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Copyright of Current Research in Dental Sciences is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The durability of concrete or reinforced concrete structures subjected to aggressive environment depends mainly on the permeability of concrete. On the other hand there are various experimental methods that can be used to evaluate the permeability of concrete. Within the scope of the presented study, the permeability results of concretes produced with different cement types and also using fly ash as mineral additive, measured by different test methods, were investigated. Concrete composites with blended cements or fly ash concrete composites showed better permeability performance. Test results showed that chloride permeability, resistivity, water absorption and water penetration measurements can be used to reveal the permeability differences of the concretes at the same strength level. On the other hand air permeability and ultrasonic velocity tests were found to be insufficient to reveal the permeability differences of the concretes at the same strength level. [ABSTRACT FROM AUTHOR]

Copyright of Turkiye Klinikleri Journal of Dental Sciences is the property of Turkiye Klinikleri and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, physical and mechanical properties of non-structural composite panels used in buildings were determined experimentally. By evaluating the results obtained from the experimental study, the performances of these panels were revealed in terms of physical and mechanical properties. While evaluating the physical performance, its properties such as water absorption and expansion under moisture are taken into consideration. In terms of mechanical properties, four-point bending strengths, fracture energies, tensile strengths and modulus of elasticity values were obtained. The results of the water absorption and expansion tests were evaluated together and the relationships of these properties were revealed. Panels with optimum performance in terms of flexural strength and fracture energy have been determined. According to the results of the experimental study; While cellulose fiber reinforced cement matrix composite gives the highest strength values, cement-based textile reinforced composite panel exhibits the highest fracture energy. It has been concluded that glass fiber reinforced cement panels containing chopped glass fiber are the optimum solution in terms of flexural strength-fracture energy and expansion values. [ABSTRACT FROM AUTHOR]

With the increase in global warming, alternative solutions to traditional concrete are being inquired today to reduce dead loads of structures and improve their thermal insulation properties. Due to these needs, foam concrete with low unit weight and superior thermal properties comes to the fore. In this study, foam concretes with different unit weight were produced with different cements. In the scope of the study, composite cements consisting of CEM II, CEM II and CEM IV were used. 9 different mixtures were obtained with foam contents of 30, 60 and 90 kg/m3. 0-1 mm waste tires were used as aggregate in the production of foam concretes. As the foam content increased, the apparent porosity and water absorption values of concrete increased, while the unit weight values decreased. The unit weights of foam concretes range from 595-980 kg/m3. 28-day compressive strength ranges from 0.53-1.56 MPa. As the foam content of foam concretes increased, the depth of water penetration decreased. Water penetration depths of foam concrete are between 2.6-8.2 mm. As a result of two-way ANOVA analysis, the change in cement type does not affect the properties of foam concrete. But the change in foam content can directly affect the properties of foam concrete. The mechanical properties of foam concrete produced from CEM III type cement are higher than other cement types. As a result, it was determined that waste tires that are harmful to the environment and human health can be used in the production of foam concrete. It is estimated that foam concrete produced with waste rubber aggregate will show a closer thermal property than brick. [ABSTRACT FROM AUTHOR]

Digital image correlation (DIC) is a mathematically based non-contact deformation measurement technique. Engineered cementitious composites (ECC) exhibit steady state multiple-cracking behavior unlike conventional fiber reinforced composites. Analysis of this stable multiple cracking behavior is quite important in terms of evaluating the mechanical and durability performance of the composite. In this study, DIC's application areas on deformation measurements of engineering materials are presented with a detailed literature review. Studies on the analysis of the multiple cracking behavior of ECC have been researched and the availability of the DIC method experimentally investigated for this purpose. In this context, dog-bone shaped tensile specimens were produced by using high tenacity polypropylene fibers (HTPP-ECC). The deformations of the composites under tensile loading were recorded with 4 conventional deformation gauges (LVDT-Linear variable differential transformer) and a DIC based camera system. The usability of DIC technique in the investigation of the multiple cracking behavior of composites was investigated by comparing the data obtained by LVDT and DIC methods. In conclusion, DIC has close results with LVDTs in terms of deformation measurement in ECCs and has superiority than traditional methods with the advantage of crack analysis. [ABSTRACT FROM AUTHOR]

In our country which is extremely rich in natural puzzulanas, multiple profits are gained. Some of these profits are energy saving in the production of cement and the decrease of environmental pollution by this way. By decreasing the clinker and using puzzulana admixture material instead, the CO2 gas occurring during the production of cement can be decreased and energy saving is provided. In this study, the effect of adding the zeolite admixture at %0, %5, %10, %15 and %20 rates into Portland cement on cement grout qualities has been examined. The physical and chemical analyses of cement grout samples with zeolite addition, their resistances to pressure for 2, 7 and 28 days and SEM-EDS images have been examined. The best pressure resistance is obtained from cement grouts with %10 zeolite addition. [ABSTRACT FROM AUTHOR]

Most frequently preferred construction system in our nation is the reinforced concrete construction system in which concrete and construction steel are used together. Because the construction steel is manufactured in factories, it generally provides the required tensile strength specifications. However, concrete is produced under construction site conditions. Types and features of the ingredients vary depending on climatic conditions, technology in the use and knowledge level of labors. The ingredient, which has the most significant effect on features of a concrete, is aggregate accounting for 60-70% of its volume. The more physical structure of a concrete is dense, the higher its compactness and pressure strength are. The basic factor determining quantities of the ingredients in a concrete's composition, and its compactness and porosity is granulometric features of the aggregate creating its carrying framework. Quantity of gaps between grains of an aggregate, in other words porosity, may be minimized by making mixture calculations according to the standards to produce a concrete having maximum compactness. As the quantity of gaps between grains decreases, quantity of cement and quantity of water used in making cement paste decrease. The object of this study is to determine effect of the aggregate granulometry on theoretical material quantities in a concrete composition and also on compactness and porosity values of the concrete. [ABSTRACT FROM AUTHOR]

Improvements in concrete technology enabled engineers to produce special concretes with high strengths. However, as known high strength concrete exhibits a very brittle behavior. Many researchers have tried to change this brittle failure mode to a ductile type failure by adding various types of fibers in to the concrete. Consequently, different types of concrete with fibers were developed such as Fiber Reinforced Cementitious Composites (FRCC), Fiber Reinforced Concrete (FRC), Ductile Fiber Reinforced Cementitious Composites (DFRCC), High Performance Fiber Reinforced Cementitious Composites (HPFRCC) etc. Many researches on this topic have showed that fibers increased the ductility and energy dissipation capacity of the concrete members. In this research; the main goal is to develop a material that can be used to improve the behavior of reinforced concrete members built with low-strength concrete (f'c≈10 MPa, in which f'c is the compressive strength of the concrete) under seismic loads. HPFRCC may be used for this purpose. The main idea is to produce precast thin panels made of HPFRCC and retrofitting reinforced concrete members by attaching these panels to the surface of the reinforced concrete members. It is clear that as the mechanical properties of the HPFRCC improve, the effectiveness of HPFRCC panels in retrofitting will also increase. In order to investigate the mechanical characteristics of the HPFRCC, two series of experimental studies were carried out. The first series of tests included compression tests of 27 standard cylinder specimens and tension tests of 54 standard splitting disc specimens. For compression tests nine sets and for each set three identical cylinder specimens were produced. For tension tests six standard splitting disc specimens were produced for each of nine sets. The diameter of cylinder is 150 mm and height is 300 mm. The diameter and height of the standard splitting discs are 150 and 60 mm, respectively. In the tests of the first series, the testing parameters included hot water curing, decomposition of steel fibers before adding them into mixture, corrosion and the amount of steel fibers. Second series of tests included flexural tests of beams with dimensions of 100x100x500 mm. The only parameter in beam tests is the amount of steel fibers. Three different mixtures and for each fixture there identical beams were produced. Compression tests of standard cylinder specimens were carried out either under static monotonic or cyclic axial compression loads by using Amsler machine with 5000 kN loading capacity. Two linear displacement transducers were used to measure axial deformations. To determine the elastic modulus, the specimens were subjected to one loading and unloading cycle in the linear range of the stressstrain curve before the full test and then elastic modulus was obtained from the slope of the linear best-fit line. During loading and unloading cycle axial deformations were measured both in the full length (≈300 mm) and in 150 mm at midheight of the specimens. For the tests of standard disc specimens a 1000 kN capacity Amsler machine was used. For the beam tests 100 kN capacity Instron 5500R machine was used. Fracture energy, bending strength and toughness of the specimens were obtained from load-displacement curves. Three point loading tests were carried out for beams and loading rates were 0.05 mm/minute and 0.1 mm/minute for the ascending and descending branch of load-displacement curves, respectively.… [ABSTRACT FROM AUTHOR]