Theses supervised by Doç. Dr. Mehmet Gesoğlu
21 theses · Gaziantep University
Residual material characteristics of an industrial building after fire
Residual material properties of an industrial building exposed to fire were investigated experimentally in this study. Fire site was divided five part according to visual observation. Site investigation was the first stage of this study and second stage was the laboratory works which were made on steel and concrete core samples taken from industrial building columns. Concrete core samples were tested for residual mechanical properties by compressive strength test. Petrographic examination of cores was made with SEM (Scanning Electron Microscopy), XRD (X-ray Diffraction) and EDX (Energy Dispersive X-ray Spectroscopy) analysis. Reinforcement steel bars were investigated mechanically for tension strength. Mechanical and petrographic examination results were compared with the results in literature. Consequently, concrete lost mechanical, physical, and chemical properties with different deterioration ratios, and the possible temperature changes were between 100°C and 600°C in the industrial building during fire.
Properties of pervious concretes containing processed coarse rubber granules
The objective of this paper was to utilize waste coarse rubber in pervious concrete to produce a sustainable pervious concrete. The pervious concrete in this study was manufactured by replacing single sized natural aggregate with single sized rubber aggregate at six replacement levels of 0, 10, 20, 30, 40, and 50% by total aggregate volume. Two different concrete series were produced at two aggregate-to-cement ratio of 7 and 6. Totally, 12 pervious concrete mixtures were produced in this study. The single sized natural aggregate and waste coarse rubber were passing from 9.5-mm sieve and retaining on 4.5-mm sieve. The pervious concretes were tested for the compressive and splitting tensile strengths, permeability characteristics and abrasion resistance. Moreover, the dry density and void contents of pervious concrete mixtures were determined during the experimental study. The experimental results indicated that the use of rubber significantly enhanced the abrasion resistance of the pervious concrete while it decreased the mechanical properties and permeability characteristics. In addition, replacing single sized natural aggregate with rubber decreased the dry density of the concrete mixtures as well as the void content.
Investigating properties of low binder ultra-high performance concretes containing nano and/or micro silica
This thesis presents the effect of using binary and ternary blends of portland cement, nano silica (NS) and/or micro silica on the mechanical, transport and physical properties of low binder ultra-high performance concretes (UHPC). For this, two concrete groups were designed with and without 10% silica fume (SF) by weight of cement with a water/binder ratio of 0.20 and total binder of 800 kg/m3. Commercially available NS was used in partial substitution of cement at 0, 0.5, 1, 2 and 3% by weight. The results show that among different NS contents at 90 days, UHPC containing 2% NS exhibited the best results for the mechanical property tests. Additionally, UHPCs containing 3% NS exhibited better results for the transport property tests. The results also proved replacing NS with cement decreased both dry and autogenous shrinkage of UHPCs. Furthermore, the group samples of UHPC containing binary cementitious materials (NS and SF) gave better results than concretes containing only NS. The test results also demonstrated the effect of 8 kg/m3 of nano silica with 1% of replacement on the most investigated test properties were almost equal to 10% replacement of micro silica.
An experimental study on the properties of lightweight concrete with cold bolded fly ash aggregate in correlation with normal aggregate concrete
The study presented herein investigates the performance of lightweight and normal weight concretes with similar compressive strengths. For this, two concrete compressive strength values of 25 and 45 MPa were aimed to produce with normal and lightweight aggregates. Totally four concrete mixtures were designed at various water-to-cement ratios and cement contents. The lightweight aggregate utilized in this study was produced through cold bonding pelletization of fly ash and cement in a tilted pan at an ambient temperature. The artificial lightweight aggregate had almost same sieve analysis result with natural aggregate. The concrete mixtures were produced at the same condition and procedure and the test specimens of the mixtures were cured at the same circumstances. After 28-day curing period, the specimens were tested for compressive, splitting tensile, bond and net flexural strengths, modulus of elasticity, electrical resistivity, sorptivity, water absorption, and fracture parameters. The test results indicated that utilization of artificial lightweight aggregates significantly influenced the hardened properties of the concretes. However, increasing the concrete compressive strength decreased the effects of the lightweight aggregate utilization.
Influence of water - binder ratios and volume of micro glass fiber on strength and fracture parameters of ultra high performance concretes
An experimental work was carried out to investigate the effects of high volume micro-glass fibers on the mechanical properties and ductility of Ultra High Performance Fiber Reinforced Concretes (UHPFRCs). The aspect ratio and tensile values of the of micro-glass fibers were 722 and 2000 MPa, respectively. Depending on water per binder ratios (w/b) of 0.12 and 0.14, two groups of UHPFRCs containing 0%, 0.5%, 1%, 1.5%, 2%, 2.5%, and 3% fiber volumes were produced and tested for the compressive strength, splitting tensile strength, modulus of elasticity, flexural strength, load-displacement behavior, fracture energy, and characteristic length. The investigational results revealed that the mixes with 1.5% to 3% of micro glass fibers exhibited the best compressive strength of approximately 160 MPa as well as the highest splitting tensile strength. The results also showed that beyond 1.5 % volume fraction of fiber, the improvement of strength properties began to be constant. On the other hand, the mixes with 3% of micro glass fiber displayed a strain hardening, load- displacement behavior with enhanced ductility.
Effect of using pvc powder on the fresh and rheological behavior of self-compacting concrete
Current study is aimed to find out the effect of using PVC powder on the fresh and rheological properties of self-compacting concrete (SCC). Self-compacting PVC powder concrete (SPC) mixtures were designed with a total binder content of 550 kg/m3 and at a water-to-binder (w/b) ratio of 0.35. Portland cement (PC) was replaced with PVC powder with replacement levels of 0%, 5%, 10%,15%, 20% and 25% by weight in all SPC mixtures. Totally six mixtures were designed and their workability properties were investigated in terms of slump flow diameter, T50 slump flow time, V-funnel flow time, and L-box height ratio. Additionally, the rheological behavior of the SPC was evaluated by using the ICAR rheometer apparatus. Moreover, 56-day compressive strengths of self-compacting concretes containing PVC powder were also examined. From obtained results it can be seen that the utilization of PVC powder into SCC significantly influenced the fresh, rheological and compressive strength characteristics of the SCC mixtures.
Mechanical and fracture properties of ultra high strength concrete reinforced with high volume micro steel fibers
An investigational work was implemented to reveal the effects of high-volume micro-steel fibers (MSF) on the mechanical properties and ductility of Ultra High Performance Fiber Reinforced Concretes (UHPFRCs). The aspect ratio and tensile strength of the MSF used were 37.5 and 2250 MPa, respectively. At water - binder ratios (w/b) of 0.12 and 0.14, two groups of UHPFRCs containing 1%, 1.5%, 2%, 2.5%, 3%, 3.5 and 4% of micro steel fiber by volume and tested for the compressive strength, splitting tensile strength, modulus of elasticity, flexural strength, load-displacement behavior, fracture energy, and characteristic length. The experimental results showed that all mixtures with 4% of MSF demonstrated a compressive strength of greater than 160 MPa, splitting tensile strength higher than 12 MPa, and modulus of elasticity of greater than 43 GPa. On the other hand, the mixes with 4% of MSF exhibited a strain hardening. were achieved with the same range of fiber content and 0.12 w/b,. load- displacement behavior with enhanced ductility and all other fracture parameters well improved significantly.
Effects of binder content and curing type on the mechanical and fracture properties of ultra high strength fiber reinforced concrete
An investigational study was implemented to examine the effects of the different amount of binders on the most mechanical and fracture parameters such as; compressive and tensile strengths, modulus of elasticity, bending, toughness, stiffness, brittleness and ductility of Ultra-High Performance concretes (UHPCs) reinforced with 2% of micro steel fibers for generating Ultra-High Performance Fiber Reinforced Concretes (UHPFRCs). Depending on water curing (WC) and steam curing (SC) of the same water per binder ratios (w/b) of 0.12, two sets of UHPFRCs each of containing 850, 900, 950, 1000, 1050, 1100, 1150, and 1200 kg/m3 binder (85% of cement+15% of silica fume (SF)) were produced and tested for the compressive strength, splitting tensile strength, modulus of elasticity, modulus of rupture, load versus displacement curves, fracture energy, and characteristic length. This study revealed that the mixtures with 1150 kg/m3 of total binder contents exhibited the best results for all tests measured. The results also showed that at 1200 kg/m3 of total binder content, all improvements slightly began to decrease. On the other hand, all mechanical and fractural test results showed that steam cured much preferred than corresponded curing by water.
Mechanical and fracture properties of self-compacting concretes incorporating waste PVC powder
For sustainability, civil engineering industry seeks to execute projects in harmony with nature. This is achieved to some extent by judicious use of natural resources in construction practices. When the plastic waste materials used in daily life complete their lifetime or lost their necessary, they are continuously added to the waste materials in the landfills all over the world and their disposal needs a viable and environmental friendly solution. This has encouraged the use of waste plastic in concrete production, which not only allows for a more efficient life cycle of natural resources but also contributes to environmental protection leading to sustainable development. In this thesis, an experimental study was carried out to investigate the quality of concrete and hardened characteristic of the self-compacting concretes (SCC) made with PVC. A laboratory investigation with a total 6(six) set of mixtures were proportioned having constant water–cementinous material (w/b) ratio of 0.35 and total binder content of 520 kg/m3. Class F fly ash was used as a 20% of total binder content in all mixtures. Polyvinyl-chloride (PVC) powder was employed to replace cement contents of 5, 10, 15, 20 and 25% by volume.
Mechanical properties of boron blended cement concretes
Cement manufacturing process requires high energy consumption. On the other hand, one of the major environmental problems that are faced in this process is the emission of greenhouse gases to the atmosphere. Therefore, the researchers have been investigating the ways to mitigate these problems. During the production of Boron Modified Active Belite (BAB) cement a considerable energy savings and reduced CO2 emission is known to be possible. However the properties of this type of cement have not widely been known, yet. In this, study some mechanical and permeability properties of BAB cement concretes exposed to different initial curing conditions were investigated and compared to those of ordinary Portland cement concretes. Mechanical properties were evaluated through compressive and splitting tensile strength development, while the durability of the concretes was measured by means of rapid chloride penetration and water sorptivity tests. The results showed that mechanical properties of BAB cement concrete, at especially later ages, were slightly better than Portland cement concretes. According to the durability test results, the BAB cement concretes had superior permeability characteristics than the Portland cement concretes
Properties of lightweight and normal weight concretes with similar strength
This thesis addresses an experimental study conducted to investigate the performance of lightweight concrete (LWC) and normalweight concrete (NWC) with similar compressive strength. Lightweight concretes were produced with cold-bonded fly ash aggregates. For this, a dry powder mixture of 90% fly ash and 10% Portland cement by weight was pelletized through moistening in a revolving tilted pan at ambient temperature and cured for 28 days. A total of four concrete mixtures with designed compressive strengths of 25 and 45 MPa were developed for both LWC and NWC, namely LWC25, NWC25, LWC45 and NWC45. The concretes were tested at 28 and 56 days for water permeability, chloride ion permeability, gas permeability, and sorptivity index. On the other hand, compressive strength development of the concretes was observed at 7, 28, and 56 days. The results of comparing LWA with NWC indicated that the compressive strengths of both types of concrete for all ages were almost similar while water permeability of LWC generally slightly higher than that of NWC. Moreover, resistance to chloride penetration, gas permeability as well as sorptivity of LWCs was poorer than NWC.
Use of cold-bonded blast furnace slag aggregate in the production of self-compacting concretes
This study addresses an experimental program carried out to investigate the properties of self-compacting concretes (SCCs) in whichnatural coarse aggregates had been substituted by artificial slag aggregates (ASA). For this, a powder mixture of 90% ground granulated blast furnace slag and 10% portland cement by weight were pelletized in a tilted pan through cold-bonded agglomeration process. The hardened ASAwere tested for specific gravity, water absorption, and crushing strength. Thereafter, they were partially used in producing SCCsin which ASA replaced the natural coarse aggregates in the volume fractions of 0%, 20%,40%,60%,80%, and 100%. Therefore, a total of six mixes with a water/binder ratio of 0.32 were designed and cast using both natural and/or ASA coarse aggregates.Fresh properties of SCCs were observed through slump flow time, flow diameter, V-funnel flow time, and L-Box filling height ratio.Hardened properties of SCCs were measured at 28 and 56 days for compressive strength, splitting tensile strength, chloride ion permeability, gas permeability, andsorptivity. Test results indicated that utilizing of ASA enhance the fresh properties of SCCs, alsoreduce the amount of superplasticizerto achieve a constant slump flow diameter. Moreover, SCCs incorporating ASA displayed better performance than the control mixture in terms of compressive strength, chloride ion penetration, gas permeability, and sorptivity,only the splitting tensile strength had slightly decreasing tendency.Keywords: Artificial aggregate,cold bonding process,ground granulated blast furnace slag, self compacting concrete, transport properties.
Effect of silica fume and steel fiber on the mechnical properties of the conceretes produced with cold bonded fly ash aggregates
ABSTRACTEFFECT OF SILICA FUME AND STEEL FIBER ON THE MECHANICAL PROPERTIES OF THE CONCRETES PRODUCED WITH COLD BONDED FLY ASH AGGREGATESALZEEBAREE, RadhwanM.Sc. in Civil EngineeringSupervisor: Associated. Prof. Dr. MEHMET GESOĞLUJuly 2012, 102 PagesThis study presents an experimental research on the mechanical properties of steel fiber incorporated plain and silica fume (SF) concretes produced with cold bonded artificial fly ash aggregates (AFA). Two concrete series with water-to-binder (w/b) ratios of 0.35 and 0.55 were designed. SF incorporation was achieved by 10% replacement of the weight of cement by silica fume. Two types of hooked-end steel fibers with length/aspect ratios of 60/80 and 30/40 were utilized. AFA, produced from cold bonding pelletization of 90% class F fly ash and 10% Portland cement, were used as coarse aggregate in all of the concrete mixtures. The mechanical properties investigated were compressive strength; splitting tensile strength, modulus of rupture and bonding strength between rebar and concrete. The tests were carried out at the end of 28 day water curing. Analyses of variance of the experimental results were performed and the contributions of the significant factors on the mechanical characteristics of the concretes were determined for statistical evaluations. Moreover, correlation of the experimental data was carried out to monitor the interaction between mechanical properties and bonding strength of the concretes. The results demonstrated that incorporation of SF and utilization of different types of steel fiber reinforcements significantly affected the mechanical properties of the concretes regardless the w/b ratio.Keywords:Cold bonding, Silica fume, Concrete, Mechanical properties, Bonding strength, Steelfiber.
Mechanical and durability properties of self-compacting concrete made with processed waste rubber granules
The study presented herein was carried out to investigate the mechanical and durability characteristics of self-compacting concrete containing waste coarse rubber aggregates (WRA). Two different series of self-compacting rubberized concrete (SCRC) mixtures were designed with a constant water–cementitious material (w/cm) ratio of 0.32 and total cementitious materials content of 550 kg/m3. The first group of mixtures was incorporated binary cementitious blends of 20% flyash (FA) and 80% Portland cement. However, the second series of the mixtures incorporated Ternary cementitious blends of 20% FA with 10% silica fume (SF) and 70% Portland cement. To develop the RSCCs, medium aggregate was substituted by WRA at five designated contents of 0%, 10%, 20%, 30% and 40% by volume in both series of concretes. Totally, 10 concrete mixtures were cast and tested for mechanical and durability related properties such as compressive strength, splitting tensile strength, modulus of elasticity, sorptivity, chloride ion permeability, gas permeability and fracture energy. The tests were conducted at 28 and 90 days after casting. Test results demonstrated that using the rubber particles improved the fracture and ductile properties, whereas aggravated all other measured properties of self-compacting rubberized concretes (SCRCs). However, with the addition of silica fume in to the mixes all mechanical and durability properties enhanced, depending mainly upon rubber content.
Hardened properties of self-compacting concretes prepared with recycled aggregates
The recycled aggregate (RA), self-compacting concrete(SCC) and supplementary cementing materials (SCM) are important for solving the environmental problem related to construction industry. Thus the main objective of this thesis is to investigate the hardened properties of the SCC prepared with recycled coarse aggregates (RCAs) and recycled fine aggregates (RFAs). The hardened properties of self-compacting concretes (SCC) prepared with recycled aggregate is a new research area on which a very limited scientific research has been carried out in the current literature. Natural coarse aggregates (NCAs) and natural fine aggregates (NFAs) of conventional SCC were substituted by RCAs and RFAs at volume fractions of 0% to 100%. Totally, sixteen SCC mixtures were produced and classified into four series; each series included four mixes designed with water to a binder ratio (w/b) of 0.3 and 0.43, respectively. Moreover, silica fume (SF) as a 10% replacement level is also utilized to compare the performance of SCC with and without SF. Hardened properties of SCC were tested for compressive strength, water sorptivity, water permeability, chloride ion permeability, gas permeability, drying shrinkage and restrained shrinkage at 56 days.The results reveal that incorporating RCAs and/or RFAs resulted in a decrease in performance for SCCs due to the high permeable and porous structure. Moreover, durability of SCC made with RAs was generally improved by SF, irrespective of the size of RAs and w/b ratios.
Fresh properties of self-compacting concretes containing waste coarse rubber aggregates
When the plastic materials used in daily life complete their lifetime or lost their necessary, they are continuously added to the waste materials in the landfills all over the world and their disposal needs a viable and environmental friendly solution. Recycled plastic materials is a promising material in the construction industry due to its light weight, elasticity, energy absorption, sound and heat insulating properties. Recycled plastic materials, which are produced form waste plastic materials and used for raw material in industry, have been used in this study to replace the coarse aggregate by weight using different percentages. The paper presented herein was carried out to investigate the workability and rheological properties of self-compacting concretes rubberized concretes with fly ash, with and without silica fume. At a water/binder (w/b) ratio of 0.32, the self-compacting concretes (SCC) were produced by replacing the coarse aggregate with four designated waste rubber contents of 0%, 10%, 20%, 30% and 40% by coarse aggregate volume. Moreover, the SCC with silica fume was produced in second series of mixes by partial substitution of cement with silica fume at varying amounts of 10% and this addition was examined with the relationship of the rubber content. Totally, 10 concrete mixtures were produced and tested for workability related properties such as passing ability, filling ability and rheology. The measured properties of concrete fresh behavior were concrete flow and passing-ability by slump flow, L-box and V-funnel tests. For the rheological testing of fresh SCCs, ICAR rheometer was used to find the rheological parameters. Key words: waste rubber, rheology, self–compacting concrete, silica fume, workability.
Investigating properties of ultra-high performance cementitious composites made with gypsum-contaminated aggregates
The present work aimed to investigate the potential of using gypsum-contaminated fine aggregate in ultra-high performance cementitious composite (UHPCC) to enhance the economic efficiency of this outstanding composite and to provide detailed information on its resistance to internal sulfate attack. For this purpose, three groups of UHPCCs were designed at a constant w/b ratio of 0.174. Two groups of UHPCC mixtures were designed with binary and ternary cementitious blends of Portland cement, silica fume, and/or ground granulated blast furnace slag and were reinforced with 2% micro steel fibers by volume. The other group was designed with binary cementitious blends of Portland cement and silica fume and was prepared without fibers. Each group consisted of five mixes with different SO3 contents of between 0.11% and 4.5% by weight of natural sand. For each mix, the UHPCC samples were either standard cured or steam cured at 80 ˚C over a 48 h. The UHPCC samples were tested for compressive strength, splitting tensile strength, expansion, drying shrinkage and weight loss. The experimental findings were also supported by SEM, EDX, and XRD investigations. Besides, UHPCCs were compared to Portland cement mortars in terms of compressive strength, expansion, and microstructure. Test results indicated that UHPCCs generally showed an increase in compressive strength, particularly under steam curing and an insignificant expansion even in the presence of excess sulfates, in contrast to mortars thus suggesting the excellent resistance of UHPCC to the internal sulfate attack.
Use of soft computing techniques for predicting shear strength of adhesive anchors
ABSTRACTUse of Soft Computing Techniques for Predicting Shear Strength of Adhesive AnchorsMuhammet Enes YılmazM. Sc. in Civil EngineeringSupervisoor: Associated Prof. Dr. MEHMET GESOĞLUJanuary 2013, 44 pagesThis paper reports the results of an analytical study to predict the edge breakout shear capacity of single adhesive anchors post-installed into uncracked hardened concrete. For this purpose, an experimental database for the adhesive anchors compiled by the ACI Committee 355 was obtained and utilized to construct training and test sets so as to derive the closed-form solution by means of gene expression programming (GEP). The independent variables used for development of the prediction model were anchor diameter, type of anchor, edge distance, embedment depth, clear clearance of the anchor, type of chemical adhesive, method of injection of the chemical, and compressive strength of the concrete. The generated prediction model yielded correlation coefficients of 0.98 and 0.92 for training and testing data sets, respectively. Moreover, the performance of the proposed model was compared with the existing models proposed by American Concrete Institute (ACI) and Prestressed/Precast Concrete Institute (PCI). The analyses showed that the proposed GEP model provided much more accurate estimation of the observed values as compared to the other models.Keywords: Adhesive anchors, Genetic programming, Modeling, Shear capacity
Internal curing of high strength concrete by using cold bonded aggregates
This study aims at examining experimentally the shrinkage and mechanical properties of High-Strength Concrete (HSC) containing blast furnace slag aggregates (ASA) and artificial fly ash aggregates (AFA) that are employed as water reservoirs to enable internal curing. So as to form fly ash and/or slag aggregates, a dry powder blend of 10% of Portland cement and 90% fly ash or slag was initially pelletized by moisturizing at room temperature in a spinning skewed pan; these were subsequently cured for 28 day. Applying a 0.28 water-to-cement ratio, nine HSCs mixtures were developed with different ASA or AFA replacement levels, i.e. 0%, 5%, 10%, 15%, and 20%. After 28 day, testing of the hardened concretes was conducted for splitting tensile strength, compressive strength, and modulus of elasticity. The concrete was monitored for a 57 day drying period to determine the restrained shrinkage, autogenous shrinkage, and drying shrinkage along with the water loss. The HSCs having 20% ASAs showed the highest mechanical properties. Additionally, HSCs containing ASA showed a longer cracking period of the concretes causing finer cracks that are linked to the lower free shrinkage. Largely in the HSCs containing 20% AFA, there was, however, a noticeable decline in the autogenous shrinkage for all the HSCs with AAs, especially for HSCs with 20% AFA.
Properties of self-compacting concretes made with cold bonded fly ash lightweight aggregates
In this thesis, an experimental program was conducted to investigate some mechanical, fracture, physical and durability properties of self-compacting concretes made with cold bonded fly ash aggregates. At first, dry powder mixture of 90% fly ash and 10% Portland cement by weight was pelletized through moistening in a revolving tilted pan at ambient temperature to produce lightweight fly ash aggregates which were then cured for 28 days. Thereafter, a total of seventeen self-compacting lightweight aggregate concretes (SCLCs) in which natural aggregates had been replaced with cold-bonded lightweight fine (LWFA) and coarse aggregate (LWCA) at different volume fraction of 10%, 20%, 30%, 40% and 50% were designed with a water/binder ratio of 0.32. The workability of SCLCs was observed through by slump flow time and diameter, V-Funnel flow time, and L-Box height ratio. Moreover, the rheological properties of fresh concrete mixes were determined via ICAR rheometer. Thereafter, the hardened properties of the concretes were measured by means of compressive strength, splitting tensile strength, fracture energy, water sorptivity, water permeability, rapid chloride permeability, and gas permeability tests. In addition, physical properties such as drying shrinkage, weight loss and the restrained shrinkage cracking were monitored.
Investigating the mechanical and fracture properties of rubberized concretes
The mechanical and fracture properties of rubberized concretes were investigated experimentally in this study. The concretes were produced with two types, crumb rubber and tire chips, of waste scrap tire rubber. The crumb rubber and tire chips were replaced with fine and coarse aggregate, respectively. The each type of rubber was replaced with aggregate by six replacement levels of 5, 10, 15, 20, 25 and 30% in the rubberized concrete productions. The mechanical properties of the rubberized concretes investigated through compressive strength, splitting tensile strength, steel-concrete bond strength, flexural strength, and modulus of elasticity, besides the fracture properties were examined according to fracture energy and characteristic length. The results indicated that utilization of rubber significantly affected the mechanical properties of concrete as well as fracture properties. The compressive strength and modulus of elasticity of concretes decreased with increasing the rubber content. However, it was that utilization of rubber increased the ductility of concrete during compressive failure. Keywords: Concrete; Fracture energy; Mechanical properties; Tire rubber