Testing of stone

1). durability test

I. smith test

Place the fresh chips of stone in normal water in a boucle shake it for well mixing. after ½ hour, if the color of water change, it means acid is present in chip & stone is not 

durable.

II. Acid test

Place the fresh chips in HCl {%} or H2So4 {5%} solution. after ½ hour

if sharp edge of chip gets melted, it means stone is not durable

III. Frets & crystalline test

IV.place the fresh stone in boil water for 24 hour then place it in cool place (temp 

– 12oC) for 24 hour. if the nature of stone is some in both condition it means 

member is durable.

2). strength test

Crushing test

1} 3 specimen of 40 x 40 x 40 each

2} Place in water for 75h

3} 5 mm pop layer on surface

4} 13.72 N/mm2/min

Compressive strength = Load/Cross sectional area

Note: - the min crushing strength in common building stone is in range of 100-110 N/mm2

3). Impact test

→ place the stone in mould & fall the hammer from 305mm height. it the member do not crack then increase the height of fall by 1 cm & again fall the hammer.

➔ The blow at which the specimen break down is note & if it is nth then impact 

index, stronger is the member.

4). Water absorption test

Stone sample --. 50g/100g

[Place it in oven @ 104oC for ½ hr]

Remove the stone from oven 

w1 = dry wt of stone

[Place in water for 24 hour] Temp = 20-30°C

Remove stone from water

W2 = wet wt after 24h

Change in wt = w2-w1

%water absorption = w2-w1/w1

Note : -

for good building stones, max percentage of water absorption is not more than 5%

Attrition test

6cm = 60mm dia specimen → 5 kg

Attrition deval’s testing Machine

30 r.p.m per 5h

1.5 mm sieve analysis

% of wear = (lossin wt)/(Initial wt.)×100

Note: - for the railway ballast, max percentage of wear is 3 %