In this study, optimization of durability properties of the concretes was performed by using Taguchi method and Anova analysis. The durability performance of the concretes was evaluated using measurements of rapid chloride ion permeability, freezing-thawing resistance and sorptivity tests. The degree of freezing-thawing resistance was assessed the change of weight, ultrasonic pulse velocity (UPV) and flexural strength after 300 cycles. The use of fly ash improved the rapid chloride ion permeability and sorptivity of concrete. The best resistance to chloride ion permeability was obtained from a combination of type of class C fly ash content of 102 kg/m(3) with PC content of 332 kg/m(3). There was a remarkable reduction in the UPV after the specimens are subjected to freezing-thawing cycles. The amounts of flexural strength loss have been measured in the range of 6.70 - 29.83%. The use of type of class C fly ash positively affected freezing-thawing resistance of concrete. The Anova analysis indicated that the cement dosage has an utmost importance on the sorptivity level, chloride ion permeability and ultrasonic pulse velocity loss. Furthermore, the fly ash percentage has an utmost importance on the weight loss and flexural strength loss.

This paper presents the modeling of an experimental investigation carried out to evaluate some mechanical and durability properties of concrete mixtures in which cement was partially replaced with Class C and Class F fly ash. A total of 39 mixtures with different mix designs were prepared. After compressive strength testing, the mixtures containing Class F and Class C fly ashes which had similar compressive strength values to control mixtures at 28 d for each series were used for sulfate resistance tests. The degree of sulfate attack was evaluated using expansion and weight loss. The test results indicated that Class C fly ash showed higher compressive strength than Class F fly ash. Moreover, the addition of fly ash significantly increased the resistance to sulfate attack when each amount of fly ash addition regardless of fly ash types was employed. In this paper, the Artificial Neural Network (ANNs) techniques were used to model the relative change in the weight and length of the concrete exposed to sulfate. The best algorithm for length changes of concrete exposed to sulfate is BFGS quasi-Newton backpropagation algorithm while the best algorithm for weight changes of concrete exposed to sulfate is the Levenberg-Marquardt backpropagation algorithm.

In engineering applications when materials start sliding against each other the problem of friction and wear appears.In the case of polymers the friction between them can be attributed to two main mechanisms: deformation and adhesion.One of the important application fields for polymers is the medical engineering.In this field, the UHMWPE polymer is one of the important candidant polymer material.In this investigation, the friction and wear performance of GUR 1020 medical grade UHMWPE polymer under dry sliding conditions is evaluated.The sliding experiments were carried out on a pin-on-AISI stainless steel disc arrangement.Wear tests were carried out under room temperature, 50, 100and 150N load values and at 0.50, 1.0 and 2.0m/s sliding speed conditions.The results show that the coefficient of friction for GUR 1020 medical grade UHMWPE polymer is significantly influenced by applied load, sliding speed values.Furthermore, the coefficient of friction and specific wear rate increases with the increase in applied load and sliding speed values.The specific wear rate values for GUR 1020 medical grade UHMWPE polymer under dry condition is at the order of 8x10 -14 m 2 /N.The friction coefficients vary between 0.12 and 0.20.Finally, the wear mechanism includes abrasive and adhesive processes.

Many researchers agree that the ASR expansion values that are made on mineral and chemical additive concrete and mortar samples give more rational results.

This study was carried out on the effect of NaCl and MgSO4 solutions on the mechanical and physical properties of mortars with and without fly ash. Experiments were conducted on the standard mortars and mortars with fly ash in the replacement ratio of 20–50%. Class F Çayırhan, fly ash and CEM I 42.5N cement were used. NaCl and MgSO4 exposure of mortars were initiated after 28days standard water curing. Tests of 28, 56, 90th days were conducted on flexural strength, compressive strength, unit weight, volumetric water absorption, capillary water absorption, resonance frequency and ultrasound velocity. Nine specimens from each series at the size of 40×40×160mm were kept in NaCl and MgSO4 at the same concentrations of 40,000mg/l. At the end of destructive and nondestructive tests, it is seen that specimens kept in the solution of NaCl had less compressive and flexural strength than the stored one in the solution of MgSO4. The solution of NaCl damaged the specimens more than the solution of MgSO4 did.

This paper presents the results of an experimental investigation carried out to evaluate compressive strength and sulfate resistance properties of concrete mixtures in which Turkish Class C and Class F fly ashes were partially replaced with cement. A total of 39 mixtures with different mix designs were prepared. Compressive strength tests were carried out and the mixtures with similar compressive strength values were used for sulfate resistance tests. The degree of sulfate attack was evaluated using expansion and weight loss tests. Compression test results indicate that the concrete mixture with Class C fly ash showed higher compressive strength than that with Class F fly ash. Moreover, regardless the fly ash type, the addition of fly ash significantly increased the resistance to sulfate attack. (C) 2012 Elsevier Ltd. All rights reserved.

Large volumes of earthen materials are used in construction each year in Turkey and elsewhere. The wastes generated from these materials can be utilised in various applications including road subbase filling materials. In this study, three different types of wastes namely fly ash, marble dust and waste sand are used. These wastes were mixed with natural soils as a potential alternative filling materials in the road subbase. Two types of natural soils were replaced with 0%, 5%, 10%, 15%, 20% of fly ash, marble dust and waste sand. Standard compaction, permeability and saturated California Bearing Ratio (CBR) tests, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analysis were performed on two types of natural soils, containing three industrial waste types in different ratios. The study indicates that the fly ash, marble dust and waste sand are fairly good additive materials in road subbase fill and reaction substantially improves their CBR, swelling ratio and water conductivity. It was found that a clear optimum replacement level of 15% for all of these by products for medium and low plasticity type of soils.

This paper presents experimental study on the properties of self-compacting concrete (SCC). Portland cement (PC) was replaced with fly ash (FA), granulated blast furnace slag (GBFS), limestone powder (LP), basalt powder (BP) and marble powder (MP) in various proportioning rates. The influence of mineral admixtures on the workability, compressive strength, ultrasonic pulse velocity, density and sulphate resistance of SCC was investigated. Sulphate resistance tests involved immersion in 10% magnesium sulphate and 10% sodium sulphate solutions for a period of 400days. The degree of sulphate attack was evaluated using visual examination and reduction in compressive strength. The test results showed that among the mineral admixtures used, FA and GBFS significantly increased the workability and compressive strength of SCC mixtures. Replacing 25% of PC with FA resulted in a strength of more than 105MPa at 400days. Moreover, the presence of mineral admixtures had a beneficial effect on the strength loss due to sodium and magnesium sulphate attack. On the other hand, the best resistance to sodium and magnesium sulphate attacks was obtained from a combination of 40% GBFS with 60% PC.

The white cement, which has been used more widely in aesthetic and decorative applications in Turkey and the use of white cement has not widely common yet in constructional applications. In this study white cement, white calcareous aggregate and marble powder are used and produced white concrete. Furthermore, the effect of curing conditions was investigated on the compressive strength behavior of structural elements. For this reason, the performance properties of white concrete with various cement contents in the range of 250-650 kg/m3 were examined experimentally by keeping chemical admixture ratio constantly. The mixtures were produced in ten different proportions with and without chemical admixtures. The concrete mixtures which were prepared and cured in three different curing conditions. Some of the specimens were placed in water at 20 ± 2 oC and some of them were kept in laboratory environment without placing in water (20 ± 2 oC and % 68 RH) and the rest of the specimens were kept in nylon cover. In hardened concrete testing, compressive strength test was performed at 7, 28 and 90 days for white concrete specimens. Based on these concrete designs, it can be concluded that by the use of white cement between 250 and 650 kg/m3 it is possible to produce white concrete according to the ready-mixed concrete standard. According to test results, the specimens which were kept in water and prepared with chemical admixtures were performed better performance than the specimens were kept in air and nylon cover and produced without chemical admixtures.

Fly ashes are obtained from thermal power plants and they are pozzolanic materials, which can act as partial replacement material for both portland cement and fine aggregate. With their economical advantages and potential for improving fresh and hardened concrete performance, they have some benefits for using in concrete industry. In this study, the objective was to find the efficiency factors of Turkish C and F-type fly ashes and to compare their properties. Three different cement dosages were used (260, 320, 400kg/m3), two different ratios (10% and 17%) of cement reduced from the control concretes and three different ratios (depending on cement reduction ratio) of fly ash were added into the mixtures. At the ages of 28 and 90days, compressive strength, modulus of elasticity and ultrasound velocity tests were carried out. From the compressive strength results, the k efficiency factors of C and F-type fly ashes were obtained. As a result, it is seen that efficiency factors of the concrete produced by the replacement of F and C type fly ashes with cement increase with the increase in cement dosage and concrete age.

In this study, mixing rates, fiber content and pre-setting pressure of reactive powder concrete (RPC) were examined. Mixing ratios were determined by different mixing techniques in literature using material characteristics via computer software. The samples were prepared according to these mixing ratios. The fresh (plastic) concrete samples were filled in a specified mould. Six different (0, 5, 10, 15, 20, 25MPa) pre-setting pressure were applied. It is observed that application of pre-setting pressure increased compressive strength of the samples about twice.

The white cement, which has been used more widely in aesthetic and decorative applications in Turkey and the use of white cement has not widely common yet in constructional applications. In this study white cement, white calcareous aggregate and marble powder are used and produced white concrete. Furthermore, the effect of curing conditions was investigated on the compressive strength behavior of structural elements. For this reason, the performance properties of white concrete with various cement contents in the range of 250-650 kg/m3 were examined experimentally by keeping chemical admixture ratio constantly. The mixtures were produced in ten different proportions with and without chemical admixtures. The concrete mixtures which were prepared and cured in three different curing conditions. Some of the specimens were placed in water at 20 ± 2 oC and some of them were kept in laboratory environment without placing in water (20 ± 2 oC and % 68 RH) and the rest of the specimens were kept in nylon cover. In hardened concrete testing, compressive strength test was performed at 7, 28 and 90 days for white concrete specimens. Based on these concrete designs, it can be concluded that by the use of white cement between 250 and 650 kg/m3 it is possible to produce white concrete according to the ready-mixed concrete standard. According to test results, the specimens which were kept in water and prepared with chemical admixtures were performed better performance than the specimens were kept in air and nylon cover and produced without chemical admixtures.

The friction and wear properties of pure poly-tetra-fluoro-ethylene (PTFE), 35% carbon filled poly-tetra-fluoro-ethylene (PTFE+35%C), and 17% glass fiber-reinforced polytetra- fluoro-ethylene (PTFE+17% GFR) sliding against stainless steel under dry sliding conditions were studied by using a pin-on-disc tribometer. The effect of applied pressure and sliding speed on tribological properties of the polymer-stainless steel combination under dry sliding conditions was investigated. Tests were carried out at sliding speeds of 0.32, 0.64, 0.96, 1.0, 1.5, and 2.0 m/s and under applied pressures of 0.17, 0.34, 0.68, 1.02, 1.76, 3.53, 5.30, and 7.07 MPa. Optical microscopy was utilized to examine the worn surfaces of pure PTFE and it's composite. The results indicated that, for pure PTFE, carbon-filled PTFE and glass fiber-reinforced PTFE composites are used in this investigation; the friction coefficient decreases with the increase in applied load values. The maximum reduction in wear rate was obtained by glass fiber-reinforced PTFE composite. The specific wear rate for pure PTFE, carbon filled PTFE composite, and glass fiber-reinforced PTFE composite were in the order of 10(-13), 10(-14), and 10(-15) m(2)/N, respectively. The wear mechanism include adhesive and abrasive processes.

In this study, the tribological performance of pure polyetheretherketone (PEEK) and 30wt% fibre glass (GFR) reinforced PEEK composite were studied at dry sliding and water lubricated conditions. Wear tests were carried out with configuration of a polymer pin on a rotating AISI D2 disc. Test conditions were atmospheric conditions, 1.77, 3.54, 5.30MPa pressures and 0.80, 1.60m/s sliding speeds. The results show that the coefficient of friction and specific wear rates for pure PEEK and PEEK+30wt% GFR composite slightly in increase with the increase in applied pressure values. On the other hand the coefficient of friction is in decrease while the specific wear is in increase with the increase in sliding speed values. Moreover, for the range of pressure and sliding speed of this study, the coefficient of friction and specific wear rates using water lubricant registered lower values than that of the dry condition. The influence of GFR fibre on the coefficient of friction and wear of the composite is more pronounced at dry wear test condition. Finally the specific wear rates for pure PEEK and PEEK+30wt% GFR under water lubricated condition were in the order of 10−15m2/N while under dry sliding condition this value is in the order of 10−14m2/N.

In this research, the effects of filler (rock-dust) usage on high strength concrete have been investigated through lab experiments and some results have been obtained. The experiments involved three series of concrete with different cement proportions of 375 kg/m3, 400 kg/m3, and 425 kg/m3. For each series of concrete, three different groups of samples have been prepared, the first one being the reference concrete which contained 0% chemical admixture and 0% filler, the second one contained 1.5% chemical admixture and 0% filler and finally the last group contained 1.5% chemical admixture and 5% filler to the weight of cement used. The chemical admixture used was a type of Super plasticizer with a brand name of “DARACEM 190”, and the cement used was Ordinary Portland Cement of target compressive strength 42.5 N/mm2, obtained from Nuh Cement Plant. For each batch, Slump Tests and Unit Weight Tests were performed. For each stage and group, two 15 cm cubic samples have been tested for Compressive Strength after being cured in water at 20 ± 2 °C for ages of 3 days, 7 days, 28 and 60 days. The total number of samples was 72. As a result, filler usage was found to reduce the porosity of Concrete, increase the Unit Weight of Concrete, increase the need for water and improve the Compressive Strength Properties of Concrete.

In this research, the effects of filler (rock-dust) usage on high strength concrete have been investigated through lab experiments and some results have been obtained. The experiments involved three series of concrete with different cement proportions of 375 kg/m(3), 400 kg/m(3), and 425 kg/M-3. For each series of concrete, three different groups of samples have been prepared, the first one being the reference concrete which contained 0% chemical admixture and 0% filler, the second one contained 1.5% chemical admixture and 0% filler and finally the last group contained 1.5% chemical admixture and 5% filler to the weight of cement used. The chemical admixture used was a type of Super plasticizer with a brand name of "DARACEM 190", and the cement used was Ordinary Portland Cement of target compressive strength 42.5 N/mm(2). obtained from Nuh Cement Plant. For each batch, Slump Tests and Unit Weight Tests were performed. For each stage and group, two 15 cm cubic samples have been tested for Compressive Strength after being cured in water at 20 +/- 2 degrees C for ages of 3 days, 7 days, 28 and 60 days. The total number of samples was 72. As a result, filler usage was found to reduce the porosity of Concrete, increase the Unit Weight of Concrete, increase the need For water and improve the Compressive Strength Properties of Concrete.

In this research, the effects of zeolite, coal bottom ash and fly ash as Portland cement replacement materials on the properties of cement are investigated through three different combinations of tests. These materials are substituted for Portland cement in different proportions, and physical properties such as setting time, volume expansion, compressive strength and water consistency of the mortar are determined. Then, these physical properties are compared with those of PC 42.5. The results showed that replacement materials have some effects on the mechanical properties of the cement. The inclusion of zeolite up to the level of 15% resulted in an increase in compressive strength at early ages, but resulted in a decrease in compressive strength when used in combination with fly ash. Also, setting time was decreased when zeolite was substituted. The results obtained were compared with Turkish Standards (TS), and it was found that they are above the minimum requirements.

The Marmara earthquake, occurred on August 17, 1999 at 0 3.02 am (local time), was one of the biggest disasters in Turkey. The magnitude was M-w =7.4 on the Richter scale and associated with faulting over a length of 120 km. It was resulted in nearly 2 0.000 deaths, over 40.000 injuries, and destroyed about 80.000 buildings. This could be concluded owing to the bad soil conditions with quality of materials and workmanship used in the construction.This study was conducted primarily to determine the compressive strength of concrete core samples evaluated from the totally collapsed or heavily damaged structures in Adapazari, which was the most effected city in the region. The specimens were tested using the universal testing machine according to Turkish Standards (TS) and the evaluated results were compared with TS. The outcomes confirmed that the totally collapsed or heavily damaged structures were not built in proper materials condition. More than 65% of the concrete specimens of the compressive strength found to be less than C16 which is under the minimum values according to the Turkish building code. Therefore, it is concluded that one of the main reason of the collapsed or heavily damaged building was the quality of the material, especially concrete, used in the construction of buildings.

Turkiye'de Cimento Sanayiinin baslangici ve gelisimi belirtilen bu makalede cimento sanayii'nin bu gu nlere nasil geldigini, ne kadar gelistigini, su andaki mevcut durumunun nedenleri aci klanmakta; Turkiye'deki cimento turleri, yil yil artis nllktarlan ve standartlarda aranan ozellikler anlatilinaktadir