【作者】 董刚；

【导师】 陈益民；

【作者基本信息】 中国建筑材料科学研究总院 ， 材料学， 2008， 博士

【摘要】 粉煤灰和矿渣现已成为高性能水泥中必不可少的性能调节型辅助性胶凝材料,确定水泥浆体中粉煤灰或矿渣的反应程度,对评价它们的反应活性及其对该体系结构形成的贡献、研究反应动力学等具有重要意义。由于粉煤灰质量的变异性很大,因地制宜地选取代表性粉煤灰,找出粉煤灰的组成、颗粒级配与反应程度之间的关系就显得非常有必要。本文选取全国有代表性的粉煤灰与矿渣,采用选择性溶解法测定了粉煤灰和矿渣的反应程度,研究了水泥浆体中粉煤灰或矿渣的反应程度与比表面积、掺量、龄期等参数的关系,并建立了关联模型;分析了粉煤灰或矿渣的反应程度、反应深度以及粒径分布参数之间相关关系;探索了粉煤灰与矿渣反应消耗的氢氧化钙的量与粉煤灰或矿渣的反应程度之间的关系以及水泥胶砂强度与反应程度之间的关系;以单位粉磨能耗对反应程度以及水泥胶砂强度的贡献为参数,对粉煤灰和矿渣作为辅助胶凝材料应用进行了能量经济分析。研究结果表明,粉煤灰、矿渣的反应程度与比表面积、掺量以及水化龄期之间近似符合幂函数关系。不同种类粉煤灰的反应程度大小顺序为:中钙型>高钙型>低钙高铝型>低钙中铝型(7d、28d);低钙高铝型>中钙型>高钙型>低钙中铝型(90d)。从反应程度方面来说,粉煤灰的推荐比表面积为:以石景山粉煤灰为代表的低钙高铝型粉煤灰,600±10m2/kg;以宝钢粉煤灰为代表的中钙粉煤灰,600±10m2/kg(90d及以前),500±10m2/kg(180d);以石横粉煤灰为代表的低钙中铝型粉煤灰,700±10 m2/kg(28d及以前),500±10 m2/kg(90d)。矿渣的推荐比表面积为500±10m2/kg。当粉煤灰或矿渣掺量为50%,水胶比为0.5时,粉煤灰以及矿渣在各龄期的反应程度与粒径特征参数呈负相关。在各个粒径特征参数中,表面积平均粒径与粉煤灰或矿渣的反应程度之间联系最紧密。粉煤灰在90d龄期时的反应程度以及矿渣的反应程度均与表面积平均粒径呈线性相关。水泥胶砂抗压强度与粉煤灰或矿渣的反应程度之间呈现出良好的对数关系。因此,表面积平均粒径可作为粉煤灰、矿渣粉体加工的质量控制参数。表面积平均粒径同时兼顾了颗粒分布和比表面积的特点,它比单纯采用勃氏比表面积或筛余作为控制指标要更科学,更能反映粉煤灰和矿渣粉体的微观特性。根据粉煤灰和矿渣的粒径分布参数,可以由粉煤灰或矿渣的反应程度推导出其反应深度。粉煤灰的反应深度大小顺序为:高钙型>中钙型>低钙中铝型>低钙高铝型(7d);中钙型>高钙型>低钙高铝型>低钙中铝型(28d、90d)。随着粉磨时间的增加,粉煤灰的比表面积呈线性增长,矿渣的比表面积呈对数增长。随着粉煤灰或矿渣比表面积的增加,其颗粒均匀性系数亦增加,特征粒径降低;但当比表面积增加到600m2/kg左右时,随着比表面积的提高,颗粒均匀性系数开始下降或基本上不再改变。当粉煤灰掺量为50%、水胶比为0.5时,水泥浆体中氢氧化钙消耗量与粉煤灰的反应程度之间近似服从线性相关。当矿渣掺量为50%、水胶比为0.5时,水泥浆体中氢氧化钙消耗量与矿渣的反应程度的相关性不显著。从单位粉磨电耗对粉煤灰或矿渣的反应程度的增加量的贡献来看,粉煤灰与矿渣的推荐比表面积为:低钙高铝型粉煤灰,600±10m2/kg(1d、3d),700±10m2/kg(7d、14d、28d、60d、90d、180d);中钙型粉煤灰,600±10m2/kg(1d、3d、7d、14d、28d、60d、90d),500±10m2/kg(180d);低钙中铝型粉煤灰,600±10m2/kg(3d), 700±10m2/kg(7d、28d);500±10m2/kg(90d);矿渣:500±10m2/kg。更多还原

【Abstract】 Fly ash and blast furnace slag have become absolutely necessarily binding materials in cement industry. To make sure the reaction degree of fly ash and blast furnace slag in cement pastes is very important. It is significant in evaluating the reactive activity of fly ash and blast furnace slag ,estimating the contribution to the structure, researching the reactive kinetics. The quality of fly ash varies in a big range. It is vital to select typical fly ash and research the relationship among the reaction degree, constitute and particle size distribution of fly ash.In this dissertation, typical fly ash and slag were selected and the reaction degree of fly ash and blast furnace slag were measured by selective solution method at first. Then, the relationship between reaction degree of fly ash or blast furnace slag in cement pastes and specific surface area of fly ash or blast furnace slag, replacement ratio of fly ash or blast furnace slag at different ages were constructed. Correlation among reaction degree, reaction depth and particle size distribution parameter were established. The relationship between Ca(OH)2 reduction content in cement pastes and reaction degree of fly ash and blast furnace slag and the relationship between strength and reaction degree of fly ash and blast furnace slag were also researched. Lastly, the contribution of every grinding energy cost to reaction degree and strength were analyzed.The results showed that the reaction degree of fly ash or blast furnace slag has good power function correlation with specific surface area of fly ash or blast furnace slag, replacement ratio of fly ash or blast furnace slag and ages. The sequence of reaction degree of different fly ashes were: median calcium type>high calcium type>low calcium with high aluminum type>low calcium with median aluminum type (7d,28d);and low calcium with high aluminum> median calcium type> high calcium type>low calcium with median aluminum type(90d). The proposed specific surface area of fly ash and slag for good reaction degree were: 600±10m2/kg for low calcium high aluminum type fly ash; median calcium type,600±10m2/kg(90d or before it), 500±10m2/kg(180d);low calcium median calcium type, 700±10 m2/kg(28d or before it),500±10 m2/kg(90d);slag, 500±10m2/kg.When the replacement ratio of fly ash or blast furnace slag is 50% and the ratio of water to binding materials is 0.5, reaction degree of fly ash or blast furnace slag has negative correlation with particle size distribution characteristic parameter. Of all the characteristic parameter, the correlation between reaction degree and surface area mean particle size is best. Reaction degree of fly ash or blast furnace slag has good liner correlation with surface area mean particle size. Compressive strength of cement pastes has good logarithmic correlation with reaction degree of fly ash or blast furnace slag. So, surface area mean particle size can be good quality control parameter for fly ash or blast furnace slag. Surface area mean particle size has the trait of both particle size distribution and special surface area,it is more scientific than sieve residue or specific surface area as quality control parameter for fly ash or blast furnace slag.Based on the particle size distribution parameter of fly ash or blast furnace slag, reaction depth of it can be deduced from reaction degree of it. The sequence of reaction depth of different fly ashes were: high calcium type> median calcium type>low calcium with median aluminum type >low calcium with high aluminum type (7d), and median calcium type> high calcium type>low calcium with high aluminum> low calcium with median aluminum type(28d,90d).The increase of specific surface area of fly ash has positive liner correlation with the increase of grinding time. The increase of specific surface area of blast furnace slag has positive logarithmic correlation with the increase of grinding time. With the increase of specific surface area for fly ash or blast furnace slag, the particle equality coefficient increase and characteristic particle size decrease. When the specific surface area add to 600m2/kg,the equality coefficient begin to drop or stabilize.When the replacement ratio of fly ash or blast furnace slag is 50% and the ratio of water to binding materials is 0.5, Ca(OH)2 reduction content in cement pastes have good liner correlation with reaction degree of fly ash, Ca(OH)2 reduction content in cement pastes have no good relation with reaction degree of blast furnace slag.From the contribution of grinding energy to reaction degree of fly ash or blast furnace slag, the proposed specific surface area of fly ash and blast furnace slag were: low calcium high aluminum type fly ash , 600±10m2/kg(1d,3d), 700±10m2/kg (7d,14d,28d, 60d,90d,180d) ; median calcium type,600±10m2/kg(90d or before it), 500±10m2/kg(180d);low calcium median aluminum type, 600±10 m2/kg(3d), 700±10 m2/kg(7d,28d),500±10 m2/kg(90d);blast furnace slag, 500±10m2/kg.更多还原