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- ArticleAçık Erişim2025İnşaat ve Yıkıntı Atıklarından Elde Edilen Lif Takviyeli Geri Dönüştürülmüş Kumların Mekanik Davranışı Üzerine Bir Çalışma
Akoğuz, Harun
Bu çalışmada, inşaat ve yıkıntı atıklarından elde edilen geri dönüştürülmüş beton agregası ve atık tuğla tozunun, farklı karışım oranları ve alkali çözeltisi molariteleri etkisi altındaki mukavemet ve geçirimlilik özellikleri incelenmiştir. Bu amaçla, alkali çözeltisi karışımı-geri dönüştürülmüş zemin %15, %20, %25 ve %30 oranlarında karıştırılmıştır. Alkali ortamın etkisinin belirlenebilmesi amacıyla da alkali çözeltisi molaritesi 0,5M, 1M, 1,5M, 2M ve 2,5M olarak uygulanmıştır. Lif katkısı ise sabit bir oranda, 10 mm, 15 mm ve 20 mm uzunluğunda uygulanmıştır. Sonuçlar, serbest basınç mukavemeti ve geçirimlilik deneyleri ile değerlendirilmiştir. Ayrıca, serbest basınç mukavemeti test sonuçlarından elde edilen, maksimum serbest basınç mukavemeti ve maksimum mukavemete karşılık gelen birim şekil değiştirme değerleri dikkate alınarak zemin örneklerinin yük altındaki davranışları da incelenmiştir. Bu çalışmanın sonuçları, karışım oranlarının serbest basınç mukavemeti üzerinde etkili olduğunu ve karışım oranı arttıkça mukavemet değerlerinin arttığını göstermiştir. Alkali çözeltisi molaritesinin artmasının, karışım oranlarına nispeten mukavemet artışında daha etkili olduğu ve karışım oranı arttıkça bu etkinin daha da arttığı belirlenmiştir. Lif katkısının hem maksimum mukavemet değerlerinde hem de bu değerlere karşılık gelen birim şekil değiştirme değerlerinde artış sağladığı ve zeminin yük taşıma kapasitesi ve davranışında olumlu etkiler meydana getirdiği gözlemlenmiştir.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025Evaluation of long-term reinforcement of soils using waste brick powder: Insights from strength and characterization
Naldan, Ahmet; Akoğuz, Harun; Çağlar, Bülent
This study presents an investigation into the reuse potential of waste brick powder (WBP), a cost-effective, environmentally friendly, and easy-to-use waste-based geopolymer for soil improvement as a grouting material. The WBP was obtained by crushing and sieving waste brick to produce the recycled aluminosilicate starting material. Various factors, including liquid-to-solid ratios (1.5, 2.0, and 2.5), NaOH molarities (4, 8, 12, and 16), types of soils, and aging (7, 28, and 365 days), were comprehensively investigated to gain insight into the usability of WBP in soil injection. The effect of alkali-activated waste brick powder (AAWBP) on the mechanical strength and injectability of the soils was assessed, as well as the influence of these factors on the microstructure of samples. The primary structure of AAWBP was determined to be the C-S-H gel, which significantly enhanced the strength development of soil samples. The compressive strength of geopolymer-treated S1, S2, and S3 soil samples reached 4.72, 3.79, and 2.5 MPa after 365 days, respectively, significantly higher than the samples at 28 days (3.32, 1.00, and 0.61 MPa, respectively). Moreover, the strength of samples increased with a decrease in the liquid-solid ratio in all samples, whereas it increased with a rise in the concentration of the activator up to 8 molar for S2 and S3 soil and up to 12 molar for S1 soil. Also, reducing soil particle size positively influenced the development of strength characteristics.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Comparative Study of Mechanical and Microstructural Properties of Biocemented Sandy Soils Enhanced with Biopolymer: Evaluation of Mixing and Injection Treatment Methods
Şimşek, Mutlu; Çelik, Semet; Akoğuz, Harun
Soil improvement is one of the fundamental practices in civil engineering, with a long-standing history. In today’s context, the rapidly increasing demand for construction driven by urbanization has further emphasized the necessity and significance of soil stabilization techniques. This study aims to determine the optimum parameters for improving sandy soils by incorporating sodium alginate (SA) as a biopolymer additive into the microbial calcium carbonate precipitation (MICP) process. Sand types S1, S2, and S3, each with distinct particle size distributions, were selected, and the specimens were prepared at medium relative density. Three distinct approaches, MICP, SA, and MICP + SA, were tested for comparison. Additionally, two different improvement methods, injection and mixing, were applied to investigate their effects on the geotechnical properties of the soils. In this context, hydraulic conductivity, unconfined compressive strength (UCS), and calcite content tests, as well as scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses, were performed to assess the changes in soil behavior. SA contributed positively to the overall efficiency of the MICP process. The study highlights SA-assisted MICP as an alternative that enhances the microstructural integrity of treated soils and responds to the environmental limitations of conventional methods through sustainable innovation.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025Eco-Friendly Stabilization of Coarse-Grained Soil Using Gum Rosin and Natural Fiber
Akoğuz, Harun
Cement and its derivatives are frequently used as traditional construction materials for soil improvement. However, the most commonly used ordinary Portland cement can significantly affect the ecological environment. This study proposes an innovative alternative improvement method to stabilize soil by incorporating gum rosin (GR), a natural polymer, into the soil. For this purpose, the improvement of soil with different grain diameters (G1 and G2) by incorporating different proportions of sisal fiber (0.2%, 0.4%, 0.6%, and 0.8%) into different proportions of GR (5%, 10%, and 15%) was investigated. The focus of the study was the treatment of GR natural polymer to the soils by heating as an innovative method and to determine the characteristic changes in the strength and permeability of the soil. Firstly, the setting time of this method was determined. After that, unconfined compressive strength (UCS), ultrasonic pulse velocity (UPV), and permeability tests were performed on the samples subjected to different curing times (1, 7, and 28 days). According to the results obtained from the experiments, it was determined that the setting time of the samples reached a stable state after one day of curing. The average strengths of G1 and G2 soils were 3.72 MPa and 2.48 MPa, respectively, and it was observed that the decrease in grain diameter contributed positively to the increase in strength. In addition, it was determined that both the strength and the failure stress increased with the inclusion of fiber. Moreover, a high coefficient of R2 = 0.9428 was obtained from the variation of the UPV test and UCS test, and the usability of the UPV test results in estimating the strength was evaluated. According to the permeability test results, a negligible decrease in permeability was observed after the treatment, and in this case, it was evaluated that this method could be used in many different engineering fields, such as permeable asphalt pavements. The findings suggest that this natural polymer may have potential in certain engineering applications, though its wider use requires further exploration.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Performance evaluation of waste glass in soil improvement: Influence of particle size of waste glass on mechanical, microstructural, and durability characteristics
Akoğuz, Harun
The accumulation of waste glass (WG) from construction and demolition waste is detrimental to the environment due to its imperishable nature; therefore, it is crucial to investigate a sustainable way to recycle and reuse the WG. To address this issue, this study examined the mechanical strength, microstructural characteristics, and environmental durability—specifically under wet-dry (WD) and freeze-thaw (FT) cycles—of WG obtained from construction and demolition waste, with a focus on its suitability as a binding material for soil improvement applications. Firstly, sand and WG were mixed, and an alkali solution was injected into the mixture, considering various parameters, including WG particle size, mixing proportions, sodium hydroxide (NaOH) concentration, and curing time. Subsequently, the effect of WG grain sizes on micromorphology characteristics and mineralogical phases was evaluated before and after the treatment through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and ultrasonic pulse velocity (UPV). The results revealed that reducing the WG particle size and increasing the WG/S ratio significantly improved the strength of the WG-treated samples. Additionally, decreasing the NaOH concentration and extending the curing time also positively influenced their strength. The UCS test results indicate that the particle size of WG significantly influenced the strength development of the samples, as the maximum compressive strength increased from 1.42 MPa to 7.82 MPa with the decrease in particle size. Although the maximum UCS values of the samples varied with different WG particle sizes, the values exceed the minimum criterion of 0.80 MPa required for use as a road substructure, as specified in the ASTM D4609 standard. Moreover, as WG grain size decreased, more geopolymer gels formed, continuing to fill the voids and making the overall structure denser, and the changes during geopolymerization were confirmed by XRD, SEM, FTIR, and UPV analysis. The optimum WG/S ratio was found to be 20 %, with strength increasing by approximately 3.88 times higher as the WG/S ratio shifted from 5 % to 20 %. In addition, the optimum NaOH concentration was determined to be 10 M, as higher molarities led to a decrease in strength. Moreover, UPV results indicate that WG-treated sand soils exhibited UPV values 9.4–13 times greater than untreated soils. The WD and FT test results indicate that WG-treated samples experienced more rapid disintegration in the WD cycle than in the FT cycle; however, a decrease in WG particle size resulted in reduced disintegration effects in both WD and FT conditions. In both the FT and WD cycles, the declining trend exhibited a stable tendency around the eighth cycle. Nevertheless, the WD cycling damage considerably intensified disintegration, causing a profound deterioration in the structural integrity of the samples. As a result, repeated WD cycles lead to the formation of microcracks, which progressively weaken soil aggregation and reduce the overall strength of the samples. Consequently, this green and simple soil improvement technique can provide more inspiration for reducing waste and building material costs through efficient use of construction and demolition waste.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Investigation of Freeze-Thaw Properties of High Plasticity Clay Soil Improved with Lime and Sodium Alginate Biopolymer
Akoğuz, Harun; Teber, Dilber
In this study, the effect of sodium alginate biopolymer and the effectiveness of sodium alginate biopolymer combined with lime in improving a high-plasticity clay soil were investigated. For this purpose, 0%, 0.5%, 1%, and 1.5% biopolymers and 0%, 2%, 4%, and 6% lime were added to the clay soil. At the end of the 7 and 28 day curing period, the strength results were evaluated with unconfined compressive strength tests. In order to examine the effects of environmental factors, the improved soil samples were exposed to freeze-thaw cycles for 5 and 10 cycles. As a result, it was observed that sodium alginate biopolymers had higher unconfined compressive strengths compared to pure samples at the end of the curing periods. As a result of freeze-thaw cycles, it was determined that the biopolymer additive improved the strength results. When using biopolymer with lime, it was determined as a result of strength tests and freeze-thaw cycles that biopolymer increased the effectiveness of lime in soil improvement. As a result, it has been evaluated that sodium alginate, an environmentally friendly biopolymer, may have positive contributions to engineering applications in the improvement of clay soils.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024The experimental investigation of seepage control in different sand soils using photopolymerization
Akoğuz, Harun
Seepage control is critically essential for dams, slopes, and the stability of many engineering structures, developing over many years using different methods. This study presents a novel approach for seepage control using the photopolymerization technique to form an impermeable crust at the soil surface. Effects of exposure duration (5, 10, 15, and 30 min) and light intensities (140, 550, 710, and 1000 W/m2) on the seepage control effectiveness of four different sand soils were investigated by using the photopolymerization technique. The three-point bending, permeability and acid rain simulation tests were performed to illustrate the effect of photopolymerization on the seepage control of sand soils. Furthermore, the influence of photopolymerization on the microstructure of soils was examined with the aid of SEM analysis. The results indicated that the photopolymerization technique could improve the crust strength, acid rain durability, and permeability of sand soils. The crusts at the surface layer of soils were formed after the photopolymer was applied to the sand surface and then exposed to UV light. These crusts of different soils have bending strengths and thicknesses in the range of 34.57 and 68.07 MPa, 2.13 and 6.18 mm, respectively. The increase in exposure duration and light intensity, resulted in the gradual increment of soil crust thickness. On the other hand, the increase in light intensities have more effective on the crust thickness. The formed soil crust has been provided an impermeable surface that prevents the weight loose from the surface of the soil under acid rain conditions. The SEM analysis indicated that the photopolymerized gels were homogeneously distributed between the grains in all samples, although the grain distribution of soils were different. Since the photopolymerization method has a short treatment duration and is easier to apply on the sand surface, the occurrence of the crust at the soil surface by this technique may open a new and improvable path for seepage control. The obtained results showed that the photopolymerization method is promising for repairing, restoring, and strengthening the construction materials in different engineering areas, as well as seepage control.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2023Mikrobiyal Aracılı Kalsit Çökelmesi (MICP) Tekniğinde Çimentolama Solüsyonu Enjeksiyonuna Sodyum Aljinat Yoğunluğunun Etkisinin İncelenmesi
Akoğuz, Harun
Günümüzde zeminlerin iyileştirilmesi için birçok farklı metot kullanılmaktadır. Bu metotların birçoğu çevreye zararlı bileşenler içerdiğinden alternatif zemin iyileştirme yöntemlerine ihtiyaç duyulmaktadır. Bu kapsamda zemin iyileştirme yöntemlerine çevreci bir yaklaşım olarak ortaya çıkan Mikrobiyal Aracılı Kalsit Çökelmesi (MICP) tekniği ile zeminlerin mühendislik özellikleri iyileştirilebilmektedir. Ancak MICP tekniği ile zeminlerin iyileştirilmesinde karşılaşılan problemlerden biri uygulama süresidir. Uygulama süresi genelde oldukça fazla olan MICP tekniği için farklı uygulamalara ihtiyaç duyulduğu anlaşılmaktadır. Bu amaçla çalışmamızda çimentolama solüsyonuna (kalsiyum klorür) ilave edildiğinde uygulama süresini azaltabilecek bir biyopolimer türü olan sodyum aljinatın enjeksiyon özellikleri incelenmiştir. Farklı yoğunluklarda hazırlanan sodyum aljinat solüsyonu zemine enjeksiyon yöntemiyle verilerek zemin içerisindeki dağılımı uygulama süresince takip edilmiş ve sonuçlar permeabilite deneyi ve Taramalı Elektron Mikroskobu (SEM) analizi ile değerlendirilmiştir. Sonuç olarak çimentolama solüsyonuna ilaveten sodyum aljinat kullanımının tüm yoğunluklarda (0.1 g/l, 0.3 g/l, 0.6 g/l) permeabilite üzerinde olumlu sonuçları olmuştur. Daha düşük yoğunluklarda ise (0.1 g/l) uygulama süresi biraz daha artmış ancak daha iyi geçirimlilik sonuçlarıyla beraber daha homojen bir dağılım elde edilebilmiştir. SEM analizleri sonucunda oluşan jel yapının taneler arasında bağ oluşturduğu gözlemlenmiştir. MICP tekniği ile zeminlerin iyileştirmesinde düşük yoğunluklarda (en fazla 0.1 g/l) sodyum aljinat kullanımının uygulama süresine olumlu etkisinin olabileceği değerlendirilmiştir.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2019THE EFFECTS OF DIFFERENT SOURCES OF CALCIUM IN IMPROVEMENT OF SOILS BY MICROBIALLY INDUCED CALCITE PRECIPITATION (MICP)
Akoğuz, Harun; Çelik, Semet; Bariş, Özlem
Several soil improvement techniques are successfully implemented today. Studies are increasingly becoming popular on microbially induced calcite precipitation (MICP) as an environment-friendly and sustainable method that is an alternative to other soil improvement techniques. Our study examined the effects of different sources of calcium on an improvement that was carried out on a sand soil with a 35% relative density by using the MICP method. The results were analyzed by using unconfined compression, permeability, calcite formation percentage, pH, SEM (scanning electron microscopy) and XRD (x-ray diffraction) experiments. As a result of the unconfined compression test, the strength values were obtained as 2406 kPa in the specimens where calcium chloride was used as a calcium source, 2435 kPa in the specimens where calcium nitrate was used and 64 kPa in the specimens where calcium acetate was used. The permeability experiment revealed a decrease in permeability of 80.8% for calcium chloride, 23% for calcium nitrate and 90.4% for calcium acetate. According to the results of the SEM analyses, the structures that formed in all specimens bound the grains to each other and coated the surfaces of the grains. In the XRD analyses, calcite formation was observed in the specimens where calcium chloride and calcium nitrate were used as the source, while, in contrast, vaterite formations were also observed in the specimens where calcium acetate was used as the source. It was determined that different sources of calcium had different effects on improvement of sand soils by microbially induced calcite precipitation (MICP).
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