CFB飞灰压浆料的制备及高强微膨胀机理研究

Preparation and High-Strength Micro-Expansion Mechanism of CFB Fly Ash Compaction Slurry

利用循环流化床燃煤固硫灰(CFB飞灰)的活性与膨胀性制备压浆料,研究了CFB飞灰掺量和水胶比对压浆料工作性能、强度和膨胀率的影响;CFB飞灰与矿粉以不同比例复配,对比研究了CFB飞灰压浆料的高强微膨胀特性,并采用XRD与SEM分析验证。结果表明,随CFB飞灰替代水泥掺量的增加,压浆料的需水性增强,抗压强度降低,20%(质量分数)CFB飞灰的试样28 d抗压强度与基样接近,可达85.8 MPa,而抗折强度先升高后降低,膨胀率一直升高。随用水量的增加,压浆料的膨胀率降低但均为正值。随CFB飞灰取代矿粉率的提高,压浆料的工作性能降低,28 d抗压强度先升高后降低,其中20%(质量分数)CFB飞灰、10%(质量分数)矿粉复合的试样28 d抗压强度最高,为99.8 MPa,膨胀率一直升高。通过CFB飞灰与矿粉复合配制了各项性能均满足铁标要求的压浆料。CFB飞灰不仅自身水化产生膨胀,还能激活矿粉活性,产生复合增强作用。

The activity and expansibility of circulating fluidized bed coal-fired sulfur-fixed ash(CFB fly ash)were utilized to prepare compaction slurry.The effects of CFB fly ash content and water-binder ratio on the workability,strength and expansion rate of the compaction slurry were investigated.CFB fly ash and mineral powder were mixed in different ratios,and the high-strength and micro-expansion characteristics of CFB fly ash compaction slurry were studied and verified by XRD and SEM analyses.The results show that,with the increase of CFB fly ash replacing cement content,the water demand of the compaction slurry increases and the compressive strength decreases.The 28 d compressive strength of the specimen with 20%(mass fraction)CFB fly ash is close to that of the base sample,up to 85.8 MPa,while the flexural strength rises first and then decreases,and the expansion rate rises sequentially.With the increase of water consumption,the expansion rate decreases but is positive.With the increase of the rate of CFB fly ash replacing mineral powder,the workability decreases,and the 28 d compressive strength rises first and then decreases.The specimen with 20%(mass fraction)CFB fly ash and 10%(mass fraction)mineral powder has the highest 28 d compressive strength,which is 99.8 MPa,and the expansion rate has been increasing.The various properties of compression slurry with CFB fly ash and mineral powder meet the requirements of the iron standard.CFB fly ash not only expands by its own hydration,but also can activate the activity of mineral powder,resulting in a composite enhancement effect.