粉煤灰粒度分布对粉煤灰-水泥胶凝体系的影响

Influence of Fly Ash Granularity Distribution on Fly Ash—Cement Binding System

该文介绍了用Malvern MS2000激光粒度仪测定几种不同细度粉煤灰的粒度分布,以灰色关联方法分析粉煤灰粒度分布与相应粉煤灰-水泥胶砂力学性能之间的相关性,并分析不同细度粉煤灰对其胶砂的强度、流动度等技术性能的影响。研究表明:粉煤灰粒度分布明显影响其胶砂力学性能;分布在0～20μm粒径范围内的颗粒对胶砂力学性能有积极贡献,其中,尤以10～20μm的颗粒贡献最大,而大于20μm的颗粒对胶砂力学性能起削弱作用;当比表面积不超过600 m2/kg时,增加粉煤灰的细度可以提高胶凝材料体系的流动性;在胶凝材料体系中掺粉煤灰时应使用高效减水剂,且随水胶比的减小,减水剂用量也要增大以满足流动性的要求;掺粉煤灰的胶砂可在减少减水剂掺量的情况下,达到与基准胶砂相同的流动度;随水胶比的降低,胶砂强度呈增高趋势。

the article introduces Malvern MS2000 Laser Granularity Analyzer used to determine the granularity distributions of several different fine fly ashes.The grey relational method is used to analyze the correlation between the fly ash granularity distribution and the relative fly ash – cement mortar mechanics performance.The study makes clear that the granularity distribution of fly ash obviously affects its mortar mechanics performance.The granularity distributed within the range of 0～20 μm is actively contributed to the mortar mechanics performance,in which the contribution of 10～20 μm granularity is the maximum,but the granularity larger than 20 μm will weaken the mortar mechanics performance.When the specific surface area does not exceed 600 m2/kg,the increment of fly ash fineness can enhance the fluidity of binding material system.The high-efficient water reducing agent should be used while the fly ash is mixed into the binding material system.The dosage of water reducing agent will be increased to satisfy the requirement of fluidity while the water-binder ratio decreases.The mortar mixed with the fly ash can reach the fluidity as same as the standard mortar under the condition to decrease the dosage of water reducing agent.The mortar strength presents the increasing trend while the water-binder ratio reduced.