Soundness of Cement. – Soundness of cement is the ability of a hardened paste to retain its volume after setting. A cement is said to be unsound (i.e., having lack of soundness) if it is subjected to delayed destructive expansion. Unsoundness of cement is due to presence of excessive amount of hard-burned free lime or magnesia. This depends on its original composition, proper burning, and grinding. Presence of lime in the free state, an excess of sulfate or magnesia and a very fine size may be the cause of soundness in cement. The Indian Bureau of Standards has specified the le chatelier apparatus test – the same as adopted by British and American Standards for soundness test of cement.
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Why do we test soundness of cement?
In the soundness test a specimen of hardened cement paste is boiled for a fixed time so that any tendency to expand is speeded up and can be detected. Soundness means the ability to resist volume expansion.
What is J ring apparatus?
Material testing equipment The is used for determining the passing ability, the flow spread and t500 flow time of the self compacting concrete as the concrete flows through the J-Ring. The apparatus consists of a stainless steel crown with 16 bars 18 mm dia. : Material testing equipment
In which test Vicat apparatus is used?
Standard Vicat Apparatus has a reversible stainless steel plunger and needle assembly for 300g total weight. It is used to determine consistency and initial/final set times of cements and mortar pastes.
Which test is used for soundness of bricks?
Answer (Detailed Solution Below) – Option 4 : A – II, B – III, C – IV, D – I Free CT 1: Building Materials (Building Stones) 10 Questions 10 Marks 7 Mins Explanation: Hardness test: In this test, a scratch is made on a brick surface with a hard thing.
If that doesn’t leave any impression on brick then that is good quality brick. Water absorption test: In this test, bricks are weighed in dry condition and let immersed in fresh water for 24 hours. After 24 hours of immersion, those are taken out from the water and wipe out with a cloth. Good quality brick doesn’t absorb more than 20% water of its own weight.
Soundness test: In this test two bricks are held by both hands and stuck with one another. If the bricks give a clear metallic ringing sound and don’t break then those are good quality bricks. Compressive strength test: In this test, a brick specimen is put on a crushing machine and applied pressure till it breaks.
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What is Le Chatelier test?
Fundamentals of the Le Chatelier test for determine the cement soundness – The test procedure consists of subjecting a sample of cement to a controlled heating, then measure its expansion for estimate the possible risk of late expansion due to hydration of free magnesium calcium oxides.
The test procedure indicates filling two Le Chatelier molds with cement paste (from the same mixing batch), and dip them in a water thermostatic bath. The water in the thermostatic bath is heated from 20 ° C to boiling in 30 minutes, along a uniform temperature rise ramp. After the thirty minutes, the cement specimens must be maintained for 3 hours with smooth boiling.
Once boiling time is finished, the moulded samples are taken and measured the distance between tips of the arms of the mold. The distance between the tips is compared against the distance at 20 celsius degrees. European standards for receipt of cements indicate that the opening of Le Chatelier mold should not be greater than 10 mm.
What is Le Chatelier’s principle?
Le Chatelier’s principle can be stated as follows: A change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change.
What size is J ring?
3. Size Conversion Chart
| Inside Diameter | ||
|---|---|---|
| Inches | MM | UK |
| 0.58 | 14.88 | H |
| 0.59 | 15.10 | I |
| 0.60 | 15.49 | J |
How does the ball and ring apparatus work?
Product Details Brass ball passes freely through ring at room temperature but when the ball is heated in a flame, it no longer passes through the ring. Plastic or wooden handle provides excellent thermal insulation andkeeps hands cool.
What MM is J ring?
UK Ring Size Chart
| Ring Size | Circumference (mm) |
|---|---|
| J | 48.7 |
| K | 50.0 |
| L | 51.2 |
| M | 52.5 |
Which test is used for fineness of cement?
Fineness of cement is tested in two ways : (a) By sieving. (b) By determination of specific surface (total surface area of all the particles in one gram of cement) by air-permeability apparatus. Expressed as cm2/gm or m2/kg.
Which apparatus is used in cement setting test?
Setting Time of cement – Vicat’s apparatus is used to find the setting times of cement i.e., initial setting time and final setting time. Initial Setting Time: For this test, a needle of 1 mm square size is used. The needle is allowed to penetrate into the paste (a mixture of water and cement as per the consistency test). Final Setting Time: After the paste has attained hardness, the needle does not penetrate the paste more than 0.5 mm. The time at which the needle does not penetrate more than 0.5 mm is taken as the final setting time.
Which apparatus is used for fineness of cement?
Fineness of cement is tested in two ways : (a) By sieving. (b) By determination of specific surface (total surface area of all the particles in one gram of cement) by air-permeability apparatus. Expressed as cm2/gm or m2/kg. Generally Blaine Air permeability apparatus is used.
