Free CT 1: Current Affairs (Government Policies and Schemes) 10 Questions 10 Marks 10 Mins Standard consistency test: This test determines the percentage of water required to make workable cement paste. Vicat’s apparatus is used to perform this test. Temperature during test = 27 ± 2°C Relative humidity = 90% As per Vicat’s test ‘the percentage of water added to the cement at which the needle can not penetrate 5-7 mm from bottom of the mould is called consistency.

Sr no	Tests on cement	Apparatus or method
1	Fineness test	Sieve method or Air permeability test
2	Standard consistency test	Vicat’s apparatus
3	Initial setting time test	Vicat’s apparatus (Vicat’s needle)
4	Final setting time test	Vicat’s apparatus (Vicat’s needle)
5	Compressive strength test	Universal Testing Machine (UTM)
6	Tensile strength test	Standard briquettes test Michaeli’s compound lever apparatus
7	Soundness test	Le-chatelier’s apparatus

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Which apparatus is used to determine the consistency of?

Modified Vicat Apparatus 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.

What are the apparatus that is being used in testing the quality of the cement?

Vicat Apparatus is used to determine consistency and time of the set of cement paste and other similar materials, Vicat Apparatus is also available in a modified model for determination of false set.

What is Le Chatelier apparatus used for?

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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Which of the following is used to test the normal consistency of cement?

Concrete Technology Questions and Answers – Standard Consistency Test This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Standard Consistency Test”.1. Why do we need Standard Consistency Test? a) To determine the quality of cement b) To determine the quality of water c) To determine the quality of mixed concrete d) To determine the strength of concrete block View Answer Answer: b Explanation: This test is performed to determine the quantity of water required to produce a cement paste of standard or normal consistency.2.

What is standard consistency? a) Consistency which permits the Vicat’s plunger b) Ability of cement to maintain a constant volume c) Durability in sea water d) Free lime content View Answer Answer: a Explanation: Standard consistency of cement paste may be defined as the consistency which permits the Vicat’s plunger (10 mm, 40 to 50 mm in length) to penetrate to a point 5 mm to 7 mm from the bottom ( or 35 mm to 33 mm from top) of Vicat mould.3.

When the cement paste is tested within the gauging time. Here what is the value of gauging time? a) 3 to 5 minutes b) 3 to 5 hours c) 24 minutes d) 24 hours View Answer Answer: a Explanation: When the cement paste is tested within the gauging time (3 to 5 minutes) after the cement is thoroughly mixed with water.4.

How many moulds required for the compression strength test of cement? a) 1 b) 2 c) 3 d) 4 View Answer Answer: c Explanation: In this test, three moulds of (face area 50 cm 2 ) are prepared and cured under standard temperature conditions and each cube tested by placing it between movable jaws of the compressive strength testing machine.5.

Which of the following option is correct? a) Standard consistency (%) = (wt of water added/ wt of cement) *100 b) Standard consistency (%) = (wt of water added- wt of cement) *100 c) Standard consistency = (wt of water added/ wt of cement) *100 d) Standard consistency (%) = (wt cement/ wt of water) *100 View Answer Answer: a Explanation: To determine the standard consistency, we need to divide the weight of water to cement and then multiply it with 100 to get the percentage of standard consistency.

• Check this: | 6.
• Standard consistency of cement is tested by _ a) Vicat apparatus b) Le Chatalier apparatus c) Soundness meter d) Duff Abrams apparatus View Answer Answer: a Explanation: The standard consistency of a cement paste is defined as that consistency which will allow the vicat’s plunger to penetrate to a point 5 to 7mm from the bottom of the vicat mould.7.

Calculate standard consistency(%) when 100 ml of water is added in 1000 g of cement. a) 10 b) 1000 c) 100 d) 1 View Answer Answer: a Explanation: Standard consistency (%) = (wt of water added/ wt of cement) *100 = 100/1000*100 = 10.8. For making cement paste, what is the amount of water we need? a) 25% water by weight of dry cement b) 30% water by weight of dry cement c) 78% water by weight of dry cement d) 80% water by weight of dry cement View Answer Answer: a Explanation: 25% water by weight of dry cement thoroughly to get a cement paste.

Total time taken to obtain thoroughly mixed water cement paste.9. What is the normal consistency for OPC? a) 26 to 33% b) 20 to 35% c) 26 to 50% d) 33 to 55% View Answer Answer: a Explanation: For a cement paste the standard consistency is measured by flow table test which ranges from 26 to 33%.10. The relative humidity of laboratory should be _ for standard consistency.

a) 65 ± 5% b) 27 ± 2% c) 50 ± 5% d) 45 ± 10 View Answer Answer: a Explanation: Unless otherwise specified this test shall be conducted at a temperature 27 + 20 C and the relative humidity of laboratory should be 65 + 5%. Sanfoundry Global Education & Learning Series – Concrete Technology.

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What is Vicats apparatus?

: a device for determining the normal consistency and time of setting of portland cements that consists of a rod weighing 300 grams, having a needle in each end, and supported in a frame with a graduated scale to measure the distance to which the needle penetrates the cement

What is the best measure of consistency?

A typical device which is used for the determination of consistency is a penetrometer.

Which apparatus is used to determine the consistency of cement Mcq?

Cement MCQ – Objective Question Answer for Cement Quiz – Download Now! Gypsum is added during grinding operation of cement production to facilitate

1. increasing compressive strength
2. delay in setting action
3. increase the soundness
4. increase the fineness

Option 2 : delay in setting action Explanation: Gypsum:

• The purpose of adding gypsum to powdered clinker during the grinding process of cement is to retard the rate of setting
• The chemical formula of gypsum is CaSO 4,2H 2 O,
  • It is added to powdered clinker during the grinding process of cement is to retard the rate of setting.
  • Cement is manufactured using calcium, silicon, aluminium, iron, and ingredients like limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.

Additional Information

Accelerators are used to accelerate the rate of setting,

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Which of the following type of cements is suitable for use in massive concrete structures like large dam?

1. OPC
2. PPC
3. Low heat cement
4. Rapid hardening cement

Option 3 : Low heat cement Explanation: Low Heat Portland Cement:

• It is particularly suited for making concrete for dams and many other types of water retaining structures, bridge abutments, massive retaining walls, piers and slabs etc.
• In mass concreting, there is often considerable rise in temperature because of the heat produced as the cement sets and hardens.
• The shrinkage which occurs on subsequent cooling sets up tensile stresses in the concrete, may result in cracking. The use of low heat cement is advantageous since it evolves less heat than OPC. This cement is not available in the market on regular basis and has to be obtained on specific orders.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Blast furnace slag cement is used for

1. dams
2. bridge abutments
3. retaining walls
4. All of the above

Option 4 : All of the above

• Explanation:
• Blast furnace slag cement is the mixture of ordinary Portland cement and finely granulated blast furnace slag obtained as a by-product in the manufacture of steel with a percent under 70% of that of cement.
• Uses of Blast-Furnace Slag Cement

1. Used in ready-mix concrete plants.
2. Used for structures meant for water retaining such as retaining walls, rivers, ports, and tunnels.
3. Used in mass concreting works such as dams, foundations, and bridge abutments which require low heat of hydration.
4. Used in places susceptible to chloride and sulfate attacks such as sub-structure, bored piles, pre-cast piles, and marine structures.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Heat of Hydration in a cement at early age is maximum for Concept: The composition of portland cement is rather complicated but basically, it consists of the following four major compounds:

1. Tricalcium silicate(C 3 S): 3CaO.SiO 2 (alite)
2. Dicalcium silicate(C 2 S): 2CaO.SiO 2 (belite)
3. Tricalcium aluminate(C 3 A): 3CaO.Al 2 O 3 (aluminate)
4. Tetracalcium alumino ferrite(C 4 AF): 4CaO.Al 2 O 3,FeO 3 (ferrite)

The brown crystals are alite ( C 3 S), the blue crystals are belite (C 2 S), and the bright interstitial material is mainly ferrite (C 4 AF), with small dark inclusions of aluminate (C 3 A).

• The two silicates, namely C 3 S and C 2 S, which together constitute about 70 to 80 percent of the cement, control most of the strength-giving properties.
• Tricalcium silicate (C 3 S) having a faster rate of reaction accompanied by greater heat evolution develops early strength.
• Dicalcium silicate (C 2 S) hydrates and hardens slowly and provides much of the ultimate strength.
• The compound Tricalcium aluminate(C 3 A) is characteristically fast-reacting with water and may lead to an immediate stiffing of paste, and this process is termed a flash set.
• Tricalcium aluminate (C3A) is mostly related to the heat of hydration. It releases a large amount of heat during the first few days of hardening which generally results in early-age cracking.
• Cement with high content of C3A is not suitable for mass concreting and is better to be mixed with fly ash.​​

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students As per IS specifications, the heat of hydration of low-heat portland cement for 28 days is:

1. Not more than 100 calories / gm
2. Not more than 50 calories / gm
3. Not more than 120 calories / gm
4. Not more than 150 calories / gm
5. Not more than 75 calories / gm

Option 5 : Not more than 75 calories / gm Explanation: Low Heat Cement:

• This cement is manufactured by reducing the proportion of C 3 A and C 3 S and increasing the proportion of C 2 S.
• This cement shows a low rate of development of strength (Due to increasing C 2 S).
• This cement is used in mass concreting. Example – Hydraulic structures.
• The low heat cement consists of a lower percentage of C 3 A among all bogue compounds.
• This cement contains a low percentage (5%) of tricalcium aluminate (C 3 A) and a higher percentage (46 %) of dicalcium silicate (C 2 S).

As per IS 12600 clauses 6.7

• When tested according to the method described in IS: 4031-1988 Part 9,
• the heat of hydration of low-heat Portland cement shall be as follows:

a) 7 days – not more than 65 calories per gram or 272 kJ/Kg b) 28 days – not more than 75 calories per gram or 314 kJ/Kg India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students If P is the percentage of water required for normal consistency, water to be added for determination of initial setting time is _.

Type of test	Water to be added (Consistency)
Setting time (both initial and final)	0.85P
Compressive strength test	(P/4 + 3) %
Soundness test	0.78 P

Important Point: Standard consistency is the consistency of the cement paste that permits the Vicat’s plunger of diameter 10 mm and height 50 mm to penetrate in to the mould up to depth of 33 to 35 mm from the top. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students The development of strength of cement and its fineness are:

1. Directly proportional
2. Inversely proportional
3. Not related
4. Randomly related

Option 1 : Directly proportional Explanation: If the fineness of the cement is greater, surface area of the particles of the cement is also greater, And greater surface area leads to an increase in rapid hydration reaction (i.e. exothermic reaction between cement particles and water).

1. 40 – 50%
2. 17 – 25%
3. 3 – 8%
4. 60 – 67%

Concept: The following table shows the composition of cement and its properties.

Ingredients	Within limit	If in excess
Lime (62 – 65%)	Controls strength and soundness	Makes the cement unsound and it expands and disintegrates
Silica (17 – 25 %)	Adds strength to cement, as it forms C 2 S and C 3 S	Causes slow setting of cement
Alumina (3 – 8 %)	Provides quick setting of cement and lowers the clinkering temp	Lowers the strength
Iron oxide (3 – 4 %)	Provides color, hardness, strength and helps infusion of raw material
Magnesia (1 – 3 %)	Provides hardness and color Decreases shrinkage	Makes the cement unsound
Alkalies (0.2 – 1 %)	Should be in limit	Alkali aggregate reaction Efflorescence and staining

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students

1. Identify the correct statements.
2. i. Expanding cement is used for filling the cracks
3. ii. White cement is mostly used for decorative works
4. iii. Portland pozzolana cement produces less heat of hydration
5. iv. High strength Portland cement is produced from the special materials

1. i, ii and iii only
2. i, ii and iv only
3. ii, iii and iv only
4. i, ii, iii and iv

Option 4 : i, ii, iii and iv Expanding Cement: It is obtained from mixing sulpho-aluminate. It has a property to expand, thus used in the elimination of shrinkage cracks. It is used in the treatment of expansion joints and for grouting. White Portland cement: The white colour of this cement is due to less proportion of iron oxide, which is replaced by Sodium Alumino Ferrite.

Colouring agents can be added to white cement to produce coloured cement. Portland Pozzolana Cement: It is formed by inter grinding of OPC clinker to 10% to 25% of pozzolanic material, It produces less heat of hydration and offers greater resistance to the attack of aggressive water than OPC. It is useful in marine and hydraulic constructions.

High strength Portland cement: This cement is produced by a special technique called Macro Defect Free (MDF) innovation. In this process 4-7% of one of several water-soluble polymers (such as hydroxypropyl methylcellulose, polyacrylamide of hydrolyzed polyvinyl acetate is added for generating high strength.

1. 30 minutes
2. 10 hours
3. 1 hour
4. 6 hours

Characteristics of an Ordinary Portland cement (OPC): 1. It is available in 3 grades – OPC 33, OPC-43 and OPC-53 and the number 33, 43, 53 corresponds to 28 days characteristic compressive strength of cement as obtained from standard test on cement.2.

Initial setting time shall not be less than 30 minutes and final setting time should not be more than 10 hours.3. Soundness lies from 5 to 10 mm when calculated from Le-Chatelier’s method.4. Residue by weight shall not be more than 10 % when sieved on 90 micron sieve and sieved for 15 minutes continuously.5.

It tensile strength 10-15 % of the compressive strength.6. Its tensile strength should not be less than 2 MPa and 2.5 MPa after 3 days and 7 days respectively.7. Its compressive strength for 33 grade at 3 days, 7 days, and 28 days is 16 MPa (160 kg/cm 2 ), 22 MPa (220 kg/cm 2 ) and 33 MPa (330 kg/cm 2 ) respectively.8.

1. fat lime
2. Hydraulic lime
3. hydrated lime
4. quick lime

Option 2 : Hydraulic lime Types of lime: 1. Fat lime: It slacks rapidly and its volume is increased by 2 to 2.5 times of its original volume hence, it is referred as fat lime. It is also known as pure lime, rich lime, high calcium lime. It has more than 95% purity.

• Properties- Slow setting, High plasticity, Soluble in water, Vigorous slaking, Perfectly white colour
• Application- White wash & Plastering
• Source- Sea shells

2. Hydraulic lime: It is also known as water lime as it is capable of setting in water and damp condition. It has 70% to 90% purity.

1. Properties – Insoluble in water, Low plasticity, Less slaking, Off white colour, High hydraulicity
2. Application- Brick masonry or Stone masonry
3. Source- burning of Kankar

3. Poor lime: It is also known as Impure or lean lime. It has less than 70% purity. Properties- Muddy Colour Application- Used in brick work around foundation India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Vicat apparatus is used for-

1. Fineness test
2. Consistency test
3. Soundness test
4. None of the above

Option 2 : Consistency test Explanation: Standard consistency test:

• This test determines the percentage of water required to make workable cement paste.
• Vicat’s apparatus is used to perform this test.
• Temperature during test = 27 ± 2°C
• Relative humidity = 90%
• As per Vicat’s test ‘the percentage of water added to the cement at which the needle can not penetrate 5-7 mm from bottom of the mould is called consistency.
• For OPC consistency is around 30%
• In order to make a cement paste of normal consistency, the percentage of water varies from 25 to 35%.

Important Points

Sr no	Tests on cement	Apparatus or method
1	Fineness test	Sieve method or Air permeability test
2	Standard consistency test	Vicat’s apparatus
3	Initial setting time test	Vicat’s apparatus (Vicat’s needle)
4	Final setting time test	Vicat’s apparatus (Vicat’s needle)
5	Compressive strength test	Universal Testing Machine (UTM)
6	Tensile strength test	Standard briquettes test Michaeli’s compound lever apparatus
7	Soundness test	Le-chatelier’s apparatus

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Colored cement (white cement) consists of_ percentage of pigment.

1. 2 to 4
2. 8 to 12
3. 4 to 10
4. 5 to 10

• Colored cement:
• Colored pigment is manufactured by mixing of color pigments (5-10 %) with OPC.
• The pigment is mixed in a finest powdered state.

The main modern white hiding pigment is Titanium dioxide. Zinc oxide is a weaker white pigment with some important usages. Some pigments are toxic, such as those used in lead paint. Paint manufacturers replaced lead white with a less toxic substitute, which can even be used to colour food titanium white (titanium dioxide). Important Points Portland slag cement:

• This cement is prepared by mixing granulated blast furnace slag, hard burnt gypsum, and cement clinkers in suitable proportions.
• This cement offer:
  • The heat of hydration of Portland slag cement is lower than OPC. Therefore, this cement can be used in mass concreting,
  • Higher resistance against the attack of chlorides and sulfate.
  • Better refinement of pore structure.
  • Higher water tightness, so this cement can be used in the marine structures.

​Rapid hardening cement:

• It is the type of cement that developed a higher rate of gain of strength and must not be confused with quick setting cement which only set quickly.
• The cement attains the strength at the age of 3 days equivalent to that attained by OPC in 7 days.
• This Higher strength in the initial stage is attributed to the higher fineness of the cement and increases the proportion of C 3 S ( specific surface area should not be less than 3250 cm 2 /gm and C 3 S is approximate 56%).
• Application
  • Pre-fabricated construction
  • Cold weather concreting
  • Emergency repair work
  • Pavement construction

High alumina cement:

• This cement is obtained by fusing a mixture, in suitable proportions, of alumina and calcareous materials and grinding the resultant product to a fine powder. The raw material used for the manufacture of high alumina cement is limestone and bauxite,
• The proportion of alumina in the cement must not less than 32% and the ratio of the percentage of alumina to that of lime is in the range of 0.85 to 1.3.
• The cement offers a higher initial setting time (3.5 hours) and a lower final setting time (5 hours), hence more time is available to work with the cement along with speedy construction.
• The cement can also resist high temperatures,
• It can resist the action of acid up to a greater extent.
• It also offers a higher rate of gain of strength.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students What consistency of cement paste is required to calculate the initial setting time?

1. Concept:
2. Normal consistency test:
3. Standard consistency is the consistency of the cement paste that permits the Vicat’s plunger of diameter 10 mm and height 50 mm to penetrate into the mold up to a depth of 33 to 35 mm from the top.
4. In the normal consistency test we have to find out the amount of water to be added to the cement to form a cement paste of normal consistency.

Type of test	Water Content
Initial and Final Setting Time	0.85p
Compressive Strength	p/4 + 3
Tensile Strength	p/5 + 2.5
Soundness Test	0.78p

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Which of the following is NOT an advantage of using composite cement lime mortar over cement mortar?

1. High workability
2. High water retention
3. Low drying shrinkage
4. High drying shrinkage

Option 4 : High drying shrinkage Concept:­ Lime-Cement Mortar:

• Also known as Gauged mortar.
• It is made from cement and lime.
• The advantages of lime-cement mortar are increased Water retentivity, workability, bonding properties and frost resistance,
• This mortar gives good and smooth plaster finish and is used in buildings.
• Mix proportions are given below-

Location	Ratio (by volume) (Cement : Lime : Sand)
Outside walls	1 : 1 : 6 to 1 : 2 : 9
Inside walls	1 : 2 : 9 to 1 : 3 : 12

Note:- Since presence of lime increases the water retentivity in cement. This presence of water reduces the shrinkage of cement upon drying. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students : Cement MCQ – Objective Question Answer for Cement Quiz – Download Now!

Which apparatus is used for testing setting time of cement?

Free Gujarat Engineering Service 2019 Official Paper (Civil Part 1) 150 Questions 150 Marks 90 Mins The setting time of cement is of two types: 1) Initial Setting Time: It is defined as the time elapsed between the moments when water is added to the cement, to the time when the cement paste starts losing its plasticity.2) Final Setting Time: It is defined as the time elapsed between the moments when water is added to the cement, to the time when the cement paste has completely lost its plasticity.

Apparatus	Test
Le Chatelier apparatus	Soundness
Briquette testing apparatus	Tensile strength
Vicat apparatus	Consistency, Initial and final setting time
Casagrande’s apparatus	Liquid limit determination

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The finally selected candidates will get a salary range between Rs.53100 to Rs.208700.

Which apparatus is generally used to measure the soundness of the cement Mcq?

Free RSMSSB JE General Knowledge Free Mock Test 10 Questions 10 Marks 8 Mins Explanation: Expansion of cement is measured/computed by soundness test. Soundness means the ability to resist volume expansion and it is indication durability. The unsoundness in cement is due to the presence of an excess of free lime than that could be combined with acidic oxide at the kiln.

The Le-Chatelier test detects unsoundness due to free Lime only. This method of testing does not indicate the presence and after effect of the excess of magnesia. As per Indian Standard specification, if the content of magnesia is greater than 3% in cement then Autoclave Test is performed which is sensitive to both Lime and Magnesia.

Last updated on Sep 22, 2022 The DV Dates for the RSMSSB JE (Agriculture) have been announced. The DV will be conducted on the 9th and 10th of November 2022. Earlier, the RSMSSB JE Result, Final Answer Key, Cut Off were released for written examination on 14th October 2022.

What is autoclave test of cement?

The autoclave expansion test (ASTM C 151) is used to provide an index of potential delayed expansion caused by the hydration of CaO and MgO in hydraulic cements. Questions have arisen over the years regarding the effect of excess crystalline free MgO (periclase) on cement soundness and concrete durability under actual service conditions.

It has been suggested that the autoclave expansion test is overly severe and will exclude cements that perform well in concrete under field service conditions with no reduction in long-term durability. Other experimental protocols and tests for soundness have also been developed and investigated over past years, including an update of the Le Chatelier Soundness Test and a number of other modifications in testing temperatures and time of testing.

Chemical compositional influences on periclase formation and the resistance of cement or concrete to expansion have also been identified. The purpose of this literature review is to update and supplement previous reviews on this topic.

Record URL:

http://www.cement.org/bookstore/download.asp?mediatypeid=1&id=6439&itemid=SN2651

Corporate Authors: Portland Cement Association 5420 Old Orchard Road Skokie, IL United States 60077 Authors:

Klemm, Waldemar A

Publication Date: 2005

Which test is used for soundness of cement?

1. objective – It is very important that the cement after setting shall not undergo any appreciable change of volume. Certain cements have been found to undergo a large expansion after setting causing disruption of the set and hardened mass. This will cause serious difficulties for the durability of structures when such cement is used.

1. The unsoundness in cement is due to the presence of excess of free lime than that could be combined with acidic oxide at the kiln.
2. It is also likely that too high a proportion of magnesium content or calcium sulphate content may cause unsoundness in cement.
3. 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.

Why is soundness test done for cement?

3.4.8 Soundness – The soundness test determines an aggregate’s resistance to disintegration by weathering and, in particular, freeze–thaw cycles ( AASHTO T 104, 2003 and ASTM C88, 2013 ). The test is carried out by repeated immersion in a saturated solution of sodium or magnesium sulphate followed by oven drying to partially or completely dehydrate the salts precipitated in the permeable pore space.

The data available ( Gorai et al., 2003; Shi et al., 2008; Song, 2013 ) suggest that the reported soundness measurements of 0.8–0.9% for CS are well below the maximum permissible limits of 15–25% for hot mix asphalt surface course, structural concrete made with marine limestone ( BS EN 12620:2002+A1, 2008; BS EN 13242:2002+A1, 2007; SCDOT, 2011 ).

Thus, it may be concluded that CS is a perfectly sound material for use in construction. Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780081009864000031

How do you use Vicat apparatus?

Procedure: –

1. In order to prepare a sample in mould, we need to take 400 gm of cement passed through an 850-micron IS sieve.
2. Add 100 ml of water to it. While adding water it should be kept in mind that gauging time (time of adding water until we start filling the mould with paste) is between 3-5 minutes.
3. Rest the mould on a non-porous plate and fill it with the paste prepared. Tap the mould to remove any bubbles of air.
4. Place the mould along with the plate under the rod and plunger attached with the apparatus.
5. Lower the plunger gradually till it touches the surface of the mould and then releases it quickly.
6. Prepare similar moulds with varying quantities of water and test in a similar way to find standard consistency.

Why is the consistency of cement determined?

Consistency of Cement Meaning – The consistency of cement paste is defined as the percentage of water requirement of cement paste at which the viscosity of paste in such a way that it determines the amount of water needed to make a paste. It is necessary to determine consistency because the amount of water affects the setting time of the cement,

What is Vicat test of cement?

One of the most common ways to assess cement consistency is with a Vicat apparatus. This machine is used to determine the standard consistency of a cement paste, as well as its initial and final setting time.

What is plunger in Vicat apparatus?

• Rigid frame construction for accurate readings. • Reversible plunger with removable needle. • Includes needle and hard rubber mold. The Vicat Apparatus is designed for determining the normal consistency, standard consistency and time of setting of cement and lime in accordance with ASTM and AASHTO specifications.

What is Vicat needle test?

Applications The Vicat test is used for testing materials that have no real melting points. The main principle is that it measures the temperature at which a flat ended needle is able to penetrate the sample. This is known as the softening point of the material.

Without the input of an operator, this machine saves time without sacrificing precision and accuracy. The machine is designed to automatically apply the force to the sample while it records the depth of the needle. Just press a button and wait for the results! This unit allows for further time saving by performing the same test 6 times simultaneously.

The Vicat tester is a PC-controlled unit equipped with software running on the Windows operating system.

How do you measure consistency?

Cronbach’s alpha – Internal consistency is usually measured with Cronbach’s alpha, a statistic calculated from the pairwise correlations between items. Internal consistency ranges between negative infinity and one. Coefficient alpha will be negative whenever there is greater within-subject variability than between-subject variability.

Cronbach’s alpha	Internal consistency
0.9 ≤ α	Excellent
0.8 ≤ α < 0.9	Good
0.7 ≤ α < 0.8	Acceptable
0.6 ≤ α < 0.7	Questionable
0.5 ≤ α < 0.6	Poor
α < 0.5	Unacceptable

Very high reliabilities (0.95 or higher) are not necessarily desirable, as this indicates that the items may be redundant. The goal in designing a reliable instrument is for scores on similar items to be related (internally consistent), but for each to contribute some unique information as well.

Note further that Cronbach’s alpha is necessarily higher for tests measuring more narrow constructs, and lower when more generic, broad constructs are measured. This phenomenon, along with a number of other reasons, argue against using objective cut-off values for internal consistency measures. Alpha is also a function of the number of items, so shorter scales will often have lower reliability estimates yet still be preferable in many situations because they are lower burden.

An alternative way of thinking about internal consistency is that it is the extent to which all of the items of a test measure the same latent variable, The advantage of this perspective over the notion of a high average correlation among the items of a test – the perspective underlying Cronbach’s alpha – is that the average item correlation is affected by skewness (in the distribution of item correlations) just as any other average is.

1. Thus, whereas the modal item correlation is zero when the items of a test measure several unrelated latent variables, the average item correlation in such cases will be greater than zero.
2. Thus, whereas the ideal of measurement is for all items of a test to measure the same latent variable, alpha has been demonstrated many times to attain quite high values even when the set of items measures several unrelated latent variables.

The hierarchical “coefficient omega” may be a more appropriate index of the extent to which all of the items in a test measure the same latent variable. Several different measures of internal consistency are reviewed by Revelle & Zinbarg (2009).

What is consistency of a measuring instrument?

RELIBILITY – is the consistency of your measurement, or the degree to which an instrument measures the same way each time it is used under the same condition with the same subjects. In short, it is the repeatability of your measurement.

What is consistency in measurement called?

Key Takeaways –

• Psychological researchers do not simply assume that their measures work. Instead, they conduct research to show that they work. If they cannot show that they work, they stop using them.
• There are two distinct criteria by which researchers evaluate their measures: reliability and validity. Reliability is consistency across time (test-retest reliability), across items (internal consistency), and across researchers (interrater reliability). Validity is the extent to which the scores actually represent the variable they are intended to.
• Validity is a judgment based on various types of evidence. The relevant evidence includes the measure’s reliability, whether it covers the construct of interest, and whether the scores it produces are correlated with other variables they are expected to be correlated with and not correlated with variables that are conceptually distinct.
• The reliability and validity of a measure is not established by any single study but by the pattern of results across multiple studies. The assessment of reliability and validity is an ongoing process.

What is consistency of a measuring instrument?

RELIBILITY – is the consistency of your measurement, or the degree to which an instrument measures the same way each time it is used under the same condition with the same subjects. In short, it is the repeatability of your measurement.

What are measures of consistency?

Key Takeaways –

• Psychological researchers do not simply assume that their measures work. Instead, they conduct research to show that they work. If they cannot show that they work, they stop using them.
• There are two distinct criteria by which researchers evaluate their measures: reliability and validity. Reliability is consistency across time (test-retest reliability), across items (internal consistency), and across researchers (interrater reliability). Validity is the extent to which the scores actually represent the variable they are intended to.
• Validity is a judgment based on various types of evidence. The relevant evidence includes the measure’s reliability, whether it covers the construct of interest, and whether the scores it produces are correlated with other variables they are expected to be correlated with and not correlated with variables that are conceptually distinct.
• The reliability and validity of a measure is not established by any single study but by the pattern of results across multiple studies. The assessment of reliability and validity is an ongoing process.

How do you measure consistency of a test?

Test-Retest Reliability – Test-retest reliability is a measure of the consistency of a psychological test or assessment. This kind of reliability is used to determine the consistency of a test across time. Test-retest reliability is best used for things that are stable over time, such as intelligence,

Test-retest reliability is measured by administering a test twice at two different points in time. This type of reliability assumes that there will be no change in the quality or construct being measured.   In most cases, reliability will be higher when little time has passed between tests. The test-retest method is just one of the ways that can be used to determine the reliability of a measurement.

Other techniques that can be used include inter-rater reliability, internal consistency, and parallel-forms reliability. It is important to note that test-retest reliability only refers to the consistency of a test, not necessarily the validity of the results.

How do you measure the consistency of food?

Stirring a fluid or semifluid food with a spoon or a finger is frequently used by consumers to give an indication of viscosity or consistency.