Development of Utilization Methods of Various Stages for Ready-Mixed Concrete Wastes

从环境保护的角度来看，混凝土污泥的处置已成为一个大问题，本研究主要探讨了以下三个阶段的利用方法：(1)混凝土污水浓度控制的现场试验(阶段：回用)考虑到混凝土污泥的利用，在处置污泥的混凝土厂内，利用污泥水进行混凝土搅拌似乎是最好的方式。为了保证混凝土厂污泥的资源化利用，保证污泥水中污泥颗粒的浓度是非常重要的。然而，当污泥水中含有大量非常细的集料和污泥颗粒时，准确测量污泥颗粒的浓度被认为是相当困难的。提出了一种采用虹吸式旋风除尘器的新型污泥浓度稳定系统。此外，他们还进行了现场试验，以检验所提出的系统的有效性。(2)从商品混凝土厂排出的干燥颗粒混凝土污泥(阶段：循环)的基本性质通常是脱水成含有一定水分的泥饼。然而，与干燥的污泥相比，污泥饼的处理相当困难。本研究通过一系列的试验研究了制备干泥的热处理工艺和外加剂(硅酸盐水泥、水磨铁矿渣、石膏)的影响，研究了干泥的造粒工艺、储存过程中的碳化过程以及水渣细度对干泥砂浆强度发展的影响。(3)将干泥用作混凝土外加剂(阶段：循环)。

Disposal of concrete sludge has become a big problem from the viewpoint of environmental conservation, In the present study, mainly following three stages of utilization methods are examined.(1)FIELD EXPERIMENT ON CONSENTRATION CONTROL OF CONCRETESLUDGE WATER (Stage : Reuse)Considering the utilization of concrete sludge, it seems to be basically the best way to use sludge water for the mixing of concrete within a concrete plant from which the sludge is disposed. For the reuse of concrete sludge in the concrete plant, it is very important to assure the concentration of sludge particles in a sludge water. Accurate measurement of the concentration of sludge particles, however, is considered rather difficult when a large amount of very fine aggregate is contained together with sludge particles in a sludge water. The authors have proposed a new type of sludge-concentration-stabilizing system in which a siphon-type cyclone apparatus is incorporated. Also, they have carried out a field experiment to examine the effectiveness of the proposed system.(2)FUNDAMENTAL PROPERTIES OF DRIED GRANURATED CONCRETE SLUDGE(Stage : Recycle)Concrete sludge discharged from ready mixed concrete plant is usually dehydrated to be sludge cake which contains water to some extent. However, the sludge cake is rather difficult to be handled compared with dried sludge. In the present study, followings have been examined in a series of experiments : firstly the effects of heat treatment in making dried sludge, and of admixtures (Portland cement, water granulated iron-blast-furnace slag, gypsum) ; secondly the effects of granulation process in making the dried sludge, of it's carbonation in storage, and of fineness of water granulated slag as admixture on strength development of mortar with the dried sludge.(3)UTILIZATION OF DRIED CONCRETE SLUDGE AS ADMIXTURE IN CONCRETE(Stage : Recycle)It was found that the dried sludge can be used as an admixture in concrete.