMeH1 Properties of Materials & Strength 2 (CE 212) [3] Associate Professor of Environmental Eng. Civil and Environmental Engineering Department Faculty of Engineering Majma’ah University faculty.mu.edu.sa/smohamed/SaMeH Summer Semester Sameh Saadeldin Ahmed

Part I: Physical Properties of Materials CE SummerDr SaMeH2 Chapter (2a) Properties of Materials

Material Properties 1. Physical properties 2. Mechanical properties 3. Chemical properties CE SummerDr SaMeH3

Physical Properties color size texture melting point boiling point solubility luster density magnetism odor viscosity crystalline structure

Physical Properties Electrical properties –conductor or insulator Optical properties – response to light –index of refraction – bending of light –transparent – light passes through –translucent – some light passes through but no distinct image –opaque – no light passes through

Physical Properties Thermal properties – response to heat –Conductivity –Specific heat – how much energy it takes to change temperature –Thermal expansion – example: iron wire demo

Physical Properties 1) Color 2) Specific heat 3) Density 4) Thermal conductivity 5) Melting point 6) Electrical conductivity 7) Coefficient of thermal expansion CE SummerDr SaMeH7

1)Color: light wave length. 2) Specific heat : t he heat required to raise the temperature of one gram of a substance by one degree centigrade. 3) Density: mass per unit volume expressed in such units as kg/cm 3 CE SummerDr SaMeH8 Quick Idea and definitions

4) Thermal conductivity: rate at which heat flows through a given material 5) Melting point : a temperature at which a solid begins to liquify. 6) Electrical conductivity : a measure of how strongly a material opposes the flow of electric current (Ω ⋅ m) CE SummerDr SaMeH9 Quick Idea and definitions

7) Coefficient of thermal expansion: degree of expansion divided by the change in temperature (m/°C) CE SummerDr SaMeH10 Quick Idea and definitions

CE SummerDr SaMeH11 1.Density a) Bulk density b) Apparent density c) True density 2.Specific Weight 3.Porosity 4.Solidity 5.Hydro-properties of Materials 6.Thermal Properties In this Chapter…

What is Density? Density is the Mass per unit Volume WoodWaterIron 1 cm 3 If you take the same volume of different substances, then they will weigh different amounts g 1.00 g 8.00 g Q) Which has the greatest mass and therefore the most dense? IRON

Density = Mass Volume g or k g cm 3 or m 3 gcm -3 or kgm -3  = m V Example: Q) Liquid water has a density of 1000 kgm -3, while ice has density of 920 kgm -3. Calculate the volume occupied by 0.25 kg of each. Density Equation: m V  V1 = m = 0.25 = m 3  1000 V2 = m = 0.25 = m 3  920

Density of a Regular Solid Find the Mass of the solid on a balance. Measure the three lengths and calculate the Volume. (ie V = l x w x h ) Calculate the Density. 4.0 cm 2.0 cm 3.0 cm  = m = 240 =10.0 g/cm 3 V 24 m = 240 g

Densityg/cm 3 Aluminium2.70 Brass8.50 Iron7.87 Wood0.50 Slate2.80 Glass2.50 Lead11.34 Marble2.70 Wax0.89

Density of an Irregular Solid Find the Mass of the solid on a balance. Fill the Measuring Cylinder with Water to a known Volume. Add the Object. Work out the Volume of Water that is displaced. Calculate the Density. 50 cm 3 80 cm 3 m = 360 g  = m = 360 =12.0 g/cm 3 V 30

Density of an Irregular Solid OR use a Eureka Can to find the Volume.   Find the mass of the solid on a balance.  Add water until just overflowing.  Place a Measuring Cylinder under the spout.  Add the Object.  Collect the Water and read off the Volume.  Calculate Density m = 440 g 40.0 cm 3  = m = 440 = 11.0 g/cm3 V 40

Density of a Liquid Find the Mass of an empty Measuring Cylinder. Add a certain Volume of Liquid. Find the Mass of the Measuring Cylinder and Liquid Calculate the Mass of Liquid. How? Calculate Density of Liquid. Mass of Liquid = Mass of Measuring Cylinder and Liquid – Mass of empty Measuring Cylinder 25.0 g 20.0 cm g 45 – 25 = 20 g  = m = 20 =1.00 g/cm3 V 20

Bulk Density Bulk Density (  b) refers to the per unit volume of substance under condition that powdery or granular martial are packed. It is defined by: = = Bulk Volume = A+B+C A = solid volume or true volume B = open pore volume C = closed pore volume A B C B Bulk Density ≠ True Density

Bulk Density Bulk Density is measured refers by volumetric container. The size of the volumetric container depends on the volume of the size of particles. For example, 1 L volumetric container Is used to measure sand, while 10L, 20L and 30L, are used in measurement of stone. =

Bulk Density Test of Sand 1) Weight the mass of the volumetric cylinder m 1 2) Use the spoon to fill the funnel with sand, while the valve is closed. 3) Open the valve of the funnel and let the sand fall into the cylinder slowly until it forms a taper, to the cylinder opening ( the distance between the opening of the funnel and the cylinder opening should not be more that 500 mm). 4) Smoothly, use a ruler to shave in the opposite directions a long the centre line and weight the mass as m 2 5) The bulk density is calculated as: (Accurate to 10 kg/m 3 ) V = volume of volumetric cylinder (L ) =

Apparent Density Apparent Density (  0 ) is the dry mass per unit volume of substance under natural conditions = A C The volume of substance under natural condition refers to the solid volume (A) and the volume of inner pores (C)

Apparent Density Test of Sand 1) Weight a dried sample of 300 g ( m 0 ) and put it in the volumetric flask with half cooled boiled water. 2) Shake the volumetric flask so the specimen is fully stirred and the bubbles expelled, block it with stopper and let the flask stands for 24 hrs. And then add water until the water surface is as high as the bottleneck. 3) Fasten the stopper and clean the water in the outside surface of the flask, then weight the mass as ( m 1 ) 4) Pure the water and the specimen and clean inside and outside surfaces of the flask. 5) Fill the flask with cooled boiled water ( the temperature difference 2 C max.) 6) Fasten the stopper and clean the water in the outside surface of the flask, then weight the mass as ( m 2 ) =

Bulk Density and Practical Density =

William D. Callister Jr, and David G. Rethwi Materials Sciences and Engineering “An Introduction, 9 th Edition. S. L. Kakani, Amit Kakani, (2004); “Material Science Dr. Oussama ElAlowi (CE212- lectures notes ), Civil and Environmental Engineering Department, MU CE SummerDr.SaMeH25 References