Ślusarek Jan, Nowoświat Artur, Olechowska Marcelina
Faculty of Civil Engineering, Silesian University of Technology, Akademicka 2A, 44-100 Gliwice, Poland.
Materials (Basel). 2022 Jun 22;15(13):4403. doi: 10.3390/ma15134403.
The objective of this study was to analyze the effects of the modification of cementitious materials with the admixture of a superplasticizer and mineral additive in the form of microsilica. We analyzed the hardening process of cementitious materials as an autocatalytic transformation from a viscous liquid to a pseudo-solid body. The main achievement of the research involved the identification of changes in the content of the solid phase during the hardening of concrete mix as a model of the logistic curve. The phase transformation process begins with a viscous liquid which consists of water, cement, microsilica, superplasticizer and sand. The laboratory tests comprised research on the development of the kinetics of hardening heat of binder cement pastes and the development of mechanical properties of concrete in the hardening process. Three groups of mixtures with different concentrations of binders, determined by different water-binder indexes, were used. The first group was made up by cement paste consisting of cement and water. The second group contained cement paste from the first group supplemented with a superplasticizer, and the third group comprised the cement paste as in the second group, but additionally modified with microsilica. Using appropriate analyses, we defined a mathematical model of the phase transformation process. The model was then used for computer-aided numerical analyses. This made it possible to compare the relevant parameters of the logistic curve obtained for the seven different concrete mixes analyzed. Active impact of the applied mineral additive (microsilica) and that of chemical admixture in the form of a superplasticizer was demonstrated. All approximations of the measurement results with the use of a logistic curve had a determination level of over 0.98, indicating high agreement.
本研究的目的是分析用高效减水剂和微硅粉形式的矿物添加剂对胶凝材料进行改性的效果。我们将胶凝材料的硬化过程分析为从粘性液体到准固体的自催化转变。该研究的主要成果包括确定混凝土拌合物硬化过程中作为逻辑曲线模型的固相含量变化。相变过程始于一种粘性液体，它由水、水泥、微硅粉、高效减水剂和沙子组成。实验室测试包括对胶凝水泥浆体硬化热动力学发展以及混凝土在硬化过程中力学性能发展的研究。使用了三组由不同水胶比确定的不同浓度胶凝材料的混合物。第一组由水泥和水组成的水泥浆体构成。第二组包含第一组的水泥浆体并添加了高效减水剂，第三组包含与第二组相同的水泥浆体，但额外用微硅粉进行了改性。通过适当的分析，我们定义了相变过程的数学模型。然后将该模型用于计算机辅助数值分析。这使得能够比较所分析的七种不同混凝土拌合物获得的逻辑曲线的相关参数。结果表明了所应用的矿物添加剂（微硅粉）和高效减水剂形式的化学外加剂的积极影响。使用逻辑曲线对测量结果进行的所有近似，其决定系数均超过0.98，表明吻合度很高。
