I am looking for an early hardening 8 to12 hrs with low alkali Ordinary Portland Cement using pce superplasticizer. Which organic compound can have a synergistic action. I have tried alkanol amines but results are not so effective.
Difficult, as most organics retard. Alkanol amines are not very efficient regarding acceleration. I suggest using Ca salts as hardening accelerators such as calcium nitrate or calcium formate. Of cause you can accelerate as well with alkali sulfates, but this is probably not intended as you are using a low alkali cement.
Regarding the PCE - you should use a product suitable for precast concrete, which generally retards less than products for readymix concrete. Try not to overdose the PCE.
I agree with @Frank Winnefeld, a good start is to retard less by using a lower superplasticizer dosage. This dosage decrease may occur if you use a calcium based accelerator, especially if you have a high soluble sulfate cement.
I do not understand why you wish to stick to organics, unless it is for formulating into the PCE. They have the bad habit to have a narrow dosage range of efficiency, and may delay hydration if overdosed.
TIPA also entrains a bit of air, and that could decrease strength. Have you ever tested glycerin?
Thanks for your answer. I have used TIPA Ester with carboxylic acid incorporated in the PCE molecule during manufacturing. My findings were
lower dosage is advisable
AEEA ester and other alkanol amine esters are good for hardening after 24 hrs.
Molecule of PCE is important If we can have High Mol wt. Ether about 5000 and above mol. then hydration is controlled remarkably.
I am still working for early strength. If you have suggestion then please guide me.
As such glycerol is not tried but glycerol phosphate has been tried. The results relates to the percentage use by wt. of admixture. Upto 6%is optimum
Longer PEO chain can be combine with hydrofobic group to reduce airentrainment in concrete. The long chain helps in enveloping cement paste and hydration is accelerated inspite of low temp. Amine esters are more favourable then amine alone.
CSH nano particles are effective but dosage is 2 to 3%,
I am looking for additive to be blended with PCE molecule so that dosages are not very high. Low mol wt. are more effective then High mo. Wt.
Pyrocatechol (1,2-dihydroxybenzene) is a very effective accelerator for OPC and retarder for CAC in small dosages.
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