تاثير پوزولان و فيلر بر نتايج فاز خميري، مقاومت و رفتار محصورشده‌ي بتن خودتراكم حاوي نانو مقاومت بالا

Effect Of Pozzolan And Filler On Plastic Phase, Stenght And Confined Characteristic Of Nano High Strength Self Compacting Concrete

به‌دليل جايگاه ويژه‌ي بتن در صنعت ساخت و ساز، امروزه توليد نسل‌هاي جديد بتن، بتن خودتراكم حاوي نانو (نانو بتن خودتراكم)، مواد افزودني با كارايي‌هاي مختلف مطرح است. نانو بتن خودتراكم مقاومت بالا (NHSSCC) به عنوان نمونه‌ي بارز بتن‌هاي نسل جديد در اين تحقيق مورد مطالعه قرار گرفته است. بدين منظور، ابتدا نانو بتن خودتراكم مقاومت بالا همراه با ويژگي هاي فاز خميري مطلوب آن طراحي و ساخته شد و سپس تاثير پوزولان بر مقاومت فشاري تك محوره، ميزان جذب آب و تعيين مقاومت بتن در شرايط محصورشده با انجام آزمايش سه محوره و رسم دواير مور تعيين و در اين تحقيق گزارش شده است. نتايج حاكي از تاثير مثبت استفاده از پوزولان در اين نوع بتن‌هاست.

Based on significant role of concrete in construction industry, this material is known as one of the most common used substance for researchers, this special consideration leads to invention of new generation concrete and various admixtures with different applications. Self compacting concrete (SCC) is one of these new combinations which was offered at 1986 due to nonqualified conventional concrete (vibrated concrete) in 1980 decade. Self compacting concrete has well application in construction procedure by passing freely around and through reinforcement and covers all the spaces inside the framework and can be compacted by its own weight without need of any vibration. Lower time and lower cost of construction, lower sound pollution and high homogeneous concrete are some advantages of SCC. In more recent years the tendency to use high strength self compacting concrete, HSSCC are increased rapidly and also the use of nano particles in developing materials has gained enormous attention due to their extreme fine size. Nono technology has made an outstanding progress in various fields and materials and its usage is going on to increase. Materials smaller than 100 nanometer are involved in this technology and their application in HSSCC needs to be investigated. Mechanical properties (compressive and tensile strength, modules of elasticity, shrinkage and creeping) and durability (durability against freezing and thawing cycles, sulfate attack and carbonation) of concrete are seems to be dependent on nano behavior rather tan the micro behavior, and improvement of nano may leads to progress in concrete quality much more than before. In this investigation, by trial and error procedure, different mix design of nano HSSCC were caste and tested to reach a so called standard nano HSSCC in fresh matrix phase (i.e., the rheology of fresh nano HSSCC such as; values of slump flow diameter, T50, L-box, V-funnel, J-ring, and column segregation). Based on the results obtained, the two best so–called standard mix designs were selected for further investigations. The effect of two types of fillers, lime stone powder and pozzolan on parameters like uni axial compressive strength of concrete, ranged of absorbed water and concrete strength determination on confined situation which is performed by the triaxial test. Failure analysis of triaxial test stresses is performed and normal main stress and shear stress along with Mohr’s circles are achieved. The results are indicated that, natural and artificial using of pozzolan materials in nano HSSCC causes increase in strength at older ages and concrete durability.