| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 103 === The volume of aggregates occupies by more than 70 vol. % of concrete. The packing problem of aggregates has a decisive influence on concrete quality, The concrete which is made by a good packing condition will have a better performance on all aspects of strength, permeability and economy, etc. . Most previous researches use experimental method to get the mixing proportion with maximum packing density of aggregates in order to reach the goal of dense grading.
This study, used the compressible packing model (CPM) which has proposed by the scholar de Larrard in 1999 to calculate the packing density of aggregates, and compare that from the analysis of Fuller's curve with two different parameters. Simultaneously, the local sand and gravel were sieved into five different combinations of aggregate packing, including five-phase aggregates (all of fine aggregate), six-phase aggregates (five-phase aggregates +#4 coarse aggregate, +3/8" coarse aggregate and +3/4" coarse aggregate), eight-phase aggregates (all of fine aggregate +3 kinds of coarse aggregate),together with three kinds of gradation mode to conduct a total of 15 different sets of experiments for packing density test in order to verify the results of numerical analysis.
The results show that, in consideration of the wall effect and loose effect, the mean packing densities for five different combinations of aggregate mixtures calculated by the CPM were higher than those of ten groups of aggregate mixtures obtained by the Fuller's curve by 2% ~ 10%. In the meantime, most experimental results of packing density for those fifteen groups of mixtures were located between two analytical results. The difference of packing density obtained by two kinds of Fuller's curve was less than 7%. The mean packing density of 8-phase aggregate with three packing modes were between 0.677 and 0.721. On the other hand, the mean experimental packing densities of 5-phase aggregate were between 0.770 and 0.827, were between 0.715 and 0.724 for 5-phase aggregate. It indicates that, under the premise of no excessive interference among aggregates that proposed CPM can have the usability and feasibility to build the well-made article packing with different combinations of aggregates.
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