| Guaranteeing the compaction quality of roller-compacted concrete(RCC) is the key to ensure the safety of RCC dam structures. The control criteria of compaction parameters which adapt to the variations of actual construction situations can provide the insurance for construction quality control at jobsite. Currently, the control criteria for construction procedures and parameters are mainly determined by the construction codes, engineers’ experiences and site experiments. However, the previous work does not analyze adequately the combined effect on compaction quality due to variations of multiple construction parameters and material properties. Thus the site-adaptive combined construction index and their control criteria that can reflect the compaction quality of RCC in real time are not available. It is significant for RCC quality control to establish real-time control index which can reflect the combined effect of multiple construction parameters and changing site situations. The main contents and achievements of this thesis include as follows:(1) A series of tests using a small-size compactor was carried out to analyze the compaction mechanism of RCC, which is based on the change regulation of RCC particle acceleration and surface settlement. And according to the analysis, the quantitative criterion for estimating the compaction was obtained.(2) The effects of each compaction parameter on RCC compaction quality were analyzed, and then the index of unit compaction power was proposed, which reflects the combined effect of compaction parameters. For the compaction quality control of RCC layer, the index of unit volume compaction power(UVP) was proposed and its correlation with compaction quality was also analyzed. As a result, the control criteria can be determined according to the requirement of RCC compaction. Moreover, the real-time criteria for site quality control were determined based on the similarity rate. For the compaction quality control of combination between RCC layers, the index of unit area compaction power(UAP) reached the layer surface was proposed. The quantitative correlation between the UAP and the compaction quality was analyzed to obtain its control criteria in construction.(3) Using the vibrating compaction molding machine to mold RCC specimens, the correlations of vibrating time and compaction density were analyzed under the circumstances with different VC values. Besides, the relationship of VC and compressive strength was also studied. According to the analysis, the effect rules of VC on the unit compaction power was obtained, and then the control criteria for the unit compaction power index with different VCs were proposed. The shear strength test was taken to analyze the correlation of interval time between layers and shear strength for RCC layer surface. Meanwhile, the initial setting time of RCC was discussed. Thus the control criteria for interval time between layers was obtained accordingly. |
