粉煤灰品质对碾压混凝土性能的影响

为解决某工程大坝碾压混凝土Ⅰ级粉煤灰供应不足的问题，探讨了用Ⅱ级粉煤灰替代Ⅰ级粉煤灰的可能性。对数家Ⅰ级粉煤灰和Ⅱ级粉煤灰的物理化学品质进行了试验，同时通过混凝土性能试验论证其使用效果，确定合适掺量和其它配合比参数。试验比较了粉煤灰品质对碾压混凝土抗压强度、抗拉强度、极限拉伸值、抗冻融性能、绝热温升、抗渗等对其性能的影响，讨论了粉煤灰品质指标影响混凝土各项性能的机理。在此基础上提出了大坝混凝土合理使用粉煤灰的原则。

The Influence of Fly Ash Quality on RCC Performance

In order to address the shortage of Grade-Ⅰ fly ash for roller compacted concrete (RCC) dam, the possibility of replacing Grade-Ⅰ fly ash with Grade-Ⅱ fly ash was explored. The physical and chemical properties of Grade-Ⅰ and Grade-Ⅱ  fly ashes provided by several power plants were tested. Their performances were demonstrated and the proper dosage and other mix ratios were determined. The influences of various fly ashes on the compressive strength, tensile strength, ultimate tensile values, anti-freeze-thaw performance, the adiabatic temperature rise, impermeability and other properties of RCC were analyzed and compared. The mechanism of fly ash affecting the concrete properties were discussed. The principle of the rational use of fly ash for dam concrete was put forward.