Comparison of Selected Properties of Portland Cement Based Materials and Alkali Activated Materials Based on Granulated Blast Furnace Slag

2016 ◽  
Vol 865 ◽  
pp. 107-113 ◽  
Author(s):  
Pavel Mec ◽  
Jana Boháčová ◽  
Josef Koňařík

Alkali activated systems are materials formed by alkali-activation of latent hydraulic or pozzolanic materials. The outcome is a polymeric structure with properties comparable to materials based on cement.The principle of the experiment is to compare selected properties of alkali-activated materials based on blast furnace slag and using various types of activator (sodium water glass, potassium water glass, DESIL AL and sodium metasilicate) to binders based on white and Portland cements of the highest quality. The samples were left for one year in environments simulating the conditions in the interior and exterior. Selected physical-mechanical properties were evaluated and compared.

2011 ◽  
Vol 287-290 ◽  
pp. 1275-1279
Author(s):  
Yong Jia He ◽  
Lin Nu Lu ◽  
Shu Guang Hu

Compound binding material was prepared by the alkali activation of metakaolin and ground granulated blast furnace slag. Hydration product components, microstructure and mechanical properties of the hardened paste were investigated by IR, XRD, SEM, MIP, and compressive strength measurement. Results indicated that hydration products included C-S-H and geopolymer, and both of them were amorphous although there were differences in their structure and morphology. When the dosage of slag was less than 50%, the compressive strength of hardened paste increased as the dosage increased, which was mainly because C-S-H produced by the reaction of GGBFS and alkali filled void in geopolymer phase, and part of unreacted slag particles acting as microaggregate to prevent from extension of microcrack in the hardened paste, so the porosity of hardened paste decreased and compressive strength increased.


2018 ◽  
Vol 20 (2) ◽  
pp. 208-215

The paper presents a laboratory study of concrete mixes based on the alkali-activation of an industrial by-product, ground granulated blast furnace slag (GGBS). A number of factors potentially affecting the resulting concrete quality in terms of workability and strengths were investigated (namely activator type, molarity, curing conditions and times). The statistical significance of the effect of these factors was supported by ANOVA. Higher workability and strengths (with lower activator concentrations) were obtained for KOH containing mixes. Curing at constant moisture and ambient temperature was successful for most alkaline activators and mixes, which showed good concrete strengths at all curing times; when Na2SiO3 was used in addition to NaOH or KOH activators of moderate to high molarity, strengths exceeded those of Ordinary Portland Cement (CEM-I) concrete of a similar water/cement ratio.


2016 ◽  
Vol 249 ◽  
pp. 3-7 ◽  
Author(s):  
Vlastimil Bílek ◽  
Jan Hurta ◽  
Petra Done ◽  
Libor Zidek ◽  
Tomas Zajdlik

Hybrid cements represent a relatively new type of binders which combine some of the advantages of Ordinary Portland Cement (OPC), the application of mineral admixtures and alkali activation. Hybrid cements represent blends containing a low portion of OPC and a high proportion of mineral additions (such as blast furnace slag, fly ash, metakaolin ....). The paper is focused on the study of properties of mortars prepared from hybrid cements. Mortars with hybrid cements were prepared for an evaluation of the effects of the dosage and the composition of alkali activator, the dosage of OPC and the ratio between ground granulated blast furnace slag and fly ash. The results make it possible to optimize the composition of hybrid alkali activated concretes.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5505
Author(s):  
Patrick Ninla Lemougna ◽  
Nicole Dilissen ◽  
Guillermo Meza Hernandez ◽  
Felicite Kingne ◽  
Jun Gu ◽  
...  

Copper slag (CS) remains a challenging industrial by-product with a relatively small utilization fraction. The present study investigated the development of one-part alkali-activated cements based on CS, ground granulated blast furnace slag (GGBS) and a mixture of the two as a precursor. We investigated 5 to 15 wt% solid sodium metasilicate (Na2SiO3) and disilicate (Na2Si2O5) as alkaline reagents. Isothermal calorimetry showed that the reactivity of the system was higher for the metasilicate based samples, with early reaction and higher cumulative heat released. Metasilicate based samples also presented a more densified microstructure, lower porosity and higher strength. Better performances were observed with 10 wt% metasilicate/disilicate with respect to the 5 and 15 wt%. The 28-day compressive strength and elastic modulus of 10 wt% metasilicate samples reached 75 MPa and 25 GPa, respectively, and, for paste samples, ranged from 100 wt% GGBS to 50/50 wt% CS/GGBS. The microstructure and calorimetry of the pastes showed that GGBS actively participated in the binding process, whereas CS played a smaller role and acted as a filler and catalyst. The substitution of commercial GGBS by CS up to 50 wt% did not affect the overall performance, thus, bringing CS forward as an economically interesting precursor.


2003 ◽  
Vol 18 (11) ◽  
pp. 2571-2579 ◽  
Author(s):  
I. Lecomte ◽  
M. Liégeois ◽  
A. Rulmont ◽  
R. Cloots ◽  
F. Maseri

Alkali activation of dehydroxylated kaolin or clay yielded high-strength polymeric materials, so-called geopolymers. They were synthesized by mixing the aluminosilicate with solutions of sodium metasilicate and KOH followed by adding 45 wt.% of ground-granulated blast furnace slag. The influence of the aluminosilicate source, its activation temperature, and the order of mixing raw materials were studied on the workability of the blending paste, the microstructure, and the Vickers hardness of the geopolymer samples. The polymeric material is completely amorphous according to x-ray diffraction. Solid-state 27Al and 29Si magic-angle-spinning nuclear magnetic resonance showed that the geopolymer consists of AlO4 and SiO4 tetrahedra linked together through a polymeric network constituted by branched entities SiQ4(4Al) and SiQ4(3Al), but also by less-polymerized silicates SiQ1 and SiQ2. Scanning electron microscopy showed a homogeneous polymeric gel matrix containing unreacted slag (and quartz) grains; thermogravimetric analysis and differential scanning calorimetry exhibited a high content of water and an elevated melting point (1260°C). Vickers hardness values are in the range of 200 MPa.


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