Gökhan Kaplan

The Optimization of Calcareous Fly Ash-Added Cement Containing Grinding Aids and Strength-Improving Additives

This is an experimental study which explores the physical, mechanical, and economic factors involved in the production of type CEM II A-B/W cement. In this context, 4 cement additives were used in two different dosages (200 and 800 g/t). Class C fly ash was used for composite cement production at ratios of 5%, 20%, and 35%. It was shown that Blaine fineness increases with the increasing fly ash content. The use of fly ash at ratios of 5% and 20% was not found to have any unfavorable effects on the compressive strength at the early days. It is found that the use of additive for improving the early-age strength is preferable when fly ash is used. It is possible to produce Class 52.5 N cement using additives to improve early strength and 20% fly ash. Loss in strength was observed in cement mortars produced using glycol-based grinding aid. Increasing the dosage of chemical additive also led to loss in strength due to nonhomogeneous distribution of hydration products. As a result, grinding fly ash with clinker and the use of cement chemicals contribute to the cement sector in terms of sustainability. It is possible to produce cements with improved mechanical properties especially with the use of 20% fly ash.

Investigation of Usability Potential Geopolimer Concrete at Animal Barns Abstract

Onemli miktarda enerji ve ham madde tuketimine neden olan portland cimentosu CO2 emisyonunun yaklasik %7’sinden sorumludur. Cimento uretiminden kaynakli CO2 salinimi azaltilmasinda farkli yontemlerin arastirilmasi ya da CO2 salinimi daha az olan bir baglayici kullanilarak cimentoya alternatif malzeme kullanilmasini zorunlu kilmaktadir. Jeopolimer malzeme ise, beton uretiminde kullanilan portland cimentosunun (PC) aksine CO2 salinimi oldukca az, tuzlara ve asitlere dayanimi yuksek, sicaklik ve atese dayanimi yuksek olmasi gibi bircok farkli ozelligi sayesinde cimentoya alternatif malzeme olarak kullanim potansiyeli olan ve arastirilan bir malzemedir. Calisma kapsaminda hayvan barinaklarinda jeopolimer betonun etkileri arastirilmasi amaciyla jeopolimer malzemenin alkali aktivatoru olarak yuksek firin curufunun (YFC) %20’si oraninda seramik tozu (ST), sodyum silikat (Na2SiO4) ile sodyum hidrosit (NaOH) %60 – 40 oraninda aktivasyon cozeltisi ile kalsit agregasi kullanilarak numuneler hazirlanmistir. Boyutlari 4×4×16 cm numunelerde egilme ve basinc dayanimlari ile 25×25×285 mm numuneler uzerinde de buzulme oranlari belirlenmistir. Jeopolimer betonlarin hayvan barinaklarindaki durumlarinin belirlenmesi amaciyla numuneler %10’luk sulfirik asit (H2SO4) ve sulfat (SO4) solusyonunda bekletilmis ve numuneler 28, 56 ve 90. gunlerdeki dayanimlari karsilastirilmistir. Jeopolimer betonun hayvan barinaklarinda kullanilmasinin avantajlar saglayabilecegi gorulmustur.

Behavior of Mortar Samples with Waste Brick and Ceramic Under Freeze-Thaw Effect

Increasing number of industrial facilities and population concentration in particular regions along with overconsumption are main reasons of the increased environmental pollution. It is a necessity to preserve available resources and to keep the waste in control in order to achieve a sustainable development goal. In recent years, concepts of waste management, recycling and sustainability have gained importance with regards to the construction industry. Today, approximately 35 billion tons of concrete is produced worldwide and 80% of this amount consists of aggregated manufactured using natural resources. A significant environmental impact is the case even for the production of cement, a binding agent for concrete, which accounts for 1 ton CO2 emission in order to produce 1 ton of cement. The main subject of this study is the production of a sustainable construction material with the use of ceramic instead of both aggregate and cement. Clay is defined as a common natural material with fine-grains, with layers and a high water absorption capacity. Ceramic products are construction materials which can replace cement generally in the form of artificial puzzolana. The main subject of this study is the use of the waste obtained from ceramic plants which produces ceramic products in mortars. Taguchi L9 array design was used as part of this experimental study. Water-binder ratio was set to 0.50 in the preparation of the mixes and natural aggregates were used. Aggregates were then replaced by pieces ceramic and brick at a percentage between 20 and 60% while cement was replaced by ceramic and brick powder at a percentage between 10 and 30%. The mixes were then subjected to freeze and thaw tests at 30, 60 and 90 cycles in accordance with ASTM C 666 standard. Dynamic modulus and mechanical properties of the mortars subjected to f-t effect were then identified. When the results of the tests were examined, it was found that the compressive strength at 7th and 28th days were decreased with the increase of the volume of ceramic and brick powder used while it was found that the use of ceramic and brick powder did not have a significant effect on the compressive strength at the 90th day. The use of ceramic and brick aggregate led to favorable results in terms of freeze-thaw resistance. Especially the use of 10% ceramic [(whiteware) CA] and 20% other ceramic [(brick) BA] aggregate in mortars subjected to 90 f-t cycles increased the dynamic modulus while similar results were found for the use of 5% ceramic powder and 10% brick powder in mortars subjected to 90 days of f-t cycles. This study shows that waste material obtained from ceramic and bricks industry can be repurposed in the construction industry.

A Study on the Use of Advanced Nondestructive Testing Methods on Histroric Structures

Historic structures are social and cultural heritage for the land they are built on. To protect this heritage and to preserve it for the generations to come are among the most important responsibilities of nations. However numerous historical structures are found in Turkey, the awareness around nondestructive maintenance processes which will keep the identity of the structure intact is not developed as required. Historical structures require preservation, and necessary maintenance and reinforcement measures to be taken in order to survive damages arising from several reasons. Such work must be designed by multidisciplinary professionals and must be applied adhering to the original form of the structure. Among the limiting factors involved in an intervention to a structure is the knowledge on the strength and material properties of the structural elements used. Structural elements of a historical building must be subjected to measurements based on a number of assumptions made for parameters such as compressive strength, shear strength and elasticity modules. As a result of practices based on such assumptions, historical structures may face unnecessary repair and reinforcement processes. With the advancement made in technology now it is possible to obtain the necessary data from historical buildings without causing damage or causing minimal damage using nondestructive or semi-destructive test methods. Therefore, it is important and necessary to use and popularize the use of nondestructive testing methods for historical structures. This study investigates the following nondestructive testing methods and reports on the results obtained in a comparative manner: concrete rebound hammer method; flat-jack method; penetration resistance method; ultrasonic method; impact-echo method; and magnetic and electrical methods.

Prediction of Skid Resistance Value of Glass Fiber-Reinforced Tiling Materials

This research focuses on the use of adaptive artificial neural network system for evaluating the skid resistance value (British Pendulum Number; BPN) of the glass fiber-reinforced tiling materials. During the creation of the neural model, four main factors were considered: fiber, calcium carbonate content, sand blasting, and polishing properties of the specimens. The model was trained, tested, and compared with the on-site test results. As per the comparison of the outcomes of the study, the analysis and on-site test results showed that there is a great potential for the prediction of BPN of glass fiber-reinforced tiling materials by using developed neural system.

Cost Optimization of Mortars Containing Different Pigments and Their Freeze-Thaw Resistance Properties

Nowadays, it is common to use colored concrete or mortar in prefabricated concrete and reinforced concrete construction elements. Within the scope of this study, colored mortars were obtained with the addition of brown, yellow, black, and red pigments into the white cement. Those mixtures are examined for their compressive strength, unit weight, water absorption, and freeze-thaw resistance. Subsequent to comparison of these properties, a cost optimization has been conducted in order to compare pigment costs. The outcomes showed that the pore structure in architectural mortar applications plays an important role in terms of durability. And cost optimization results show that light colored minerals can be used instead of white cements.