Field test on cement at construction site | Introduction of cement। Field test on cement। Field test for cement | field test of cement | check the quality of cement at site.
Cement is one of the most important building material or backbone of concrete, used as Binder to hold all ingredient of concrete material cement sand
Regarding this, “field test on cement”, field tests are easy to perform at the construction site which are carried out to ascertain the vertue of cement supplied within a short period of time but difficult to understand.
In simple word field test on cement is basic needs to check the quality of cement on construction site at the time of initial inspection to know some idea about the quality of cement. Lab tests are difficult to perform at the construction site in a short period of time for evaluating the condition of supplied cement in initial inspection.
But these tests are easy to understand, so performing field test on cement at the construction site in short period of time for checking the quality of cement to improve functionality and performance of initial providing cement.
Field tests for cement performs to determine the physical properties of cement, to regulate the various stages in manufacturing process as a slight difference in the process of manufacture of cement may cause a great difference in the property of cement and very useful to understand the behaviour of cement after its use on the works and also this test is carried out to determine the strength of cements.
Field test on cement
Field test on cement is basic needs to check the quality of cement on construction site at the time of initial inspection to know some idea about the quality of cement. Lab tests are difficult to perform at the construction site in a short period of time for evaluating the condition of supplied cement in initial inspection.
Field test on cement at construction site are following:-
1. Colour of cement
2. Manufacturing date of cement
3. Adulteration test
4. Presence of lumps
5. Float test
6. Temperature test
7. Set test
8. Strength test – (a) compressive strength test, and (b) tensile strength test
Colour of cement
Regarding this, the colour of cement should be uniform, grey colour or greenish shade, in fact that grey colour of cement is an indication of pure variety of cement and the colour of cement also indicates the presence of excess of clay or lime and a burning of degree. Sample of cement under consideration should posses uniform grey colour within a bag.
Manufacturing date of cement
Regarding this, manufacturing date of cement, cement should be used within three months ( 90 days) from its production date for construction structures, we should be check the manufacturing date of cement, due to in fact that the strength of cement reduces in respect to increased in manufacturing date of packing, in simple word it means the strength of cement is inversely proportional to manufacturing date of cement.
After three months it’s strength is reduced by 20-30 percent, after six months strength is reduced by 30-40 percent and as much as 40-50 percent after 12 months, after 1 year cement is unsuitable for use of construction structures.
Finally it’s decided to cement strength as good as fresh till three months when stored as per the guidelines and sealed in a impermeable bag, it’s stored environment should not be absorbs moisture,hydrates. However, if it is stored more than 3 months the strength of cement should be tested before using it in short period.
Regarding this, Adulteration test, it mean adding non cement materials or addition of other components to the cement that changes their standard chemical composition in contrast to changes like colour, texture, this test is done by toching the cement by fingers.
if small quantity of cement is pinch feel rub between the fingers, it should be feel smooth, feel cool, if it feel rough, in a simple means that the cement is adulterated with sand or furnace ashes. So in case of adulteration test is perform sample must feel cool and not warm when sensed by inserting hand in the cement sample.
Presence of lumps
Regarding this, Presence of lumps test, presence of lumps are formed due to high moisture content or high humidity in the area of storage of cement, it is give a problem with OPC cement silo. Serious troubles started during operation of packing plant, caused by the formation of cement lumps, entry of humid air, lack of venting, temperature of cement are the reasons for lump formation.
Sample should be free from presence of air set lumps and should always be stored in a cool or dry area, in fact that lump formation in cement sample, any bags that are delivered to the construction site with lumps must be rejected. So open the bag and take a look at the cement, there should be no visible lumps.
Regarding this, Float test, this test is physical properties of cement, if a small quantity of cement sample is thrown in a bucket of water, it should sink and should not float on the surface.
Regarding this,Temperature test , this test is a important and necessary test to use in short period of time in construction site to decide the cement is good quality in inspection of cement properties. When we insert hand in bag of of cement or sample of cement ,then it should give cool feeling that must be cold from the inside of sample, if we are feeling hot from the inside of sample that is indicate the process of hydration of cement is taking place ,due to effectively sample need to check the temperature of cement before use the cement in construction site in initial time for inspection of cement.
Regarding this, Set Test, take a thick paste of cement with water is made on a glass plate and kept in water for 24 hours ,then it should be set and not shows crack, too much of set indicates the good quality of cement. Hydraulic cement is capable of setling under water and it’s virtue of setling ability under water is gain the strength .
The water added to the cement will leads to evaluation of heat,the cement components the C3S, and C2S reacts with water during hydration to form a calcium hydrates along with set and responsible for good properties of cement concrete, which is having binding properties, in fact that it is not show crack.
Regarding this, Strength test, this test is important Field test on cement which is involved a block or brequtte of size 25mm x 25mm x 200mm from given sample of cement and prepared by cement :sand /1:6 ratio, this block is immerse it in water for 7 days, then remove the block from water ,this should not break easily and should not be converted into powdered form, place over supports having spacing of 150mm and apply 340N central point load of specimen, the sample should not show any sign of failure under the loading. If the block will show no failure, the cement is of good quality.
Compressive Strength Test
Compressive strength test is the the must important test for hardened cement because cement is best in compression handling, take cement and standard sand in the proportion of 1:3 for prepare motar and water is added in the proportion of ( p/4)+3 percent. Then fill the mortar in 5000 mm2 area. Mould is immersed in water for sufficient duration for curing.
Temperature and humidity condition should be 27 degree Celsius and 90 percent respectively, strength should be tested for 3 days,7 days and 28 days.
Sample is tested in UTM (universal testing machine) and apply a gradual load of 35 N/mm2/minute, An average of 3 results for each age is taken as Compressive strength of cement for that age .
Compressive strength of 33 grade of OPC is following-
1. Days 3, Compressive strength 16 MPa
2. Days 7, Compressive strength 22 MPa
3. Days 28, Compressive strength 33 MPa
Tensile Strength Test
Regarding this, Tensile strength test, this test is repeating by the same process for preparing motar in compressive strength test , this test is the only difference is the water added is (p/5)+2.5 percent and spacimen is subjected to any form having tensile stress of 3.5 N/mm2/minute till failure, we have take an average of 12 result in this case as tensile strength of cement.
Tensile strength and compressive strength is related to generally having the value of tensile strength is 10-15 percent of compressive strength.
1. Days 3, tensile strength 2 MPa
2. Days 7, Tensile strength 2.5 MPa
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How do you find the field test of cement?
Regarding this, how do you find the field of cement, field tests on cement easy to perform the test on construction site, performs to determine the physical properties of cement,to regulate the various stages in manufacturing process as a slight difference in the process of manufacture of cement may cause a great difference in the property of cement and very useful to understand the behaviour of cement after its use on the works and also this test is carried out to determine the strength of cements.
This test is find the field test for cement following –
1.The colour of cement should be grey , greenish and uniform within sample cement or a bag cement which is gives an indication of excess lime or clay and the degree of burning
2. Hand inserting into the cement bag ,then it is gives the smooth feeling.
3. It should be free from presence of lumps
4. a small quantity of cement sample is thrown in a bucket of water,it should sink and should not float on the surface.
5. we insert hand in bag of of cement or sample of cement ,then it should give cool feeling that must be cold from the inside of sample.
6. take a thick paste of cement with water is made on a glass plate and kept in water for 24 hours ,then it should be set and not shows crack
7. Strength of cement, the block having size 25mm x 25mm x 200mm will show no failure of test, the cement is of good quality.Compressive strength of cement increased for that increase age .