Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ2Drying Shrinkage and Microstructural Properties of Geopolymers Including Steel and Iron Particles
Gulmez, Nihan; Kockal, Niyazi Ugur
Geopolymer mortars show significantly higher shrinkage than normal Portland cement mortars. So, one of the most important disadvantages of these promising alternative binding materials for their wider applications is the cracking occurring by shrinkage. Different inserts and fibers are used in fresh mixtures in order to control drying shrinkage cracks and to provide mechanical capacity. The aim of this study is to investigate the effectiveness of using both metal particles (iron particles) and metallic fibers (steel particles) in geopolymer composites to reduce drying shrinkage. In addition, microstructural properties of composites were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses and causes of shrinkage were investigated in detail. Mixtures containing 20% silica fume have 38.4% lower drying shrinkage than slag-based mixtures. In slag-based composites, decreases in drying shrinkage were found as 18.8% and 49.1% when adding 10% iron particles or 10% steel particles compared to metal-free composites.
- MakaleYalnız künye2021Scopus SJRQ3Effects of iron powder on properties of geopolymers subjected to different curing regimes
Gulmez, Nihan; Kockal, Niyazi Ugur
Silica fume, slag and iron powder are by-products from various industries. In parallel with development of industrial technology, it is also known that these by-products which cause rapid pollution of the environment are also harmful to human health because they are easily respirable. For this reason, a series of experiments were carried out to determine physical and mechanical properties on samples prepared using different blend designs to examine the effect of factors such as curing conditions, binder type and waste iron powder content. Percentages of iron powder added to replace the aggregate are 10%, 20%, 30% and 40% by volume of slag aggregate. It was observed that the substitution of 30% by volume iron powder instead of slag in geopolymer mortars is the most effective in increasing splitting tensile strength. For 40% partial replacement of fine aggregates with iron powder, increases in compressive strength and flexural strength of slag-based mortars were 7.2% and 43.4%, respectively, compared to mortar without iron powder at 60°C curing conditions.
AtıfScopus4
İncele - MakaleYalnız künye2020Scopus SJRQ1Roles of aluminium shavings and calcite on engineering properties of cement-based composites
Gulmez, Nihan
In the construction industry, which large amounts of raw materials are consumed, substituting even small parts of concrete components with waste materials may lead to significant savings in consumed energy and natural resources hence support prevention of environmental pollution. In this study, an experimental program was carried out to find a reliable and eco-friendly method for eliminating large quantities of calcite powders originating from the marble processing industry and also aluminium shavings, a nondisposable product of metal working and shaping industry. Physical, mechanical and microstructural properties of the mortars produced with industrial wastes at different replacement percentages were evaluated. Adding up to 20% calcite to the mortar mixtures instead of cement did not cause a significant change in water absorption values compared to control mortar. In addition, the gradual increase of aluminium shavings in all mortar mixtures resulted in a significant decrease in apparent porosity. In mortars based on 10% calcite, an increase of 52% in 7-days flexural strength was achieved with the addition of 4% aluminium shavings.
AtıfScopus23WoS20OpenAlex24
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