The article presents the third stage of the study results of a complex modified additive (CMA), in the accuracy of the influence of the variable ingredients of CMA on the strength of cement. This article shows the methodology of making samples, the selection of additive composition at different percentages of components, and the analysis of the strength behavior of the obtained results. To evaluate the changes in strength, samples were made and tested in compression and bending at 7, 14, and 28 days of normal-moist hardening. The results of the experiment showed that the addition of plasticizers (PAB) reduces the quantity of water - 35%, by increasing the strength of concrete by 20%. Compressive and bending strength results of the modified samples showed the best results, which were in the range of 42.80-63.66 MPa and 3.34-8.75 MPa, compared with the control composition. From the results of the research, the additive accelerates hardening and it was found that the additive contributes to the growth of strength, both at an early age and at the design age (28 days). The results of the experiment showed that from the standpoint of improving the qualitative characteristics of the samples, the use of plasticizers is appropriate. The use of CMA in the composition of concrete increases the strength, and therefore developed by the authors of CMA changes the structure of concrete and most importantly, increases the physical and mechanical characteristics of concrete.

The article presents studies of the effect of a complex modified additive on the setting time of cement paste. The work describes the method of determining the setting time of the cement paste of standard consistency, the selection of the optimal composition of the additive at different percentages of its components, allowing accelerating the setting time. In this work, the authors used a complex modified additive including alkali (caustic soda NaOH), post-alcohol bard (alcohol production waste), and hardening accelerator (gypsum) in different percentages. Performed a comparative study of the effect of additives on changes in setting time. The analysis suggests that the additive in the optimal amount leads to changes in the setting time compared with the reference sample, but within the standards. It is shown that the combined use in the composition of a complex modified additive, having well-compatible mechanisms of their influence on the processes of hydration, setting, and hardening of the cement paste, mutually complements and enhances the effect of each ingredient of the additive. Increasing the concentration of the complex modified additive in the cement paste not only affects the liquefaction process but also reduces the setting time and hardening of the cement paste.