Dear Hammad,

Please provide more details. What was the air temperature and humidity during casting? It may help in the interpretation.

Best regards

Łukasz Sadowski

Dear Hammad,

Higher Cement content in a given mix may lead to shrinkage of concrete. In your case, Higher cement content with higher dosage of admixture is tried for getting more strength. But it looks that during over compaction cement slurry is raised at top by capillary rise and after drying shrinkage cracks are appeared at top surface. You have not mentioned about workability and strength of concrete. Water cement ratio is very less and if your are getting more workable concrete at higher dosage of admixture, then cracks are due to higher cement content and reduction in surface water content .

Thanks for your reply.

@Lukasz Sadowski I did not monitor the indoor temperature. But outdoor temperature was 23 degree Celsius while humidity was 66%. So indoor temperature may be in range of 20 degree Celsius and humidity in the range of 60 to 70%.

@ Ishwar Sonar flow table test gave value of 210 mm, while target 7 days strength is more than 100 MPa, which is yet to be determined after 2 days.

There appears to be volume expansion reactions occurring after mixing. What type of cement did you use? What is the chemical composition of the silica fume and that of the cement? Any contaminations in the materials used? Is the admixture compatible with the cement ?

Either there is a higher cement content or less bond - binder is not adequate or silica fume is no t proper or temperature ambient is quite high.

I agree with @Mittal. These may be reasons of it since the curing conditions were fine

provide us with the quantities of concrete ingredients