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Hra1 Material for Civil Engineering aggregates. hra2.

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Presentation on theme: "Hra1 Material for Civil Engineering aggregates. hra2."— Presentation transcript:

1 hra1 Material for Civil Engineering aggregates

2 hra2

3 3 Definition Materials (for construction) Inert material which, when bound together into a conglomerated mass by a matrix, form: -concrete, - mastic mortar, -plaster. An aggregation of sand, gravel, crushed stone, slag or other material composition used in combination with a binding medium to form: -bituminous and Portland cement, -concrete, -macadam, -mastic, -mortar cement, -plaster, or alone as: -railroad ballast, -filter beds, and -various manufacturing processes such as fluxing

4 hra4 Classification Natural Aggregate Manufactured Aggregate

5 hra5 Natural Aggregates  Taken from natural deposits without change in their nature during production, with the exception of crushing, sizing, grading or washing  Includes:  pumice,  shells,  iron ore,  lime rock

6 hra6 Manufactured Aggregates  Aggregates produced as a direct product, rather than as a by-product of a manufacturing process  Includes:  Blast furnace slag  Clay  Shale;  Light weight aggregates

7 hra7 Synthetic – Artificial Aggregates  By-product of an industrial process  Product of process developed to manufactured aggregate with special properties  Reclaimed or waste construction materials

8 hra8 Classification based on Size  FINE Aggregate passing 9.5mm (3/8”) sieve, passing sieve no 4 (4.75mm) and predominantly retained on 75u (no 200) sieve Aggregate passing no 4 and retained on the no 200 (75um) sieve  COARSE Aggregate predominantly retained on the no 4 sieve (for Portland Cement Concrete) The no 8 or no 10 sieve (for bituminous concrete)

9 hra9 Composition & Structures  Natural Aggregates  Consist of naturally occurring material of mineral composition  Derived from rocks with single mineral or several different mineral

10 hra10 NATURAL AGGREGATES METAMORPHIC ROCK IGNEOUS ROCK SEDIMENTARY ROCK

11 hra11 Composition & Structures  IGNEOUS ROCK  COOL MELTING FORMED (ABOVE OR BELOW THE EARTH’S SURFACE)  CONSISTS OF CRYSTAL OR MINERALS IN A CRYSTALLINE (OR GLOSSY) MATRIX  SIZE IS A FUNCTION OF COOLING RATE

12 hra12 Composition & Structures  SEDIMENTARY ROCK  FORMED BY THE CONSOLIDATION OF DEPOSITS, - WEATHERING PRODUCTS AND EROSION OF ROCKS (EARTH SURFACE)  LESS MECHANICAL COMPACTIONS

13 hra13 Composition & Structures  METAMORPHIC ROCK  FORMED BY THE APPLICATION OF INTENSE HEAT AND PRESSURE TO SEDIMENTARY ROCKS  LESS POROUS, STRONG MATRIX (RECRYSTALLIZATION)  STRONGED AND LESS ANISOTROPIC COMPACTED TO SEDIMENTARY ROCKS

14 hra14 ROCKSTYPESpecific Gravity POROSITY (% - vol) IGNEOUSBasalt Granite 2.6 – 3.0 50 – 200 100 – 250 SEDIMENTARYShale Limestone Sandstone 2.0 – 2.7 2.3 – 2.8 2.2 – 2.7 10 – 100 35 – 250 20 – 175 METAMORPHICState Marble Quartzite 2.6 – 2.9 2.6 – 2.8 2.6 – 2.7 100 – 200 100 – 250 100 - 300

15 hra15 Principles and Procedures  The use and process:  QUALITY : high (estimate)  COST : low (estimate)  The procedures:  Excavation  Transportation  Washing  Crushing  Sizing

16 hra16 procedures Processing plant Site Transportation (truck, rail, conveyor belt) Washing : before and/or after Excavator: digging Removal of organic material (silt; clay; leaves; mud) Method: blasting; dragging; pumping

17 hra17 Sizing and screening 1.Sizing: by crusher 2.Proper and desirable size 3.Crusher type: size of designed aggregate Sieve : vibratory screen Set of sieves with designated diameter

18 hra18 d sieve d D

19 hra19 Sieve analysis h D X gram (X- z) gram Retained = coarser X’ gram coarser X” gram finer X”‘ gram finer

20 hra20 Grain distribution 1010.10.010.0.01 0 20 60 80 100 % by weight finer Diameter, log, mm 40

21 hra21 End of session


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