Influence mechanism and calculation model of CPB rheological parameters
-
摘要: 首先對膏體物料特性開展量化表征研究，通過分析膏體細觀結構的物質組成，提出了一種全面描述物料特征的綜合指標——固體填充率；開展膏體流變實驗，基于賓漢模型對流變曲線進行擬合獲得相應的屈服應力及塑性黏度，分析了體積分數、質量加權平均粒徑、不均勻系數、細顆粒及水泥質量分數等因素對流變參數的影響規律，并從細觀結構的角度對其影響機制進行了解釋，最終構建了流變參數關于固體填充率的計算模型.研究結果表明：相同條件下，膏體屈服應力及塑性黏度隨體積分數增大呈指數增大，隨物料不均勻系數增大而減小，隨細顆粒含量增大呈先減小再增大的變化趨勢.Abstract: First, the quantitative characterization of cement paste backfilling (CPB) material characteristics was studied, and a comprehensive index called solid filling rate was presented to describe the interaction of material characteristics, through analyzing the substance composition of CPB microstructure. Then, rheological experiments were made to get the corresponding rheological curves, which were fitted by the Bingham model to get the yield stress and plastic viscosity of CPB. The influence of material characteristics such as volume fraction, weighted average grain diameter, nonuniform coefficient, the mass fraction of fine particles and cement on CPB rheological parameters was analyzed, and its mechanism was explained from the view of microstructure. At last, a calculation model of rheological parameters including solid filling rate was constructed. The results indicate that under the same conditions, the yield stress and plastic viscosity increase exponentially along with the increase of volume fraction, decrease with the increase of nonuniform coefficient, and decrease first and increase soon with the increase of fine particles.
-
Key words:
- paste backfilling /
- yield stress /
- plastic viscosity /
- particle size distribution /
- flocculent structure
-
參考文獻
[1] Nehdi M, Rahman M A. Estimating rheological properties of cement pastes using various rheological models for different test geometry, gap and surface friction. Cem Concr Res, 2004, 34(11):1993 [6] Cheng D C H, Kruszewski A P, Senior J R, et al. The effect of particle size distribution on the rheology of an industrial suspension. J Mater Sci, 1990, 25(1):353 [7] He M Z, Wang Y M, Forssberg E. Slurry rheology in wet ultrafine grinding of industrial minerals:a review. Powder Technol, 2004, 147(1):94 [8] Kranenburg C. The fractal structure of cohesive sediment aggregates. Estuar Coast Shelf Sci, 1994, 39(6):451 [11] Wallevik J E. Rheological properties of cement paste:thixotropic behavior and structural breakdown. Cem Concr Res, 2009, 39(1):14 [13] Zhou J Z Q, Uhlherr P H T, Luo F T. Yield stress and maximum packing fraction of concentrated suspensions. Rheol Acta, 1995, 34(6):544 [15] Liddel P V, Boger D V. Yield stress measurements with the vane. J Non-Newtonian Fluid Mech, 1996, 63(2):235 [16] Saak A W, Jennings H M, Shah S P. The influence of wall slip on yield stress and viscoelastic measurements of cement paste. Cem Concr Res, 2001, 31(2):205 -
點擊查看大圖
計量
- 文章訪問數: 834
- HTML全文瀏覽量: 251
- PDF下載量: 20
- 被引次數: 0
下載:
