Aggregate test

Aggregates test

Crushing strength test on aggregates

Aggregate crushing value gives the crushing strength of aggregate upto which it can be bear the load without fail to conduct crushing strength we need comparison testing machine cylindrical measure plunger and sieves 

Frist sieve the sample aggregate aggregate passing 12.5 mm sieve and retaining 10mm sieve is oven dries at 100-110 centigrade for 3-4 hrs the cylinder is filled with aggregate in three layers 25 stocks of tempering for each letter note down its weight and insert the plunger and placed it on comparison testing machine apply the load at uniform rate of 40 tonnes load in 10 minutes then stop the machine and crashed aggregate is sieve through 2.36 mm sieve and aggregate passing 2.36 mm is weighed 

Aggregate crushing value can be obtained from below formula 

Aggregate crushing value =(w2/ww1)

*100%

                    Abrasion test on aggregates

Hardness property of aggregate is determined by conducting abrasion test Los Angeles abrasion testing machine is used to conduct this test

For these test this sample Tekken should be cleaned and dried the sample is weighed w1 and placed in Los Angles testing machine and the machine is operated machine should be rotated at a speed of 20 to 33 Revolution per minute after 1000 Revelations the sample is taken out and saved through 1.7 mm sieve sample retained on 1.7 mm is washed and dried and note down its weight W2

Aggregate abrasion value=(w1-w2)/w3)×100%

Impact test on aggregates

Impact value of aggregate will give aggregate capability against student loans or Force for this test also aggregate passing through 12.5 mm and written on 10 mm sieve is taken and oven dried

Feel the Slender with aggregate in three layers 25 strokes of camping for each layer weight W one noted the cylinder is placed in impact testing machine which consists a hammer after placing the cylinder hammer is raised to 380 mm and release freely then it will below the aggregates repeated for 15 sets blow blow after that take down the sample and aggregate passing through 2.36 mm sieve is weighed as w2 

Aggregate impact value= (w2/w1)*100%

Soundness test on aggregates

To determine the weathering resistance of aggregate soundness test is conducted if the resistance against weathering is good for aggregates then it will have high durability

For soundness test we need some chemical solution namely sodium sulphate or magnesium sulphate this sample of aggregate passing through 10 mm Sieve and retained on 300 micron sieve is taken .dry and weigh the sample and immerse them in the chemical solutions for about 18 hours .after that take the sample and dried it in oven at 100-110 centigrade repeat this producer 5 times for one sample and wait the aggregate finally and note down the difference in weight loss

The weight loss should be below 12% if sodium sulphate is used below 18% if magnesium sulfate is used

Shape test on aggregates

Shape of aggregate is also important consideration for the construction of pavement aggregate should not contain flaky and orangutan particles in it if they contain this type of particles they will affect the stability of mix  

The percentage by weight of aggregates whose least dimension is less the 3/5th of its main dimension is called as flakiness index

The percentage by weight of aggregate particles whose greatest dimension is 1.8 Times domain dimension is called as elongation  index

In this test shape test gauge are taken and minimum of 200 pieces containing sample is passed through respective case material written on thickness Gauge and material written on length gauge is wait to an accuracy of 0.1% 

      Water absorption test on aggregate

This test helps to determine the water absorption value of aggregates to perform this test minimum 2 kg sample should be used this sample should be cleaned and dried place the sample in wire basket and dip the basket in distilled  water bath to lift and deep the basket for about 25 times in 25 second

Leave the basket for 24 hours and after that allowed it to drain for few minutes aggregate should be taken on dry cloth and exposed them to autumn spare sunlights after drying with the aggregate w1 then place the aggregate in oven at 100to 110 centigrade centigrade for 24 hours after oven drying again wait the aggregate w 2

Water absorption of aggregates=(w1-w2)/w2×100%