Short Notes for Construction Material

Construction Material

summary of Lectures
By Eng I.D Wijesiri

 
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three types of geological classification of stones.   

Igneous rocks

Sedimentary Rock

Metamorphic Rock

 formation of igneous rocks.                                               

Rocks that are formed by cooling of magma (Molten or Pasty rocky materials)  are known as Igneous Rocks

examples for igneous rocks. .                                                    

Granite, Basalt and Dolerite

uses of stones as building materials.                           

Several sizes of stones were used for Building Martials.  Hard stones are formed of Igneous Rocks (metal, Rubble and sand) use for rubble foundation work, concreting works and plastering. Sedimentary rocks are not harder than igneous rocks. (Eg Lime Stone used for lime mortar). Hard Stones (Eg Granite) are used Floor tilling, wall tilling and specials decorative works


uses fine aggregate as building materials.               

Course and fine aggregates are used for Concreting works and Plastering works. Fine aggregate most suitable Mortar preparation


grading of aggregates                                                     

Sieve the sand or metals by series of standard sieves stated by BS codes and preparation of chart for percentage passing of various sizes of sand draw the graph sieve size Vs Percentage passing. By observing   graph identify the grading sizes including test sample. This process is name grading of sand

Or

Sample of sand taken from bulk supply and do sieve Analysis

Or

By Trial – in this method proportionating aggregate by giving highest weight to concrete   

difference between coarse and fine aggregate                    

Fine aggregate named as sand with particle pass through the 4.7625 mm BS sieve is

sizes to be match with coarse aggregate                      

Particles greater than 4.7625mm and less than 20mm is known coarse aggregate. Percentages of each size are decided by sieve analysis

sizes to be match with fine aggregate                                   

A particle sizes less than or equal 4.765 mm known as fine aggregate. Sieve analysis done fine percentage of each sizes in samples

meaning of  R.C.C, and    O.P.C 

Reinforce Cement Concrete

Ordinary Portland Cement                                         

row material used for manufacturing Portland cement        

Calcium Oxide (calcareous Materials Lime Stones, Chalk or Oyster Shell)

Silica and Aluminium Clay, sales, Blast furnace slag

Gypsum

Or Chemical Name

Tricalcium Silicate (C3S)

Dicalcium silicate    (C2S)

Tricalcium Aluminate (C3 A)

Tetra Calcium Aluminoferrite (C3AF)

      I.           manufacturing Portland Cement                           

Dry process

Wet Process

important ingredients (elements) in Cement                             

Gypsum - controlling setting time of cement

Alumina – Controlling Strength and setting time

Silica   -   Quick setting Property

Lime – Controlling strength (More lime- reduce strength)

Vicat apparatus is used for find the initial setting time of cement  

300gms of cement paste (just after mix water) put in vicat apparatus container and drop the needle freely on paste. Measure time to take to reach the needle only 5 to 7 mm above the bottom. That is the initial setting time of cement (Loss of Plasticity).