Abstract
Organic admixtures including fluidizing agent, air entraining agent and water-reducing agent are indispensable for manufacturing high-performance multi-functional concrete. However, various phenomena concerning the setting and hardening of concrete caused by the addition of admixtures are at present dealt with by symptomatic measures without any elucidation of the causes because the working mechanism have hardly been clarified yet. Using the samples prepared by mixing β-naphthalenesulfonic acid-and lignin sulfonic acid-based organic admixtures, and by dipping the polished surface of clinker into the water containing admixture for a specified time, the effect of the adsorption of admixture on the hydration of cement and the adsorptive behavior of admixtures were examined and the relationships of them with the physical properties of fresh paste including fluidity, variation of fluidity with time and setting time were discussed with the advanced method of micro surface characterization such as in-lens FESEM, ESCA-imaging AES and AFM to elucidate the cause of phenomena observed in concrete containing organic admixtures.
