基于胶浆原理的二灰碎石设计方法

为了提高二灰碎石力学强度, 假设二灰碎石为一种三级空间网状结构的分散系, 即微分散系二灰胶浆、细分散系二灰砂浆与粗分散系二灰碎石。基于抗压强度最优原则, 采用垂直振动试验方法(VVTM)确定二灰胶浆与二灰砂浆质量比, 基于密度最大原则, 采用逐级填充法确定粗集料级配, 基于抗压强度最优原则, 确定二灰碎石中二灰砂浆用量。提出了基于胶浆原理的二灰碎石组成设计方法, 并通过室内试验与现场试验对设计方法进行性能验证。验证结果表明: 当石灰与粉煤灰质量比为2:5时, 二灰胶浆力学性能和收缩性能最佳; 当细集料质量通过率的递减系数为0.65, 二灰与细集料质量比为3:2时, 二灰砂浆力学强度最大; 当粒径范围分别为19~37.5、9.5~19、4.75~9.5 mm的集料质量比为17:11:6时, 混合粗集料密度最大; 与传统方法设计的二灰碎石试件力学强度相比, 基于胶浆原理设计的试件早期(7 d)力学强度提高10%以上, 后期(180 d)力学强度提高20%以上; 不同龄期的VVTM试件与现场芯样抗压强度之比平均为0.909, 劈裂强度之比平均为0.904, 而静压成型试件与现场芯样抗压强度之比为0.457, 劈裂强度之比为0.531, 说明VVTM比静压法设计二灰碎石更科学。

Design method of LSCR based on mortar theory

In order to improve the mechanical strength of lime-fly-ash-stabilized crushed rock(LSCR), LSCR was regard as a dispersed system with 3-level spatial reticular structures, including lime-fly-ash mortar(LAM)micro dispersed system, lime-fly-ash fine aggregate mortar(LFAM)fine dispersed system, and LSCR coarse dispersed system. Based on the principle of optimal compressive strength, the mass ratio of LAM and LFAM was computed by using vertical vibration test method(VVTM). Based on the principle of optimal density, the gradation of coarse aggregate was confirmed by using step-by-step filling method. Based on the principle of optimal compressive strength, the optimal amount of LFAM in the LSCR was determined. The design method of LSCR was proposed based on mortar theory, and its performance was verified by using indoor experiment and field experiment. Verification result indicates that the mechanical properties and shrinkage properties of LAM are optimal when the mass ratio of lime to fly-ash is 2:5. When the decreasing coefficient of quality passing rate of fine aggregate is 0.65, the mass ratio of lime-fly-ash to fine aggregate is 3:2, the mechanical strength of LFAM is maximum. When the mass ratio of aggregates with particle size range of 19-37.5, 9.5-19, 4.75-9.5 mm is 17:11:6, the density of mixing coarse aggregate is maximum. Compared with the mechanical strength of LSCR specimen designed by traditional method, the early stage(7 d)mechanical strength of LSCR specimen designed by mortar theory increases by more than 10%, and the late stage(180 d)mechanical strength increases by more than 20%. The average ratio of compressive strength of VVTM specimen to specimen of site is 0.909, and the average ratio of splitting strength is 0.904. The average ratio of compressive strength of static pressure compaction specimen to specimen of site is 0.457, and the average ratio of splitting strength is 0.531. The LSCR designed by VVTM is more scientific than static pressure method.