Mutual activation of blast furnace slag and a high-calcium fly ash rich in free lime and sulfates

Sahin, Murat
Mahyar, Mahdi
Erdoğan, Sinan Turhan
Alkaline activation of fly ash and blast furnace slag has gained interest due to a desire to avoid Portland cement in mixtures. Outstanding mechanical performance and durability is reported, but often when the activator dosage is high which can have various negative environmental impacts that can overshadow the carbon reduction benefit. This study investigates the use of a ground slag, and a high-lime fly ash, rich in free lime and sulfates, to activate each other and render mortars which don't incorporate any Portland cement or an added chemical activator, but still have useful strengths. The ash, which does not conform to standards for use in concrete, hence is nearly completely landfilled, is used as-received or after grinding. 28-day compressive strengths surpassing 13 MPa and 20 MPa were recorded, for samples cured at 23 degrees C or at 80 degrees C. Various combinations of the two powders have heats of hydration lower than that of a typical Portland cement. Ettringite and CSH are determined to be responsible for the early and ultimate strength gain. The effect of adding gypsum to the system as a low-impact activator is also investigated.


Use of granulated blast furnace slag and lime in cement-bentonite slurry wall construction
Talefirouz, D.; Çokça, Erdal; Omer, J. (2016-01-01)
This paper describes an experimental investigation on the use of ground granulated blast furnace slag (GGBFS) and lime as stabilizers for cement-bentonite (CB) slurry used in constructing vertical barrier walls. The primary objective is to develop a blended material, which can reduce the permeability and also enhance the strength of CB slurry walls with a shortened curing time. Mixtures comprising various proportions of cement, bentonite, GGBFS, and lime were prepared and tested for particle size distributi...
Sulfate resistance of cementitious systems with mineral additives
Dilek, Faruk Tuncer; Tokyay, Mustafa; Department of Civil Engineering (2002)
Sulfate resistance of mortars containing limestone, trass, granulated blast furnace slag and fly ash has been evaluated using ASTM C 1012 test procedure. Prismatic and cubic mortar specimens have been stored in concentrated sodium sulfate and a mixture of sodium sulfate + magnesium sulfate solutions. Relative deterioration of the specimens has been determined by length change, weight change, strength and visual examination. From similar mixtures, cement paste specimens were prepared and structure/morphology...
Comparison of intergrinding and separate grinding for the production of natural pozzolan and GBFS-incorporated blended cements
Erdogdu, K; Tokyay, Mustafa; Turker, P (1999-05-01)
A portland cement clinker, a natural pozzolan, and a granulated blast furnace slag (GBFS) were used to obtain blended cements that contain 25% mineral additives. The natural pozzolan, which was softer, was more grindable and granulated blast furnace slag, which was harder, was less grindable than the clinker. Two of the cements produced were obtained by intergrinding and the other two were obtained by separate grinding and then blending. All of the blended cements and the control cement without any additive...
Graphene oxide/magnesium oxide nanocomposite: A novel catalyst for ozonation of phenol from wastewater
Heidarizad, Mahdi; Şengör, Sema Sevinç (2017-01-01)
Catalytic ozonation is a promising advanced oxidation technique for the removal of contaminants from water and wastewater. Graphene oxide (GO) is an oxidized derivative of graphene which contains epoxide, hydroxyl, and carboxyl groups with high surface area, and is being recently used for effective adsorption of pollutants in aquatic environments. In our previous work, we modified GO with magnesium oxide (MgO) and demonstrated the high-rate adsorption of methylene blue (MB) by the synthesized nanocomposite ...
Compressive strength development of calcium aluminate cement-GGBFS blends
Kirca, Onder; Yaman, İsmail Özgür; Tokyay, Mustafa (2013-01-01)
The compressive strength development of calcium aluminate cement (CAC) and ground granulated blast furnace slag (GGBFS) blends that were subjected to different curing regimes are investigated. The blends had GGBFS/CAC ratios between 0% and 80%, by mass. Mortar specimens, prepared with a water:binder:sand ratio of 1:2:6, were subjected to seven different curing regimes and the compressive strengths were monitored up to 210 days. In order to understand the effect of temperature on compressive strength develop...
Citation Formats
M. Sahin, M. Mahyar, and S. T. Erdoğan, “Mutual activation of blast furnace slag and a high-calcium fly ash rich in free lime and sulfates,” CONSTRUCTION AND BUILDING MATERIALS, pp. 466–475, 2016, Accessed: 00, 2020. [Online]. Available: