Hi Seyed,

I would suggest adding some amount of limestone powder, it will improve the density of the mortar and also the workability, and therefore will allow you to decrease the water-to-binder ratio a bit more. It will also be advantageous from the point of view of powders compatibility with chemical admixtures, and probably you will be able to decrease the w/b ratio even further by increasing the SP dosage without risking segregation or sedimentation issues.

All the best.

the admixture with high water absorption like SF could be useful as well

Hi Seyed,

I would suggest adding some amount of limestone powder, it will improve the density of the mortar and also the workability, and therefore will allow you to decrease the water-to-binder ratio a bit more. It will also be advantageous from the point of view of powders compatibility with chemical admixtures, and probably you will be able to decrease the w/b ratio even further by increasing the SP dosage without risking segregation or sedimentation issues.

All the best.

Rather than formuatate mortars with Portland cement, use  a high early strength cement type such as calcium sulffoaluminate or calcium  aluminate cement..

Steam curing. In fact steam curing is a process for hardening concrete, cement, and mortar that involves exposure to warm steam.

TANX for all comments. After some experimental studies on different techniques, I found the heating technique pretty effective to increase 1-day strength of cementitious mortars. In fact a minor increase on curing temperature (from 15 degrees to 25 degrees) can greatly contribute to early strength.

Using the W/C ratio of 0.35 in a self consolidating cement mortar, cured at 25 degrees, we achieved a mortar with 1-day compressive strength of more than 20 MPa.

Dear Dr Amin the results was very amazing, thanks for share your results

I would suggest to add the microsilica to your mixture. It can help your paste be more powerful than before. In one of our experiments, we exactly compared the specimen with and without the microsilica and the effect of microsilica became of strong factor for high early strength of the paste. 

Please let me know if you have any further questions.

How could addition of extra silica in the form of mineral admixtures (such as microsilica, rice husk ash, etc) contribute to early strength of concrete (at 3-7 days) as few papers reported that silica from mineral admixtures react with calcium hydroxide generated after hydration reaction of cement with water? Addition of silica improved the strength at 28 day and so on.

Please comment.

Thanks

There are some contradictional reports within the literature. Most earlier studies suggested that silica fume has a negative effect on the early strength. In my own experimental program, I have measured reduced early strengths due to silica fume. In other hand, I've seen some studies suggested that silica fume had increased the early strength....! It seems there is no uniform picture about this story yet.