The paper presents results of tests on the effect of the addition of siliceous fly ashes (FA) in the amount of: 0, 20 and 30% by weight of cement on the interfacial microcracks and mechanical parameters in plain concrete. The environmental and utilitarian aspects of the analyzed problem were taken into account in the studies.

The analyses were carried out based on the results of the macroscopic and microstructural tests.

During macroscopic investigations fracture toughness (K_IIc) and compressive strength (f_cm) of concretes were assessed, whereas based on microscopic examinations, the average width of the microcracks (W_c) in the Interfacial Transition Zone (ITZ) of coarse aggregate with cement matrix was evaluated.

In the own testing, it was demonstrated that there is a direct relationship between the observed W_c and designated f_cm and K_IIc. Based on these results, it was found that with the decrease of the W_c, the mechanical parameters increases. Using the 20% FA cement binder causes favorable changes in the microstructure and affects the improvement of mechanical parameters of mature concrete. Moreover, such treatments also causes a lot of benefits – both from the point of view of ecology and sustainable construction.

本文介绍了添加0、20和30％水泥（重量）的硅粉煤灰（FA）对普通混凝土中界面微裂纹和力学参数的影响的测试结果。在研究中考虑了所分析问题的环境和功利方面。

分析是根据宏观和微观结构测试的结果进行的。

在宏观研究中，评估了混凝土的断裂韧性（K _IIc）和抗压强度（f _cm），而在微观检查的基础上，水泥粗骨料的界面过渡区（ITZ）中的微裂纹的平均宽度（W _c）得到了评估。评估矩阵。

在自己的测试中，已证明观察到的W _c与指定的f _cm和K _IIc之间存在直接关系。基于这些结果，发现随着W _c的降低，机械参数增加。使用20％FA水泥粘合剂会导致微观结构发生有利变化，并影响成熟混凝土的力学参数的提高。此外，从生态学和可持续建设的角度来看，这种处理也带来了很多好处。