dc.description.abstract | The purpose of this study was to evaluate the method of the modified artificial aggregates (MAA) used in low-level concrete and the practical market positioning strategy. The practice of this research can be divided into three experimental stages: preparation of modified artificial aggregates, analysis of material properties, and the mix of modified artificial aggregate concrete.
The results show that: (1) The suitable w/s ratio of granulating for manufacturing modified artificial aggregates is 0.27 to 0.33, the molding method of MAA is more effective by pressuring and vibrating at the same time. (2) The properties of MAA compared to that of the natural aggregates with lighter specific gravity, higher water absorption and abrasion rate, however, the soundness, the sand equivalent value and the potential expansion of aggregates from hydration reactions are in compliance with the regulations. (3) When the MAA to replace natural aggregates, the initial workability can meet the demand, however, for specimen using slag replaces 40% cement by weight, the slump loss condition of 30 minutes is not improved. The amount of concrete expansion has not been improved and the compressive strength has not been increased, but the amount of dry shrinkage can be reduced effectively. (4) The slump loss of 30 minutes for the MAA concrete is less than that of concrete using the manufactured sand of waste concrete blocks, and has the lower value of the shrinkage rate, but for the compressive strength, there is no significant difference between the two. (5) Whether adding slag or fly ash, w/b ratio of 0.66,0.70 and 0.90, MAA replace natural fine aggregates of 50% and 100%, the compressive strength of specimens all can meet the target strength of 80 - 210 kgf/cm2. | en_US |