the effect of taftan pozzolan on the compressive strength of concrete in the environmental conditions of oman sea (chabahar port)
cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issues, energy saving, the reduction of raw materials used for concrete production as well as technical advantages in many cases has culminated at increasing substitution of alternative materials or cement complements such as pozzolans in the worldwide production of concrete. furthermore natural and artificial pozzolans replaced with cement showed to have rather good performance in the concrete structures of erosive conditions. today a special attention has been drawn toward using pozzolan regarding its appropriate and good characteristics. according to the abundance of pozzolan mines around the taftan volcanic mountain located in sistan and balouchestan province and its vicinity to chabahar port (oman sea) the current thesis was titled by as "the effect of taftan pozzolan on compressive strength of concrete in the environmental conditioners of oman sea (chabahar port)" in this research, the effect of adding various percentages of taftan pozzolan as the partial alternative for cement into concrete mixture was experimentally studied and compared with the normal concrete samples without pozzolan. the experimental concrete mixes are set based on producing five concrete types, the normal concrete mix without any pozzolan admixture, samples consisting of 10, 15, 20 and 25 percent taftan’s pozzolan produced with 0.5, 0.4 and 0.35 water-cement ratios and cured in three type of pool: pool number one with oman sea water and samples fully cured, pool number two with oman sea water but sumples cured in the condition wet and dry successively and finally curing samples in the pool number three with the ordinary water used for constructional in chabahar city. for each concrete admixing sample, the compressive strength of the 7-day, 28-day and 90-day are tested. also to estimate the corrosion of steel rebars in the concrete mix, the steel reinforced samples are prepared and tested. the investigation results in this research show that the compressive strength of pozzolanic concrete increase in the long time. the growth percent of samples’ compressive strength from 7-day to 28-day is higher than that of from 28-day to 90-day .in the samples of all pools the compressive strength growth of 28-day to 90-day nearly increases when the portion of mixed pozzolan is raised. it indicates that, the chemical reaction of taftan’s pozzolan starts gradually over time and improves the compressive strength of concrete after 90 days, and adding the taftan’s pozzolan can improve the concrete admixture. also using the taftan’s pozzolan in the corresive conditions such as coastal area with sea tide improved the compressive strength of concrete samples
the washback effect of discretepoint vs. integrative tests on the retention of content in knowledge tests
در این پایان نامه تاثیر دو نوع تست جزیی نگر و کلی نگر بر به یادسپاری محتوا ارزیابی شده که نتایج نشان دهندهکارایی تستهای کلی نگر بیشتر از سایر آزمونها است15 صفحه اول
in the present study, the effect of e-64 at different concentrations (0.5, 1, 5 and 10 µm) added to (1) the ivm medium on oocyte nuclear maturation and developmental competence of ovine oocytes, and (2) to the ivc medium on embryonic development of ovine embryos were investigated.
the effect of learning strategies on the speaking ability of iranian students in the context of language institutes
the effect of learning strategies on the speaking ability of iranian students in the context of language institutes abstract language learning strategies are of the most important factors that help language learners to learn a foreign language and how they can deal with the four language skills specifically speaking skill effectively. acknowledging the great impact of learning strategies...
the effect of authentic listening materials on the listening proficiency of efl learners in the intermediate level
having conducted the experiment and analysed the data, the researcher computed the groups mean scores and variances for the test relating to the research question. as the final atep, a t-test was conodonted for the hypothesis. as noted earlier, the significance level was determined at .05 and .01 respectively. the observed t-value was higher than the critical t-value at. 5 and .01 levels. conse...15 صفحه اول
در این پژوهش به بررسی اثر افزایش ترافیک بر روی تعداد تصادفات پرداخته شده است. به این منظور 30 تقاطع در شهر تهران بطور تصادفی انتخاب گردید و تعداد تصادفات ماهیانه در این تقاطعات در طول سالهای 89-90 از سازمان کنترل ترافیک شهر تهران استخراج گردید و با استفاده از مدل داده های تابلویی و نرم افزار eviews مدل خطی و درجه دوم تخمین زده شد و در نهایت این نتیجه حاصل شد که تقاطعات پر ترافیک تر تعداد تصادفا...15 صفحه اول
چکیده یکی از مهمترین دغدغه های بزرگ جوامع بشری، از دیر باز تا کنون که ذهن پژوهشگران و متخصصان بهداشت روانی و اجتماعی و دولتها رابه خود مشغول داشته، مسأله ی بزهکاری می باشد. شناخت کامل پدیده ی بزهکاری و بزهکار، علل وعوامل سقوط یک انسان، چگونگی درمان وی و درنهایت پیشگیری ازبزهکاری ودریک کلام سالم سازی یک جامعه، رسالت عظیم، انسانی ومقدسی می باشد که با بررسی شخصیت مجرم یعنی[ انسانی که تحت شرای...15 صفحه اول