Amino Acid Series Superplasticizer Ah Development And Reducing Water

By analyzing some polar groups, a high-range water-reducing agent AH is designed. AH is sulfonic acid series superplasticizer by condensation of p-amino-benze sulfonic acid, phenol and formaldehyde. Some factors affect the synthetic process such as dosage of the reaction materials, the put materials' sequence, reaction time, temperature and the pH value of the solution. By studying these factors, we find the optimum conditions are: the ratio of the amount of p-amino-benze sulfonic acid to the amount of phenol is 1/2, the ratio of the amount of both p-amino-benze sulfonic acid and phenol to formaldehyde is 1:1.15～1.3; the pH value in this step is 7～10; the reaction temperature is 75℃～95℃; the reaction density is 35%; the reaction time is about 5 hours; the put materials' sequence is the p-amino-benze sulfonic acid and phenol ahead; when urea is also added in the synthetic process, the fluidity of cement paste can be raised, and the cost may be reduced.The research on the surface physico-chemical properties of AH shows that AH reduces surface tension little, has low foaming capacity and small foaming-stabilization time. It has been deduced that AH belongs to non air-entraining high-range water-reducing agent. The study to the reaction time indicates that by adding the urea into the reaction system ,the fluidity of cement paste has little variation with the time and the synthetic technology has widely applicability.steric hindrance, partial electrostatic repulsive force and adsorbing lubricating function of AH contribute to its better dispersing performance. comparing with the widely-used high-range water-reducing agent FDN, AH can render cement paste with higher fluidity and has better water-reducing property. AH also has better flow ability retention. The fluidity of cement paste using 0.45% AH after 90 minutes loses only 14.7%, while that of 0.45% FDN after 90 minutes unexpectedly loses 100%. In addition, AH has setting-retarded effect, But it doesn't affect the early compressive strength of cement motar. The great dispersing effect and high water-reduction effect of AH make the hydration reaction of cement particles more sufficient and therefore the concrete structure is denser. It also helps to enhance the compressive strength of cement mortar greatly. The compressive strength of the cement mortar prepared using AH after 3days is increased a little, but the compressive strength after 7days and 28days is increased remarkably. So AH is the ideal high-range water-reducing agent for preparing high strength, super high strength concrete and High Property Concrete.