CONSMAT MODULE 2

Mineral Aggregates

In the form of sand, gravel, crushed stone, crushed slag, pumice and manufactured products.

Natural Aggregates. Manufactured Aggregates

What are the Classification of Mineral Aggregates?

Natural Aggregates

These are taken from natural deposits without change in their nature during production with the exception of crushing, sizing, grading or washing.

Gravel, Crushed Stone, Sand, Pumice, Iron Ore

Example of Natural Aggregates

Manufactured Aggregates

It include blast furnace slug shale and light weight aggregates.

Coarse Aggregates. Fine Aggregates

What are the Two Types of Manufactured Aggregates?

Coarse Aggregates

defined as aggregates predominantly retained on #4 (4.75mm) sieve or that portion of an aggregate retained on the #4 sieve.

Fine Aggregates

defined as aggregates passing a 3/8 inch (9.5mm) sieve and almost entirely passing a # 4 sieve and predominantly retained on the #200 (75μm) or that portion of an aggregate passing the #4 sieve and retained on the #200 sieve.

Igneous Rocks. Sedimentary Rocks. Metamorphic Rocks

What are the classification of Rocks?

Igneous Rocks

They were at one time intensely heated and in a liquid condition known as magma, granite, dionite, gabbio, basalt, and trap rock

Granite

coarse grained and light in color

Basalt

fine grained and dark

Sand and Gravel

They are igneous origin, if the material has not weathered excessively, make good aggregate

Volcanic Scions and Pumice

They are used in some areas for lightweight aggregates

Sedimentary Rocks

They are secondary in their origin; the materials comprising them are the result of weathering of some previously existing rocks.

Common Sedimentary Rocks

They are conglomerates and contain coarse pebbles, sandstone, shale, limestone and dolomite

Sedimentary Rocks

They range from poor to excellent as a source of aggregate. Hard and dense sandstone and limestones are good; shales are usually laminated and of poor quality; conglomerates are poor; dolomite of hard and dense is good.

Metamorphic Rocks

These are rocks that have been metamorphosed, or changed, as a result of tremendous pressure, heat and chemical activity.

Gneiss, Slate, Quartzite, Marble, Schist

Example of Metamorphic Rocks?

Solid Bed Rocks. Deposits of sand and gravel

What are the sources of aggregates?

Excavation and Quarrying, Transportation, Washing, Crushing, Sizing

What are the Processing of Aggregates?

Excavation

removal of overburden (soil), blasting

Organic Materials, Clay and Silt

What are the Deleterious Materials?

Transportation

plant to trucks, rail or conveyors

Washing

to remove deleterious materials

Deleterious Materials

materials that may prove harmful to the final product for which the aggregate is to be used. Includes clay, mud, leaves, etc

Crushing

to reduce the size of the stones or gravel to a desired sizes (gradation)

Jaw Crusher

consist of a fixed jaw and reciprocating jaw

Sizing

Vibratory sieves used for coarse materials

Sizing

Hydraulic classification devices for fine materials

Aggregates Properties

They are defined by the characteristics of both the individual particles, and the characteristics of the combined materials.

Particle Shape and Surface Texture, Particle SIze, Soundness and Durability, Absorption, Specific Gravity, Unit Weight and Voids, Cleanliness, Volumetric Stability

What are the Physical Properties of Aggregate

Solubility, Surface Charge, Asphalt Affinity, Reactivity to Chemicals, Coatings, Volume Stability

What are the Chemical Properties of Aggregate

Compressive Strength, Toughness, Abrasion Resistance, Polishability

What are the Mechanical Properties of Aggregate