Abstract
Reuse of waste fresh concretes can contribute the resource saving and control of industrial wastes emission. Addition of a suger set-retarding agent and a superplasticizer to the waste fresh concrete and subsequent wet-screening resulted in the Eco mortar, for which an applicability to the preceding mortar for concrete pumping constructions was studied. It was shown through the experiments of setting, fluidity and compressive strength that the appropriate amount of the chemical admixture to meet the requirements can be determined as a function of ambient temperature and the Eco mortar can be used in the next day or later. Full-scale concrete pumping experiment using the Eco mortar as a preceding mortar was conducted in a ready-mixed concrete plant and a pumping efficiency equivalent to the 1 : 3 mortar was obtained.
