| 摘要 |
PURPOSE:To increase initial strength of a cement.concrete hardened body by adding an alkali compound to a kneaded material during the period from the start of kneading to the time of starting the work after the specified time has passed, re-kneading and then cast injecting or placing the same in the field. CONSTITUTION:A kneaded material of 0.5 water-cement ratio or under manufactured by kneading cement, an aggregate and water is cast or field placed to manufacture a cement mortar. concrete hardened body. An alkali compound is added therein during the period from the start of kneading of concrete to the starting time of the work after 30 minutes or more has passed, re-kneaded and then cast or field placed. In the case that the adding period of alkali compound is started in less than 30 minutes, sometimes the adding effect is not recognized which is not preferable. In the case that the adding and kneading is carried out after the proper starting time of work, aggregation is already in progress and the kneaded material is not uniform and also its strength is lowered which is not preferable either. Also, the alkali compound should be added to the kneaded material having 0.5 water/cement ratio or less. In the case of being beyond 0.5, adding effect is low and not preferable. |
