The Effects of Silica Fume and Superplasticizer Type on the Properties and Microstructure of Reactive Powder Concrete.

This paper deals with the optimization of reactive powder concrete mixtures with respect to the addition of silica fume and the type of polycarboxylate superplasticizer used. First, the properties of reactive powder concrete with eight different commercial polycarboxylate superplasticizers were tested in terms of workability, specific weight, and mechanical properties. It was found that different commercially available superplasticizers had significant effects on the slump flow, specific weight, and compressive and flexural strengths.

Influence of Fumed Nanosilica on Ballistic Performance of UHPCs.

This research delves into the potential use of fumed nanosilica in ultra-high performance concrete for ballistic protection. First, the mechanical properties, slump flow, and specific gravity of UHPC with different contents of Aerosil 200 were determined. Then, calorimetric studies were conducted on these cement composites.

Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties.

This study investigates the relationships between the hydration kinetics of waterglass-activated slag and the development of its physical-mechanical properties, as well as its color change. To modify the calorimetric response of alkali-activated slag, hexylene glycol was selected from various alcohols for in-depth experiments. In presence of hexylene glycol, the formation of initial reaction products was restricted to the slag surface, which drastically slowed down the further consumption of dissolved species and slag dissolution and consequently delayed the bulk hydration of the waterglass-activated slag by several days.

Influence of Anticorrosive Surface Treatment of Steel Reinforcement Fibers on the Properties of Ultra-High Performance Cement Composite.

The influence on the bond between the steel fiber and the matrix of the anticorrosive treatments of steel used for concrete reinforcement is not yet fully understood. The topic of steel fiber treatment was not also studied clearly in terms of brass removal before. This paper deals with how the brass on the surface of steel fibers behaves in the UHPC matrix and how it affects its properties.

Effect of Alkali Salts on the Hydration Process of Belite Clinker.

Belite-rich cement is a low carbon footprint binder. However, its use is accompanied by a low initial rate of hydration. This can be partially eliminated by grinding to a high specific surface or through the addition of admixtures (mineralizators or activators).

Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash.

Increasing utilization of secondary raw materials and alternative fuels results in increasing contents of metals in cements. Zinc is one of these elements. It comes to cement with secondary raw materials such as slag or fly ash or by the utilization of used tires as an alternative fuel.

Cement Kiln By-Pass Dust: An Effective Alkaline Activator for Pozzolanic Materials.

Cement kiln by-pass dust (CKD) is a fine-grained by-product of Portland clinker manufacturing. Its chemical composition is not suitable for returning back into feedstock and, therefore, it has to be discharged. Such an increasing waste production contributes to the high environmental impact of the cement industry.

Some Issues of Shrinkage-Reducing Admixtures Application in Alkali-Activated Slag Systems.

Significant drying shrinkage is one of the main limitations for the wider utilization of alkali-activated slag (AAS). Few previous works revealed that it is possible to reduce AAS drying shrinkage by the use of shrinkage-reducing admixtures (SRAs). However, these studies were mainly focused on SRA based on polypropylene glycol, while as it is shown in this paper, the behavior of SRA based on 2-methyl-2,4-pentanediol can be significantly different.

Effect of Na₃PO₄ on the Hydration Process of Alkali-Activated Blast Furnace Slag.

In recent years, the utilization of different non-traditional cements and composites has been increasing. Alkali-activated cementitious materials, especially those based on the alkali activation of blast furnace slag, have considerable potential for utilization in the building industry. However, alkali-slag cements exhibit very rapid setting times, which are too short in some circumstances, and these materials cannot be used for some applications.