Effect of additives on dissolution mechanisms of fly ash in cementitious systems

第二个研究阶段的提案是基于题为“添加剂对粉煤灰在胶凝体系中的溶解机制的影响”的研究项目的第一部分。调查结果带来了新的问题，需要用适当的方法加以澄清。特别是，所使用的有机添加剂在粉煤灰玻璃溶解过程中的催化作用假说需要得到验证。此外，粉煤灰表层提供的硫酸盐对添加剂作用的影响还有待进一步研究。此外，要考虑添加剂的分散作用。研究结果将有助于确定有机添加剂对粉煤灰砂浆性能的影响。此外，低碱硅酸盐水泥也被纳入研究范围，因为碱对粉煤灰和有机添加剂都有很大的影响。由于混凝土外加剂的普遍使用，例如增塑剂，有机添加剂与混凝土外加剂的相互作用必须进行广泛的评估研究。

This proposal for a second research period is based on the first part of the research project entitled Effect of Additives on Solubility Mechanisms of Fly Ash in Cementitious Systems. The results of the investigations led to new issues which are to be clarified with suitable methods. In particular, the hy-pothesis of the catalytic action of the used organic additives during the dissolution of fly ash glass needs to be verified. Also the effect of sulphates supplied by the surface layers of fly ash on the action of the additives needs further investigation. Additionally, a dispersing action of the additives is to be considered.The research results will enable determination of the individual effects which lead to better perfor-mance of fly ash mortar made with organic additives.Furthermore, low alkali Portland cement is included in the investigations because alkalis considerably affect both fly ash and organic additives. Due to the common use of concrete admixtures, e.g. plasti-cizers, the interaction of the organic additives with concrete admixtures has to be investigated for a broadly based assessment.