Papers by Irem Sanal
Cracking of the concrete structures is the major problem in the structural health and durability,... more Cracking of the concrete structures is the major problem in the structural health and durability, and there is a critical need for continuous monitoring and assessing structural integrity. In order to monitor structures, traditional sensors are being used, which have some drawbacks, such only taking recording at specifically determined points. However, it has been shown that unless any existing damage is located at a point of high stress or has severely compromised the integrity of a structure, damages might be undetected. In order to have a more detailed understanding on the behavior of fiber‐reinforced concretes (FRC), their mechanical performance should be evaluated together with local fracture phenomena, such as crack propagation and localization. Because cracking is a major problem in the design and durability of structural elements. In this paper, propagation of cracks in FRC beams under 4‐point bending test is analyzed in detail with an image processing technique, Digital Image Correlation (DIC). DIC technique is applied to further identify fracture parameters such as crack width evolution and crack patterns at different stages of loading, which enables a detailed evaluation of the relationship between fracture parameters and resulting mechanical performance. Therefore, the main aim of this study is to enable the translation of global mechanical response of the FRC beams from the local fracture process, with a detailed characterization of cracks both experimentally and also with DIC analysis, which can be used for structural health monitoring of FRC beams, in terms early stage crack determination and crack monitoring through the lifetime.
Fiber-Reinforced Concrete(FRC) toughness parameters, crucial for structural design, can be obtain... more Fiber-Reinforced Concrete(FRC) toughness parameters, crucial for structural design, can be obtained either by using load–deflection or load–crack opening displacement(COD) relationships. Therefore, determination of midspan-deflection under a given crack width is important in terms of flexural toughness characterization. This research is aimed to determine the relationship between mid-span deflection and COD, depending on beam-thickness/fiber length(t/fL) ratio and fiber aspect ratio(d/fL). In this study, Load-deflection and Load-COD curves from 4-point flexural tests were evaluated in detail to figure out a relationship between the mid-span deflections and crack openings. Proposed relationships were verified with the findings from literature and good results were obtained.
Macrosynthetic fiber–reinforced concrete (MSFRC) has reached maturity as an engineering material ... more Macrosynthetic fiber–reinforced concrete (MSFRC) has reached maturity as an engineering material and is widely being used in some civil engineering applications. However, design approaches for MSFRC are not as well developed as for steel fibers, and there is a need for further research on this new material in order to further help the development of guidelines and increase the practical applications. The main objective of this study is to critically review the present state of knowledge and applications of MSFRC and to study the effect of these fibers on fresh-and hardened-state performance of different concrete mixtures. Seven groups of concrete mixtures were produced with different volume fractions of steel fibers, fly ash, macrosynthetic fibers, and chemical admixture. Mini slump, compression, and flexural tests were conducted on the specimens for evaluating their mechanical performance, and water absorption and sorptivity tests were also conducted for measuring the permeability of these different concrete mix groups. Therefore, with this comprehensive study, a detailed understanding is gained about the present state of applications of macrosynthetic fibers and their potential for being used as a fiber-reinforcement mechanism in concrete elements.
The environmental impact of concrete has become a significant matter of interest because many rea... more The environmental impact of concrete has become a significant matter of interest because many ready-mix concrete producers are now requiring sustainability. Carbon dioxide (CO 2) emissions are often used as an evaluation parameter to identify the environmental impacts of concrete production. However, there are very few reliable estimates available for the practical determination of CO 2 emissions in terms of all concrete constituents at concrete production stage. The aim of this study is therefore to provide data collected from raw-material manufacturers and ready-mix concrete plants so that practical estimates can be made for CO 2 emissions and resulting environmental impacts. Results will be evaluated in terms of raw materials, production, and transportation, in order to identify the potentially significant sources of CO 2 emissions. Emission results from the concrete production with ordinary Portland cement, blended cement and cement replacement with fly ash and slag were also examined, in order to gain further understanding of their efficiency in reducing CO 2 emissions.
The use of radial basis functions(RBFs) in the numerical solution of partial differential equatio... more The use of radial basis functions(RBFs) in the numerical solution of partial differential equations has gained popularity in the engineering and science community as it is meshless and can readily be extended to multi-dimensional problems. RBFs have been extensively used in different context and emerged as a potential alternative for numerical solution of PDEs. In this study, Flow Between Parallel Plates(FBPP) benchmark problem was solved using Multiquadric Radial Basis Function Collocation Method(MQ-RBFCM), then the model results were compared with the analytic ones and the root mean square of the errors between the model and analytic results were calculated. Numerical results are presented for five different cases in which the number of inputs or definitions are increased in order to see whether changing the number of points, makes the results better or not. Also the absolute errors between the results were calculated to have a 3D model of the error rates by plotting them and this has prooved for which cases the solutions by MQ-RBFCM are better. As a result, RBF approach is shown to produce accurate results while requiring a much-reduced effort in problem preparation in comparison to other traditional numerical methods.
Bilindiği gibi çeşitli standartlarda basınç dayanım testleri için kabul edilen numune şekil ve bo... more Bilindiği gibi çeşitli standartlarda basınç dayanım testleri için kabul edilen numune şekil ve boyutları fark gösterebilmektedir. Ancak, zaman ve ekonomik faktörler, zayi olan beton miktarı ve üretilen atığın azalması ve laboratuvarlarda daha düşük kapasiteli beton basınç presi kullanımı göz önünde bulundurulduğunda kalite kontrolünde küçük boyutlarda numune kullanımının daha avantajlı olacağı öngörülmektedir. Bu nedenle, bu çalışma kapsamında, 100 mm'lik küp numune kullanımının pratik uygulamada da arttırılabilmesi için, numune tip ve boyutlarının beton basınç dayanımı üzerindeki etkisinin detaylıca incelenmesi amaçlanmıştır. Bu kapsamda, i) iki farklı kaynaktan alınan, ii) iki farklı karışım içeriğine sahip, iii) dört ayrı beton sınıfına ait, iv) iki ayrı tipte ve v) dört farklı boyuttaki numuneler kullanılarak ölçülen basınç dayanım sonuçları birbirleriyle karşılaştırılmıştır. Böylelikle, basınç deneyinde kullanılan numunelerin şekil ve ebatlarının deneysel sonuçlara olan etkileri geniş kapsamlı olarak değerlendirilmiş ve 100mm'lik küplerin pratikte kullanımının uygunluğu incelenmiştir. Abstract: As is known, in various standards, the acceptable sample size and dimensions for concrete compressive strength tests may differ. However, considering the time and economic factors, the loss of concrete volume and produced waste, and the possible use of lower capacity concrete compression presses in laboratories, it is foreseen that the use of small sample sizes will be more advantageous in quality control of concrete. Therefore, in this study, it is aimed to investigate the effect of sample shape and size on concrete compressive strength so that the use of 100 mm cube samples can be increased in practical application. In this context, the results of compressive strength measured for samples from: i)
This paper presents the second part of a comprehensive study to evaluate the hardened state perfo... more This paper presents the second part of a comprehensive study to evaluate the hardened state performances of SC-FRCCs, which was carried out to understand the effects of various parameters on the mechanical performance of these materials. Main objective of this study was to identify the different behaviors of SC-FRCCs in terms of hardened state performance by considering parameters such as specimen thickness/fiber length ratio (t/f L), fiber type (straight or hooked), and fiber aspect ratio. Specimens were cast using same self-compacting mix designs, only fiber length, fiber type and specimen depth were varied. Four different fiber lengths (6, 13, 35 and 50 mm), two different fiber types (straight and hooked-end) and ten different specimen thickness (from 18 to 100 mm) values were set. As a result, 12 different groups of specimen were obtained. Experimental studies include fiber orientation density, flexural strength, strain localization and crack propagations measurements for hardened state using both traditional methods and a full field image-based method called Particle Image Velocimetry (PIV), which measures surface displacements and strains using digital image analysis. Hardened state tests were carried out with un-notched specimens under four-point bending. Results obtained from both traditional measurement methods and PIV analyses , were combined and used in order to have a detailed understanding on how changing material parameters may affect the material behavior.
The use of high performance fiber-reinforced cement based composites (HPFRCCs) is increasing but ... more The use of high performance fiber-reinforced cement based composites (HPFRCCs) is increasing but still limited due to the lack of standardized methods and models to evaluate performances when different geometries and/or sizes are used. The objective of this study was to investigate the effects of mould constrictions on fiber orientation distribution and resulting mechanical performance. Flow width/fiber length (w/fL) and flow thickness/fiber length (t/fL) were chosen as the 2 parameters/variables for evaluating fiber orientation distribution and mechanical performance. The results showed that varying mould constrictions/dimensions results in different fiber orientation distributions and fiber orientation affects mechanical performance to a certain extent, however, very high variations may be seen in mechanical performance even when two specimens which have very similar fiber orientations are examined. Therefore effects of fiber orientation should be evaluated in combination with oth...
This study focuses on characterization of High Performance Fiber-Reinforced Composites (HPFRCs) u... more This study focuses on characterization of High Performance Fiber-Reinforced Composites (HPFRCs) using a non-contact image based deformation measurement method i.e. Particle Image Velocimetry (PIV). The main objective of the study was to understand the ability of PIV to be used for evaluating various properties of HPFRCs at fresh and hardened states. For this purpose this method was employed together with conventional measurement techniques. Mini-slump flow tests for fresh state and four-point bending tests for hardened state were carried out on specimens, while a high resulotion camera was used to capture successive images during all tests. The results obtained using conventional methods and PIV were compared to have a better understanding of the extent to which PIV can be used for analyzing the behavior of HPFRCs. 1. INTRODUCTION Industrial use of High Performance Fiber-Reinforced Composites (HPFRC) is increasing with an increasing know how of material properties, processes and app...
Construction and Building Materials, 2015
Use of PIV for the fresh and hardened states analyses of concrete materials. Information regardin... more Use of PIV for the fresh and hardened states analyses of concrete materials. Information regarding flow properties and behavior by using displacement vectors and strain fields. Load-crack width opening relations by using PIV and conventional methods. Observation of cracking and cracking patterns by PIV strain field analyses.
Construction and Building Materials, 2013
Flow length and flow thickness affect fiber orientation. Mechanical performance vary depending on... more Flow length and flow thickness affect fiber orientation. Mechanical performance vary depending on fiber orientation state and other factors. The extent to which fiber orientation affect resulting mechanical performance. Implementation of the results on the design of fiber-reinforced cement-based materials.
Construction and Building Materials, 2012
Conference Presentations by Irem Sanal
Concrete is widely used in construction sector and as a resource its consumption is the second la... more Concrete is widely used in construction sector and as a resource its consumption is the second largest on the planet after water, whereas having significant negative impacts on the environment. Regulatory authorities, concrete and cement industries are aware of environmental impacts of concrete and in most cases are making attempts to reduce them. Optimized solution for the concrete industry to have eco-friendly concretes is to obtain a balance between environmental impact and economy. In this research, a comparative study will be made for different types of concretes and results will be evaluated in terms of i) raw materials, ii) production, and iii) transportation, in order to make a detailed CO2 emission identification and classification. The main objective of this study is to identify the key emission sources contributing to CO2 emissions from concrete. First of all, a reporting boundary was selected, where there are three main scopes (Scope 1, 2 and 3) of emissions that will need to be examined within each activity of concrete production stages. Following this, a quantification of the emissions resulting from the production of a cubic meter of concrete is carried out. And finally, various concrete mixtures from 6 differeent concrete plants were compared in terms of CO2 emissions. As a result of this study, the equivalent CO2 emissions generated by a particular concrete with known mix proportions can be estimated using the emission contributions from the several different constituents of concrete.
Uploads
Papers by Irem Sanal
Conference Presentations by Irem Sanal