Awarded as the best online publication by CIDC

Tests Conducted To Check Quality Of Concrete

Test conducted on site for quality control

Slump test
This is a site test to determine the workability of the ready mixed concrete just before its placing to final position inside the formwork, and is always conducted by the supervisor on site. However in mid of concreting process , should the site supervisor visually finds that the green concrete becomes dry or the placement of concrete has been interrupted , a re-test on the remaining concrete should be conducted in particular of the pour for congested reinforcement area . The procedure of test in brief is as follows: –

1. Ensure the standard Slump Cone and associated equipment are clean before test and free from hardened concrete.
2. Wet the Slump Cone and drain away the superfluous water.
3. Request the mixer or concrete truck to well mix the concrete for additional 5 minutes.
4. Place the Slump Cone on one side ( i.e. not in middle ) of the base plate on leveled ground and stand with feet on the foot-pieces of cone .
5. Using a scoop and fill the cone with sampled concrete in 3 equal layers, each of about 100mm thick.
6. Compact each layer of concrete in turn exactly 25 times with a Slump Rod, allowing the rod just passes into the underlying layer.
7. While tamping the top layer, top up the cone with a slight surcharge of concrete after the tamping operation.
8. Level the top by a “sawing and rolling” motion of the Slump Rod across the cone.
9. With feet are still firmly on the foot-pieces, wipe the cone and base plate clean and remove any leaked concrete from bottom edge of the Slump Cone.
10. Leave the foot-pieces and lift the cone carefully in a vertical up motion in a few seconds time.


11. Invert the cone on other side and next to the mound of concrete.
12. Lay the Slump Rod across the inverted cone such that it passes above the slumped concrete at its highest point.
13. Measure the distance between the underside of rod and the highest point of concrete to the nearest 5mm.
14. This reading is the amount that the sampled concrete has slumped.
15. If the concrete does not show an acceptable slump, repeat the test with another sample.
16. If the repeated test still does not show an acceptable slump, record this fact in the report, or reject that load of concrete.

Compression test
The Compression Test is a laboratory test to determine the characteristic strength of the concrete but the making of test cubes is sometimes carried out by the supervisor on site. This cube test result is very important to the acceptance of insitu concrete work since it demonstrates the strength of the design mix.
The procedure of making the test cubes is as follows: –

1. 150 mm standard cube mold is to be used for concrete mix and 100 mm standard cube mold is to be used for grout mix.
2. Arrange adequate numbers of required cube molds to site in respect with the sampling sequence for the proposed pour.
3. Make sure the apparatus and associated equipment ( see Fig 7 – 6 ) are clean before test and free from hardened concrete and superfluous water .
4. Assemble the cube mold correctly and ensure all nuts are tightened.
5. Apply a light coat of proprietary mold oil on the internal faces of the mold.
6. Place the mold on level firm ground and fill with sampled concrete to a layer of about 50 mm thick.
7. Compact the layer of concrete thoroughly by tamping the whole surface area with the Standard Tamping Bar. (Note that no less than 35 tamps / layer for 150 mm mold and no less than 25 tamps / layer for 100 mm mold).
8. Repeat Steps 5 & 6 until the mold is all filled. (Note that 3 layers to be proceeded for 150 mm mold and 2 layers for 100 mm mold).
9. Remove the surplus concrete after the mold is fully filled and trowel the top surface flush with the mold.
10. Mark the cube surface with an identification number (say simply 1, 2, 3, etc) with a nail or match stick and record these numbers in respect with the concrete truck and location of pour where the sampled concrete is obtained.


11. Cover the cube surface with a piece of damp cloth or polythene sheeting and keep the cube in a place free from vibration for about 24 hours to allow initial set .
12. Strip off the mold pieces in about 24 hours after the respective pour is cast. Press the concrete surface with the thumb to see any denting to ensure the concrete is sufficiently hardened, or otherwise de-molding has to be delayed for one more day and this occurrence should be stated clearly in the Test Report.
13. Mark the test cube a reference number with waterproof felt pen on the molded side, in respect with the previous identification number.
14. Place the cube and submerge in a clean water bath or preferably a thermostatically controlled curing tank until it is delivered to the accredited laboratory for testing.

Checking Quality of Fine Aggregates and Bricks
For checking the quality of fine aggregates, a field test was conducted in which the sand was placed in a flask containing water. The sand was allowed to settle for some time and then after few hours the reading of the silt or other impurity layer is takenIf that reading is less than 5% of the total sand that is put in the flask, then we accept the sand but if it is more than 5% the sand is rejected. Bricks were sent to the college laboratory for testing and thereby checking the quality of the bricks used at site.

Share this post

Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

If you have a query, you can ask a question here.

112 comments on "Tests Conducted To Check Quality Of Concrete"

panchal viral says:

1- How much time we are testing cube after receving incuring tank

Randhir Kumar Choudhary says:

one cube can be tested only one time. but we have the cluster of cube samples for a same concrete mix that we will be testing further.

milan says:

after 1 hour for dry the cube otherwise it may be failed due to wet

jimjananto says:

i want to know the definition and calculation of slump {grade m20 m15.and also the calculation of concrete cube test and definition of concrete get 15mm length and width

sanjay saxena says:

for cube test. we do test for 7 days and 28 days. if cube sterngth we aquire in 7 days, is it necessray to do 28 days cube test. for example for M-25. if cube strenth in 7 days is 19 N/Sqmm. is it necessary to do 28 days compressive strength test.

milan says:

yes it is required. because after 28 days result shoud get m 25 or more than and 15% exceed resuild is not consider

Dhruba Chhetri says:

if 7 day cube strength not passed and 28 day strength passed then there is any issue

raj says:

what is the maximum and minimum value of slump to be maintained

milan says:

maximum value 130 mm and minimum 60 mm

m.sreenivasa rao says:

i want results for cube test of concrete details

Praveen says:

70 to 100mm

idris jae says:

to me slump (workability) of conc depends on the intended method of placing the concrete in its final location. when using pump(boom placer), the slump may be btw 140-160mm and also when using a compressor(spot placing) it also varies.
best regards.

S. Morey says:

I am Asst. Lab Tech. in civil Pleased provide me the all(fine aggregate & Corse aggregate) soil testing information and calculation,farmula.

D.Rajesh says:

I am quality control supervisor in ready mix concrete please provide me the design mix details,specification of raw materials as per IS & testing methods & calculations ,

Appukkuttan says:

K300 Concrete cube 150x150x150 test report 7Days and 28Days. How much is the Max. and Min. streangth

milan says:

after 7 days u will get result 13.33 n/mm^2

idris jae says:

though i don’t understand what u mean by k300. i assumed u it is 30N/mm2. since cubes are cured under ideal condition, at 7days the cube is suppose to attain 70% of the design strength i.e 21N/mm2 and at 28days the target strength is suppose to be 30% higher than the design strength i.e 39N/mm2. All the best.

mohamad says:

I casted concrete when I testd cubic sample for 7 days given 2 Mpa instead of 14 , what is the reason bhind this

idris jae says:

the only reason is the use of inferior materials. 2N/mm2 is too bad.

paul says:

is there a certain number of cubes to be taken per cubic meter poured?

Shafeekh M says:

Yes Mr.Paul. As per IS 456:2000 page number 29 we have 2 take 1 sets of cubes for 1-5 CUM, 2 sets of cubes for 6-15 CUM, 3 sets of cubes for 16-30 CUM, 4 sets of cubes for 31-50 CUM..further for each 50 CUM of concrete add 1 set of cubes. A set of cubes containing total six number of cubes out which 3 sample of cubes are intended use for 7th day compressive strength test and remaining samples are intended use for 28th day compressive strength test.

Afuye Oluyemi Ibiyinka says:

pls i need the compressive strength of concrete and their corresponding mix ratio. plsssssssssssssssssssssssss

charles paul says:

by which BS standards is being used for testing cubes and procedures

charles paul says:

sir can you email me the correct procedure for testing cubes

nondumiso says:

I am a civil trainee.I am currently working for eskom in the new build power station but I need help.Could you kindly e-mail me all the correct procedure for testing cubes

arun says:

if cube should dried in oven before testing in CTM after removing curing tank . which is right ?

Asad jambughoda, Mehul Parmar says:

How many cubes sets should be casted for 50 cu.m of concrete As Per IS? and What is criteria for 0-100 Cu.m. concrete?

mohan says:

it is mentioned in IS 456

Ariel Dayton says:

I have received test results of for a cube 100x100x100mm which its design requirement is 35 N/mm2. The 7-day test results is showing 71 N/mm2. Is this normal? It sounds too high to me. Do you think the test hasn’t been done properly?

Zia ul Qamar says:

Dear Sir,
I am civil engineer, having problem while making concrete cylinders, it gives hney comb when the mould is removed, please advise how to avoid these honey combing.


g k kishore says:

For M-30 design mix concrete, after 28day result value for all the three cube in average is 30.14 N/ should be consider fail or pass in compression.

s.venkat rao says:

Dear Mr Kishore; First of all while taking sample we mix the concrete & then start taking cubes. Cubes taken are only a randome sample of that particular days Concrete pour. When we say M-30 it means all the cubes shall tested shall be not less than 30N/mm2.There is no any official avarage system. There are N number of reasons for failure of Concrete cubes. So considering the result AS fail, go for core cut of parent structure and crush it. if that also fails then you have no option than to REJECT THE STRUCTURE. S.Venkat Rao(Lead Quality Control Engineer-Civil & structures)

Fida Zaidi says:

Why Cube Compressive test is necessary and results

xenoMorf says:

its necessary because you can compare the actual grade with the required grade base on the project requirement.

Leave a Reply

Your email address will not be published. Required fields are marked *

Ask a question