fly ash

Physico-Chemical Peculiarities of Weighted Thermostable Plugging Materials Hydration

A new competitive class of plugging compositions (weighted non-shrink plugging materials) has been created using as components a fly ash from thermal power station, a weighting additive and a superplasticizer. X-ray phase analysis identified the composition of new materials formed in the hydration process of the developed plugging compositions. The kinetic curves of the plugging material expansion in a wide temperature range have been obtained.

DESIGNING OF ALKALINE ACTIVATED CEMENTING MATRIX OF ENGINEERED CEMENTITIOUS COMPOSITES

The development of high-performance materials, which are characterized by high compressive and flexural strength, durability and performance properties, is an urgent problem of modern construction. Engineered cementitious composites are one such material. Improving of properties of composites is achieved by partial replacement of cement with supplementary cementitious materials. The ratio of binder and filler components and superplasticizer consumption were selected.

MODIFICATION OF CEMENTITIOUS MATRIX OF RAPID-HARDENING HIGH-PERFORMANCE CONCRETES

The paper presents the results of research concerning the peculiarities of modern High Performance Concretes based on cementitious systems "Portland cement – active mineral additives – micro fillers – superplasticizers – accelerators of hardening". Physico-chemical regularities of structure formation of super plasticized cementitious systems are established.

Development of Heterogeneous Alkali Methoxide Catalyst from Fly Ash and Limestone

This study is aimed to use fly ash and limestone as raw materials for preparing alkali methoxide heterogeneous catalysts for transesterification of palm oil into biodiesel. The heterogeneous catalyst was synthesized from fly ash and limestone through wet and dry methods and calcined within 1073–1273 K. X-ray diffraction and scanning electron microscopy analyses indicated the well-dispersed presence of the Ca(OCH3)2 crystal over the fly ash and limestone framework, which was mixed using wet method and calcined at 1073 K (W-800).

SELF-СOMPACTING СONCRETES, HARDENING AT DIFFERENT TEMPERATURE CONDITIONS

In the article the features of reinforced concrete hardening at different temperature conditions and the current issues of preparation technology of Self-Сompacting Сoncretes (SCC) on the basis of superplasticized cementitious systems, combining knowledge of structure and modifying Portland cement compositions "Portland cement – active mineral additives – microfiller – superplasticizer – accelerator of hardening" to search for rational making provision of technical and building properties of concrete in the changing factors of its composition, technology and exploitation are shown.

X-ray fluorescence method and thermal analysis of concrete prepared based on a share of fly ash and various chemical admixtures

The utilization of fly ash in concrete as partial cement replacement has many benefits. It leads to increase of a binder´s amount and improves workability (pumpability, keepability and others) of fresh concrete, as fly ash behaves as a solid fluidifier. Application of fly ash in combination with a fluidifier is very effective, because it improves the workability of fresh concrete significantly. Regarding characteristics of lower class fresh concrete the main benefit of fly ash utilization with fluidifier is complement of fine binder, especially particles up to 0,25mm.

Фіброармовані самоущільнювальні бетони з високим вмістом золи винесення

The possibility of obtaining Self-Compacting Concrete with a large amount of supplementary cementitious materials, including fly ash is shown in this article. Research results of rheological properties of fiber reinforced Self-Compacting Concretes with high volume of fly ash and chemical admixtures, which regulate fluidity and viscosity of concrete mixes, are shown. It was established that the replacement of 55, 70 and 85 wt. % of binder with fly ash allows to obtain Self-Compacting Concrete mixes with the consistency class SF2, viscosity T500 = 5 s and the volume of entrained air 0,4 %.

Low Energy Consuming Modified Composite Cements and their Properties

 It has been shown that in the conditions of aggravation of ecological problems, shortage of high-quality raw materials for the production of Portland cement clinker a promising direction of cement industry development is more extensive waste utilization as well as production of low energy consuming cement clinker and modified composite cements, characterized by high content of active mineral additives.

Pozzolanic Activity Diagnostics of Fly Ash for Portland Cement

The work deals with the analysis and evaluation of different methods of pozzolanic activity determination in order to rationally use ash in cement. The most optimum diagnostic method has been suggested. The possibility of increasing fluidal fly ash activity has been established using the synthetic nanosilica.