13 research outputs found
Compressive strength and sulfate resistance of limestone and/or silica fume mortars
No full textIn this study, compressive strength and sulfate resistance of mortars containing silica fume and/or limestone in different replacement levels were examined. For this purpose, limestone was used as 5%, 20%, 35% and silica fume was used as 5%, 10%, 15% by weight of cement. Sixteen different blended cements were prepared containing limestone and/or silica fume in different ratios. Mortar mixtures were prepared using these 16 cements. Flow values and 2, 7, 28, 90, 180 day-compressive strengths of the mortar mixtures were determined. In addition, sulfate resistances of mortars were separately determined in sodium and magnesium sulfate solutions. Consequently, it was seen that negative effect of silica fume on workability of mortars and limestone on compressive strength of mortars can be compensated by using limestone and silica fume together. Simultaneous use of limestone and silica fume was showed to increase sulfate resistance of mortars. (C) 2011 Elsevier Ltd. All rights reserved
Usage of steel slag in concrete as fine and/or coarse aggregate
No full textIn this study, the use of steel slag as fine and/or coarse aggregate in concrete is investigated. For this purpose, 12 different concrete mixtures with different water/cement ratios of 0.40, 0.55 and 0.70 which include steel slag aggregate as fine and/or coarse aggregate are prepared. Compressive strength, split tensile strength, flexural strength, freeze-thaw resistance and water penetration depth of concrete mixtures containing steel slag aggregate are examined in comparison with concrete mixtures prepared by using crushed limestone aggregate. Eventually, concrete mixtures containing coarse steel slag show better performance than concrete mixtures containing limestone aggregate. Concrete mixtures containing fine steel slag show worse performance in comparison with concrete mixtures containing limestone aggregate
The effect of cylindrical specimen size on the compressive strength of concrete
No full textIn this study, the influence of size and capping type of cylindrical specimens on compressive strength of concrete is investigated. For this purpose, eight series of concrete mixtures were designed to have water/cement ratios of 37%, 42%, 47%, 48%, 55%, 62%, 71% and 77% (by volume). Three hundred and eighty-four cylindrical specimens having dimensions of 150/300 and 120/200 mm were casted. At the end of 28-day standard curing period, the uniaxial compressive strength of capped and uncapped specimens was determined. Cement, gypsum and sulphur are used as capping materials. The results of the experimental study reveal that the suitable average conversion factor (the ratio of compressive strength of 100/200 mm cylinder to 150/300 mm cylinder f(c100)/f(c150)) can be taken as 103%. Linear and nonlinear regression analyses were employed between f(c100) and f(c150). Linear and nonlinear regression analyses exhibited better performance. (c) 2006 Elsevier Ltd. All rights reserved
Usage of steel slag in concrete as fine and/or coarse aggregate
No full textIn this study, the use of steel slag as fine and/or coarse aggregate in concrete is investigated. For this purpose, 12 different concrete mixtures with different water/cement ratios of 0.40, 0.55 and 0.70 which include steel slag aggregate as fine and/or coarse aggregate are prepared. Compressive strength, split tensile strength, flexural strength, freeze-thaw resistance and water penetration depth of concrete mixtures containing steel slag aggregate are examined in comparison with concrete mixtures prepared by using crushed limestone aggregate. Eventually, concrete mixtures containing coarse steel slag show better performance than concrete mixtures containing limestone aggregate. Concrete mixtures containing fine steel slag show worse performance in comparison with concrete mixtures containing limestone aggregate.Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [107M607]This study was funded by the Scientific and Technological Research Council of Turkey (Project number: 107M607)
Investigation of sulfate resistance and alkali silica reaction in polymer-incorporating mortars
No full textBu çalışmada, polimer ilaveli harçların sülfat etkisine ve alkali silika reaksiyonuna karşı direnci incelenmiştir. Bu amaçla, bağlayıcı olarak normal portland çimentosu ve stiren-akrilik polimer emülsiyonu kullanılmıştır. Polimer ağırlıkça %0, 5, 10 ve 15 oranlarında çimento yerine ikame edilerek harç karışımları hazırlanmıştır. Hazırlanan harç örneklerinin 28 günlük basınç ve eğilme dayanımları, kılcal yolla su emme, porozite, birim ağırlık gibi özellikleri belirlenmiştir. Ayrıca harç karışımlarının ASTM C1012 standardına göre sülfat direnci, ASTM C1260 standardına göre alkali silis reaksiyonuna karşı direnci saptanmıştır. Polimer ilaveli harçlarda elde edilen sonuçlar kontrol harcı ile kıyaslamalı olarak değerlendirilmiştir.In this study, sulfate resistance and alkali silica reaction in mortars incorporating polymer were investigated. In this aim, normal portland cement and styrene-acrylic polymer emulsion were used. Mortar mixtures were prepared by replacing cement, with 0, 5, 10 and 15% polymer, by weight. 28-days compressive and flexural strength, water absorption and water sorptivity, porosity and unit weight of prepared mortar specimens were determined. Besides, sulfate resistance and alkali silica reaction resistance of prepared mortar mixtures were determined according to ASTM C1012 and ASTM C1260, respectively. Results obtained in polymeric mortar mixtures were comparatively evaluated with control mortar mixture
Effect of different curing conditions on flexural and compressive strength of fly ash mortars
No full textIn this study the effect of accelerated curing on the early flexural and compressive strengths of fly ash mortars were investigated. In the mortar mixtures CEM I 42.5 R type cement and C class C fly ash with different proportions were used. 40/40/160 mm prismatic specimens were prepared from these mortars. The mortar samples cured at 7 different curing conditions. Curing conditions are standard curing, 35 degrees C and 85 degrees C hot water curing. These curing conditions applied on specimens for different times. Flexural and compressive strengths were performed on the mortar specimens. Obtained test results were comparatively evaluated. The results of this study revealed that, early age strength gain under standard curing conditions due to fly ash inclusion can be compensated by accelerated curing
Effect of using substitution urea on fresh and hardened state properties of cementitious systems
No full textIt is well known that to ensure the durability of concrete throughout its service life, the search for alternative materials continues. The durability of concrete is enhanced by industrial urea. This study investigated the effect of urea on various fresh and hardened cementitious systems, focusing on durability performance. The durability of concrete is enhanced by industrial urea. This study investigated the effect of urea on various fresh and hardened cementitious systems, focusing on durability performance. Two series of paste and mortar mixtures were prepared for the research, and the replacement of water and cement was determined as 10%, 20% and 30% of the binder volume. The study investigated several properties of the produced cement paste and mortar mixes, including drying shrinkage, time-dependent flow, compressive strength, microstructural analysis, freeze-thaw resistance, carbonation depth, ultrasonic pulse velocity and water absorption. The results of the study showed that urea substitution increased the freeze-thaw resistance by up to 20% and reduced the drying shrinkage behaviour by up to 49%. The use of urea reduced the carbonation depth of mortar mixtures by 35%. It was also observed that the use of urea improved flowability
The effect of high temperature on the compressive strength of mortars
No full textIn this study, the effect of elevated temperature on the compressive strength of mortars containing fly ash, silica fume and pumice was investigated. Thirteen mortar mixtures were produced by replacing 0%, 5%, 10%, 15% and 20% of cement with a fly ash, silica fume and pumice. Totally, 3900 cube (50 x 50 x 50 mm) mortar specimens were prepared from these mortar mixtures and cured at 7, 28 and 90 days. After standard curing period. specimens were dried in a room temperature for 7 days and then exposed to temperature of 20, 150, 300, 450, 600 and 750 degrees C for 1 h in ceramic furnace. Afterwards, the compressive strengths of the specimens were determined. It was concluded that, compressive strengths of mortars containing pozzolan were less affected high temperature than that of control mortars. (C) 2012 Elsevier Ltd. All rights reserved
Prediction of mechanical and penetrability properties of cement-stabilized clay exposed to sulfate attack by use of soft computing methods
No full textSimilar to its effects on any type of cementitious composite, it is a well-known fact that sulfate attack has also a negative influence on engineering behavior of cement-stabilized soils. However, the level of degradation in engineering properties of the cement-stabilized soils still needs more scientific attention. in the light of this, a database including a total of 260 unconfined compression and chloride ion penetration tests on cement-stabilized kaolin specimens exposed to sulfate attack was constituted. the data include information about cement type (sulfate resistant-SR; normal portland (N) and pozzolanic-P), and its content (0, 5, 10 and 15%), sulfate type (sodium or magnesium sulfate) as well as its concentration (0.3, 0.5, 1%) and curing period (1, 7, 28 and 90 days). Using this database, linear and nonlinear regression analysis (RA), backpropagation neural networks and adaptive neuro-fuzzy inference techniques were employed to question whether these methods are capable of predicting unconfined compressive strength and chloride ion penetration of cement-stabilized clay exposed to sulfate attack. the results revealed that these methods have a great potential in modeling the strength and penetrability properties of cement-stabilized clays exposed to sulfate attack. While the performance of regression method is at an acceptable level, results show that adaptive neuro-fuzzy inference systems and backpropagation neural networks are superior in modeling.Ege University Science and Technology Centre-Technology Transfer Office (EBILTEM)Ege University [113M202, 2014-BIL-009]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113M202, 2014-BIL-009]The authors appreciate contributions of the Scientific and Technological Research Council of Turkey (TUBITAK) and Ege University Science and Technology Centre-Technology Transfer Office (EBILTEM) under grant numbers 113M202 and 2014-BIL-009, and the support provided by Cimenta Group, Denizli Cimento A.S. and Akcansa for providing cements used in the experimental part of this study
Comparison of fly ash, silica fume and metakaolin from mechanical properties and durability performance of mortar mixtures view point
No full textIn this study the effect of cement replacement with fly ash, silica fume and metakaolin on the compressive strength, dynamic elastic modulus, chloride-ion penetration, water absorption, water sorptivity, and freeze-thaw and sulfate resistance of the mortar mixtures were comparatively investigated. In addition, micro-structural investigation was performed on some selected mortar mixtures, and regression analysis was applied on the sulfate resistance test results. It was observed that, the presence of the mineral admixture and its type changed the ettringite morphology. Besides, only ball-ettringite and a special type of ettringite were observed in the silica fume- and metakaolin-bearing mixtures, respectively. The needle-like and ball-ettringite formation were found in the fly ash mixtures. In the control mixture the needle-like, ball-ettringite and massive ettringite were detected. Overall test results revealed that the performance of the mixtures was arranged in descending order as silica fume-, metakaolin-, fly ash-bearing mixtures and the control one. (C) 2014 Elsevier Ltd. All rights reserved
