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

第二个研究周期的建议是基于题为“添加剂对水泥系统中粉煤灰溶解机制的影响”的研究项目的第一部分。调查结果导致了新的问题，这些问题需要用适当的方法加以澄清。特别是，所用有机添加剂在粉煤灰玻璃溶解过程中的催化作用的假设需要验证。粉煤灰表层硫酸盐对添加剂作用的影响也需要进一步研究。此外，还考虑了添加剂的分散作用，研究结果将有助于确定导致用有机添加剂制备的粉煤灰砂浆性能更好的单独效应。此外，低碱波特兰水泥也包括在研究中，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（如增塑剂）的普遍使用，必须研究有机添加剂与混凝土外加剂的相互作用，以便进行广泛的评估。

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.