The chemical reagents influence on the regulation of the powder composite materials setting time for construction purposes

Additives were selected, and a method for modifying the structure of gypsum-containing materials for construction purposes and a method for their dispersion were developed. Based on the selected modifiers, effective compositions of composite gypsum-containing materials based on local and secondary raw materials were developed. An increase in their strength and resistance to water was established. The use of gypsum plaster mixes shows their high efficiency and advantages compared to traditional finishing works methods. They provide a high and stable level of finishing quality, reduced transportation costs, and easy recycling of materials. However, despite the high consumer properties, the modern use of compositions based on the most affordable gypsum raw materials in the Republic and the production of gypsum binder beta calcium sulfate semi hydrate is limited to plasters and putties for rooms with normal operation. This is mainly because the compositions have a short setting time, low water resistance, and low strength characteristics. As a rule, the softening factor for such compositions does not exceed 0.5, and the compressive strength is 4-6 MPa

Quick Setting Composition Based on Steelmaking Metallurgical Slag

The article deals with the problem of utilizing steelmaking slag from the production of rapid hardening composition in Izhstal, CJSC (Izhevsk, Russia), determining its physical and mechanical characteristics, and applying its properties for renovation and reconstruction. The physical and mechanical characteristics of the developed mortar exceed the existing analogues in many parameters (setting speed, strength). Dry mortar has a short setting time (the end of setting occurs 3,5 minutes after mixing with water at W/S = 0,3), its strength being 66,8 MPa after 28 days of normal hardening. The results show this mortar can be used for emergency renovation work to stop leaks in concrete, stone and brick structures. The studies were conducted using the methods of physical and chemical study of the structure and properties of the produced composition. The developed composition helps reduce the environmental pressure in places of electric steelmaking slag dump.

Tuning of PID Controller for the Integrating Systems

According to the idea of the system identification, 2-DOF PID based on the desired dynamic equation (DDE-PID) has been improved. The DDE-based PID is applied to the integrating system. This method only needs the step response information of the plant, which is easy to be obtained. According to the physical meaning of parameters, the tuning is also convenient to meet the requirement of the dynamic performance. The simulations show that the method has the low overshoot and the short setting time on the integrating system.

Assessment of Heat Resistant Concrete of Magnesia-Phosphate

In this paper, we choose heat resistant material wollastonite and corundum to get the concrete which has heat resistance up to 600 centigrade. SEM reveals that at the temperature of 400 centigrade and 600 centigrade, the material is very dense. But when the temperature gets 800 centigrade and 1000 centigrade, the SEM reveals cracks. The refractory concrete made by magnesium potassium phosphate as the binder and wollastonite and corundum as aggregate has short setting time, early strength and rapid hardening. And it is suitable for emergency repair materials for the kiln.

The Role of Fly Ash in the Granulated Blast Furnace Slag-Based Geopolymer

Inorganic polymers using slag as cementitious materials have the advantage of a short setting time, high early strength, but the sensitivity of the reaction rate to temperature and the likelihood to subsequently crack, which leads to reduction of strength, limit its application. This article, by configuring different proportion of fly ash and slag, studied its dry shrinkage with the different kinds of activator, the effects of fly ash on the hydration heat release curves, differences of setting time and strength with different configuration, and then explored the effect of fly-ash in inorganic polymer. Experiments had shown that through rational configuration, the addition of fly ash can effectively reduce the rate of heat release and the amount of heat, meanwhile can solve the problem about short setting time of alkali-activated cementitious materials without reducing its strength.

Fuzzy PID Temperature Control in Manufacturing Engineering

This paper introduces the basic concept of fuzzy PID in manufacturing engineering, and the system of temperature control is analyzed, and the temperature is designed with correction factor and the optimized parameters with the application of the fuzzy general MATLAB in simulink toolbox, the temperature is designed by comparing fuzzy PID output with raditional output, the system has the characteristic of quick response, short setting time, small overshoots, and high control precision.