Soundness of cement may be determined by two methods, namely Le-Chatelier method and autoclave method. 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.
- 1 What is Le Chatelier test for cement?
- 2 Which equipment is used for finding the soundness of cement?
- 3 What is fitness test of cement?
- 4 What is a bearing certificate?
- 5 How do I get a certificate of structural adequacy?
What is the soundness of cement?
3 Soundness – The soundness of cement refers to the stability of the volume change in the process of setting and hardening. If the volume change is unstable after setting and hardening, the concrete structures will crack, which can affect the quality of buildings or even cause serious accidents, known as poor dimensional stability.
The cement product whose dimensional stability is poor will be disposed as spoiled product, not used in projects. The reasons for poor dimensional stability are: the free calcium oxide ( f -CaO) in the clinker is too much, or the free magnesium oxide in the clinker ( f -MgO) is quite a little, or the gypsum mixed in the clinker is excessive.
f -CaO and f -MgO in the clinker are all sintered, so their ageing speed is very slow. They start ageing slowly after the setting and hardening. CaO + H 2 O = Ca OH 2 MgO + H 2 O = Mg OH 2 In the ageing process, there is volume expansion which causes the cracking of cement.
The excessive amount of gypsum will react with the solid calcium aluminate hydrate to generate crystals of calcium sulfoaluminate hydrate. Thus, the volume will expand 1.5 times, which leads to the cracking of cement paste matrix. The national standards require: boiling method can be used to inspect the poor dimensional stability of the cement caused by the free CaO.
The so-called boiling method includes Pat test and Le Chatelier test. Pat test is to make the cement paste of normal consistency into cement cake, boil it for 3 h, and then observe it by naked eyes. If there is no crack and no bending by ruler inspection, it is called qualified soundness.
Le Chatelier test is to measure the expansion value after the cement paste is boiled and get hardened on Le Chatelier needles. If the expansion value is within the required value, its stability is qualified. If there is contradictory between the results measured by Pat test and Le Chatelier test, Le Chaterlier test should prevail.
The hydration of free magnesium oxide is slower than that of free calcium oxide. Therefore, its harm can be inspected only by autoclave test. The harm of gypsum will be found by immersing in room-temperature water for a long time. Then the poor dimensional stability caused by magnesium dioxide and gypsum is inconvenient to be tested rapidly.
- Thus, they should be controlled strictly in the production of cement.
- The national standards require: the content of free magnesium oxide in cement should not be more than 5.0%, and the content of sulfur trioxide in slag cement should not be more than 4.0% and that in other kinds of cement should not exceed 3.5%.
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What is soundness under physical testing of cement?
🕑 Reading time: 1 minute Soundness of cement can be defined as its ability to retain its volume after it gets hardened. This means that a properly sound cement will undergo minimum volume change after it converts into the hardened state. In the soundness test of cement, we determine the amount of excess lime.
What is Le Chatelier test for cement?
Free RSMSSB JE General Knowledge Free Mock Test 10 Questions 10 Marks 8 Mins For quality control of Portland cement, the test essentially done is 1) Le Chatelier Test : This test is used to measure the soundness of OPC due to lime. Lime & Magnesia are two primary compounds responsible for the soundness of cement.2) Blaine Air Permeability : It is used to measure the fineness of the cement.4) The Vicat Apparatus : It is used to measure setting time and consistency of concrete.5) Tensile (Briquette) Testing Machine: It is used to measure the tensile strength of the concrete Last updated on Sep 22, 2022 The DV Dates for the RSMSSB JE (Agriculture) have been announced.
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Why soundness test is done?
Significance of Soundness of Cement – The testing of the soundness of cement, to ensure that the cement does not show any appreciable subsequent expansion of prime importance. The unsoundness is occurring mainly due to an excess lime that could be combined with acidic oxide at the kiln,
- This is also due to inadequate burning or insufficient fineness of grinding or thorough mixing of raw materials,
- It also may occur due to too high a proportion of magnesium content or calcium sulfate content may cause unsoundness in cement,
- For this reason, the magnesia content allowed in cement is limited to 6 percent, It can be recalled that to prevent flash setting, calcium sulfate is added to the clinker while grinding,
The quantity of gypsum added will vary from 3 to 5 percent depending upon C3A content, If the addition of gypsum is more than could be combined with C3A, excess gypsum will remain in the cement in Free State. This high percentage of gypsum leads to an expansion and consequent disruption of the set cement paste,
What is soundness certificate?
Vets call it a “pre-purchase certificate” – a soundness certificate is like a roadworthy for horses. After spending a lot of money on a new horse, the last thing you need is for it to sit in a stable consuming expensive hay and concentrate because it can’t be ridden.
- A pre-purchase certificate is a legal document, signed by a registered veterinarian, which certifies that a full examination of an identified horse has taken place.
- Issue date: 9 January 2009 – Vets call it a “pre-purchase certificate” – a soundness certificate is like a roadworthy for horses.
- After spending a lot of money on a new horse, the last thing you need is for it to sit in a stable consuming expensive hay and concentrate because it can’t be ridden.
A pre-purchase certificate is a legal document, signed by a registered veterinarian, which certifies that a full examination of an identified horse has taken place on a specified date. Buyers should also pay for the certificate, to ensure the certifying vet is working in your interest, which is to buy a horse suitable for its intended use.
You should, of course, also choose a vet who regularly sees a lot of horses rather than one whose main interest is dogs and cats. Once you’ve contacted the vet and made an appointment for them to visit the horse, it’s a good idea to tag along and watch what’s being done. The British Equine Veterinary association describes five stages for a pre-purchase examination.
First, the horse is examined in the stable to see if it shows any vices like crib-biting or weaving, kicking or refusing to be handled. At this stage the vet will also listen to the heart and lungs, palpate the head, neck, body and tail and feel along the legs.
- The joints will be gently manipulated and flexed to see if they move freely.
- This shouldn’t be done by an amateur as it can damage the ligaments if done roughly, leading to temporary or even permanent lameness.
- The teeth will also be examined to confirm the horse’s age – it’s not uncommon to find it’s several years older, or even younger, than the seller claims.
To substantiate the horse’s identity and history and fill in the certificate properly, the vet will need copies of its passport or registration forms, the number of its DNA test or identity chip and a vaccination certificate. If the owner vaccinated the horse, the vet may need to redo the vaccines so they can be certified.
This is particularly important for equine influenza and tetanus vaccinations, which sellers may claim have been done. The second stage is examining the horse while it’s moving. It’s taken out of the stable to a level, hard surface and first walked and then trotted out. The vet will look at the movement from the front, back and both sides, checking for any irregularity or lameness.
The person who leads the horse should keep it on a long, loose, lead, so that their movement doesn’t cause what is known as “bridle lameness” – an unevenness in the pace caused by the handler hanging to tightly onto the lead-rope or reins. At the third stage the horse is exercised strenuously.
- This is often done on the lunge, but for a riding horse it can also be done under saddle.
- Depending on fitness, the horse should be worked for at least 10 to 20 minutes at a work and trot on the circle.
- If it’s being ridden, saddling, bridling and mounting procedure is also observed – horses with sore backs, withers or necks will often flinch as the riders mount.
The vet notes whether any stiffness is seen when the horse moves around corners in both directions. A jumper should also be worked over jumps. Directly after exercise, the veterinarian will listen for any abnormal breathing and check the heart rate. At the fourth stage the horse is returned to its stable and allowed to rest for 10 minutes, after which the heart and respiration rate should have nearly returned to the resting rate.
- Stiffness or lameness are also re-checked and the horse is once again trotted out gently.
- During the fifth stage, the vet can use a hoof tester and may suggest further tests be done.
- For more expensive horses these usually include X-rays (especially of the lower legs, to eliminate ringbone), endoscopy (to check for stomach ulcers or sinus abnormalities) and blood tests for diseases such as dourine.
If your vet suspects the seller has given a pain-killer to mask lameness, or a tranquilliser, he may suggest a blood test to check for pharmacological substances. If you’re buying a stallion or mare for breeding, it is essential to test for fertility and contagious venereal diseases.
Which equipment is used for finding the soundness of cement?
Permeability apparatus : It is used to measure the fineness of the cement.
Which apparatus is generally used to measure the soundness of cement?
The Laboratory Cement Autoclave is suitable for conducting accelerated soundness tests on Cement or the Autoclave expansion test.
What is fitness test 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.2.
What is flakiness and elongation test?
Table 1 : Dimensions (Length and Thickness) of Gauges – Separation of Flaky material- Each fraction shall be gauged in turn for thickness on a metal gauge of the pattern shown in Fig.3, or in bulk on sieves having elongated slots. The width of the slot used in the gauge or sieve shall be of the dimensions specified in co1.3 of Table 1 for the appropriate size of material. The total amount passing the gauge shall be weighed to an accuracy of at least 0.1 percent of the weight of the test sample. The Flakiness Index is the total weight of the material passing the various thickness gauges or sieves, expressed as a percentage of the total weight of the sample gauged. Separation of Elongated Material- Each fraction shall be gauged individually for length on a metal length gauge of the pattern shown in Fig.4. The gauge length used shall be that specified in co1.4 of Table 1 for the appropriate size of material. The total amount retained by the length gauge shall be weighed to an accuracy of at least 0.1 percent of the weight of the test sample. The elongation index is the total weight of the material retained on the various length gauges, expressed as a percentage of the total weight of the sample gauged.
What is legal soundness?
Definitions of soundness the fact of being in good condition, reliable, or effective.
What is a bearing certificate?
A credit-bearing certificate is a prescribed set of courses leading to a credential that should be focused on a defined set of skills or structured expertise.
How do I get a certificate of structural adequacy?
The Certificate of Structural Adequacy typically contains: –
The logo and contact details of the company that issued the certificate The date of inspection and date of issue of the certificate The full address of the property affected A background to the structural damage experienced The understood cause of the damage The full extent of the repair work carried out, and by whom A statement confirming that the affected part of the property is structurally sound A statement confirming limitation of liability of the company issuing the certificate Notes concerning the transfer of the certificate Signature and/or details of the person issuing the certificate