REVIEW OF LECTURE #2 COMPRESSIONTENSION TORSION THIRD POINT LOADING SPLIT TENSILE WE FINISHED STRENGTH OF MATERIALS REVIEW....

Strain vs Strain Curves Deformation due to Thermal Expansion WE REVIEWED (CON’T) Modulus of Rupture Elastic Modulus Formulas Aggregate Testing – Seven Test (Must See Video) Explained various drying condtions Reviewed Procedures for Lab

TERMS YOU SHOULD KNOW PROPORTIONAL LIMIT – It is the Last Point before the ratio between stress.vs. strain becomes non-linear Yield Point – the stress at which deformation continues without increase in in the load Young Modulus – Modulus of Elasticity found in tension and compression others… brittle behavior, plastic behavior, elastic behavior, ductile behavior, etc. Elastic Limit – Maximum stress at which material can recover its original shape

LECTURE#2 AGGREGATES Overview Definition: Usually refers to mineral particles but can relate to byproducts or waste materials. (i.e. vitrified soils) Natural aggregates are formed from rocks or the decomposition and transport of rock (see fig 2-2) Natural sources include underwater, land ( stripping), Glacier Outwash.

Note: Disadvantage of natural aggregate deposits is: the content of impurities and dust. Rounded shapes and smooth surfaces are found with natural aggregates which is undesirable. However in some locations it may be more economical. Advantage of crushed stones: Size of the particle can be manufactured as needed Also angular shapes and rough surfaces are formed which is better suited for industry AGGREGATES TESTING (cont’d)

Rock Types Igneous Rock - Volcanic Rock which was molten at one time and then cooled i.e. Granites(CG), Basalt(FG) & Diabase Trap Rock is Basalt and Diabase Pumice and Scoria are rock filled with bubbles which are good for lightweight aggregate Trap Rock is an excellent aggregate Sedimentary Rock - Shows a lot of stratification from its natural deposition If it is a sand deposit formed rock it is known as sandstone or quartzite If it is a gravel deposit formed rock it is known as a conglomerate Note: Shale is not a great aggregate because of cleavage AGGREGATES TESTING (cont’d)

Metamorphic Rock - Formed from Sedimentary or Igneous under heat and pressure i.e Shale turns into slate i.e. Limestone turns into marble What qualities do we want in Aggregates? Weight- Prevents erosion of banks or for gabion retaining walls Resistance - For weathering and freeze/thaw To breaking and crushing To resistance to abrasion Ability- to transmit compressive forces as a mass to adhere to a cement agent Permeability- potential as a filtering or drainage system

What is Aggregates Strength Characteristic? See P. 40 Fig 2-12 in Text See Sample Problem!!

Book Notes –Chapt. 2 Earthmoving Basics: SOILS: SP SW GP GW

Book Notes –Chapt. 2 Earthmoving Basics: SOILS: Gravel Clay and Silt Sand

Book Notes –Chapt. 2 Earthmoving Basics: –Load Factor Spoil Banks and Spoil Piles: