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- MakaleYalnız künye2026Scopus SJRQ1Analysis of microstructural properties and durability characteristics of geopolymer mortars with mining waste
Aksüt, Yavuz Selim; Kaya, Yusuf; Sünnetçi, Kadir
The growing environmental concerns over resource depletion and carbon emissions from cement production have accelerated the search for sustainable alternatives to conventional concrete. In this context, geopolymers have emerged as promising binders, particularly through the utilization of aluminosilicate-rich industrial wastes to reduce environmental impact and support waste recycling. This study examines the mechanical and durability properties of geopolymer mortars produced by partially replacing ground granulated blast furnace slag (GGBFS) with mining waste (MW) at ratios of 0%, 10%, 20%, and 30%. The mixtures were activated using 10 M sodium hydroxide and sodium silicate under standard water curing conditions. Mechanical strength, ultrasonic pulse velocity (UPV), freeze–thaw resistance, and sulfate durability were evaluated. The optimum performance was obtained with 20% MW, which achieved a 30.4% increase in flexural strength and 18% in compressive strength at 7 days. This mixture also showed the lowest mass (10.69%) and strength loss (18.36%) after 50 freeze–thaw cycles. Scanning electron microscopy analysis confirmed enhanced gel formation and microstructural densification. The findings demonstrate that controlled use of MW not only improves durability but also promotes sustainable binder development in geopolymer technology.
AtıfScopus1OpenAlex1İncele - MakaleYalnız künye2025Scopus SJRQ1Durability properties of fiber-reinforced geopolymer concrete with natural and industrial waste mineral admixtures
Aksüt, Yavuz Selim; Çullu, Mustafa; Yetgin, Şükrü
In this study, ground granulated blast furnace slag (GGBFS) and quarry rock dust (RD), both industrial and natural mineral wastes were used as binder materials in geopolymer concrete. The influence of these mineral admixtures on the concrete’s durability under aggressive environmental conditions was investigated. Steel, polyester, and hybrid fibers were incorporated at volume fractions of 0%, 0.25%, 0.50%, 0.75%, and 1.0% to further enhance durability performance. Freeze-thaw and sulfate resistance tests were carried out to evaluate the effects of fiber type and content on the durability behavior of the geopolymer concrete. The test results showed that the mineral waste-based binder system itself offered considerable durability while the addition of fibers significantly improved resistance to freeze-thaw cycles and sulfate attacks. Among all types, the geopolymer concrete with 0.5% polyester fiber exhibited the highest resistance to freeze-thaw while hybrid fiber usage provided a balanced enhancement across both test environments.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2024Scopus SJRQ1Effect of White-Portland cement containing micro and nano silica on the mechanical and freeze-thaw properties of self compacting mortars
Etli, Serkan; Yılmaz, Tekin; Hansu, Osman
This study concentrated to investigate the influences of white-Portland cement (W-PC) containing silica fume (SF: micro-silica (µSi) and nano-silica (nSi)) as replacement (2–4 wt%) on mechanical (strength and durability), physical and microstructural behaviors of self-compacting mortars (SCMs) fabricated at 0.48–0.63 w/b ratios. In keeping with these purposes, besides of carrying out the workability (mini-slump flow: M−SF and V-funnel: V-F) experiments of SCMs, the mechanical and microstructural tests implemented were: unconfined compressive strength (UCS), flexural strength (FS), freeze–thaw (F-T) and scanning electron microscope (SEM) analysis. The outcomes displayed that, in comparison with the control, replacing W-PC by SF (particularly nSi) enhanced the UCS and FS, resisted against F-T durability by lowering the strength losses in UCS and FS. The ameliorated microstructure resulting in a reduction in the number and/or a narrowing in the size of micro-cracks and pores contributed to generate a more compact and consolidated SCM structure for the improving of strength and durability due of pore-filling effect and superior pozzolanic characteristics of µSi and especially nSi, this in turn reduced the permeability of SCM, which has a significant effect on the strength and durability behaviors of the SCM.
AtıfScopus16WoS16OpenAlex19İncele - MakaleAçık Erişim2024Scopus SJRQ2Superplasticizer Dosage Effect on Strength, Microstructure and Permeability Enhancement of Cementitious Paste Fills
Cavusoglu, Ibrahim
A cementitious paste fill (CPF) ensures the long-age stability of underground cavities. Recently, superplasticizers, specifically ones that are polycarboxylate ether-based, have been incorporated to enhance CPF performance, yet their long-term effects on permeability, mechanical properties, and microstructures remain unclear. This study investigates these effects with CPF samples containing varying superplasticizer dosages (0%, 1%, 3%, 5%) that have been cured for up to 150 days. Rheological assessments (slump cone, vane shear tests), unconfined compressive strength testing, microstructural characterization (MIP, SEM), and hydraulic conductivity measurements were performed alongside XRD and thermal analyses (TAns) on high w/c (2) cement paste samples. The results showed that superplasticizer addition reduced CPF water content by 23% and yield stress by six times, aiding slurry transport. Long-term strength was enhanced by up to 2.4 times compared to the control samples, indicating improved underground stability. Superplasticizers altered the CPF samples stress–strain responses, increasing their load-bearing capacity. TG/DTG and XRD analyses revealed that hydration product development increased and porosity decreased in the presence of a superplasticizer. Hydraulic conductivity and permeability also decreased significantly. SEM and MIP analyses showed that the superplasticizer enhanced denser microstructures with fewer pores and fractures. These findings offer promising implications for designing CPFs with improved strength, durability, and environmental sustainability.
AtıfScopus14WoS11OpenAlex12İncele - MakaleYalnız künye2011Scopus SJRQ1Abrasion Resistance of Cement Mortar with Different Pozzolanic Compositions and Matrices
Yetgin, Sukru; Çavdar, Ahmet
Abrasion of concrete occurs due to scraping, rubbing, skidding, or sliding of objects on its surface. The abrasion resistance of concrete is influenced by a number of factors, such as compressive strength, surfacing finish, aggregate properties, types of hardeners, and curing. The main objective of this study is to determine the effects of the pozzolanic compositions and matrix structure (or voids) on the abrasion resistance of cement mortars. In this study, the mortars produced with cement samples with seven different compositions and varied with an air-entraining agent were subjected to the abrasive effects. Several examples of mortars were evaluated using samples cured for six different periods throughout 1 year. This study is supported by thin section investigations, in addition to being subjected to the basic tests, such as compression, flexure, and abrasion. The Bohme apparatus was used during abrasion tests. To summarize the most important findings from this study, a compact cement matrix is more effective against abrasive effects than mineral additives.
AtıfWoS13OpenAlex18İncele - MakaleYalnız künye2010Scopus SJRQ1Investigation of mechanical and mineralogical properties of mortars subjected to sulfate
Çavdar, Ahmet; Yetgin, Şükrü
The durability can be described as concrete's resistance to the destructive influences of a medium containing acid, sulfate and/or various chemicals and mechanical effects. The main objective of this study is investigation of mechanical and mineralogical properties of cement mortar with different pozzolanic compositions and subjected to sulfated medium. In the study, the mortars produced with cement samples having seven different compositions and varied with an air-entraining agent were subjected to the influence of sulfate. This study is supported by thin section and X-ray powder diffraction (XRPD) investigations, in addition to being subjected to the basic tests, such as compression and flexure. The most important findings obtained from the study are that the compact structure has more effective properties against sulfate effects for cement mortars than pozzolanic materials' effects and the highest pozzolanic material ratio is restricted about 25-30% by mass because this ratio is a boundary of mechanical properties.
AtıfScopus34WoS29OpenAlex37İncele - MakaleYalnız künye2010Scopus SJRQ1Investigation of abrasion resistance of cement mortar with different pozzolanic compositions and subjected to sulfated medium
Çavdar, Ahmet; Yetgin, Şükrü
The durability phenomenon for concrete, or cement mortar, has gained attention recently as one of the important mechanical properties. It can be described as concrete's resistance to the destructive influences of a medium containing acid, sulfate and/or various chemicals and mechanical effects, like abrasion. Most of the studies attempted to improve these individual properties in concrete. However, concrete can be subjected to two or more of these effects simultaneously. In this study, the mortars produced with cement samples having seven different compositions and varied with an air-entraining agent were subjected to the influence of sulfate and abrasive effects simultaneously. In this study, several examples were evaluated using samples cured for six different periods throughout one year. This study is supported by thin section and XRPD investigations, in addition to being subjected to the basic tests, such as compression, flexure and abrasion. If the most important findings obtained from the study are summarized, it is seen that a compact cement matrix is more effective against both sulfate and abrasive effects than mineral additives. The mortars subjected to coupled (sulfate and abrasive) effects show less durability if compared to ones cured in water and later abraded.
AtıfScopus31WoS27İncele