پديد آورندگان :
كابوسي، كامي دانشگاه آزاد اسلامي - گروه مهندسي آب، گرگان , فدوي، مهران دانشگاه آزاد اسلامي - گروه مهندسي آب، گرگان , ستايش، احسان دانشگاه آزاد اسلامي - گروه مهندسي آب، گرگان
كليدواژه :
آب نامتعارف , سن بتن , طرح اختلاط , عيار سيمان
چكيده فارسي :
به دليل مجاورت به دريا، شرايط زمينشناسي و ويژگيهاي هيدروژئولوژي مناطق شمالي و غربي استان گلستان، آب زيرزميني در اين منطقه بسيار شور است. از سوي ديگر، به دليل عدم دسترسي به آب سطحي با كيفيت مناسب در اغلب ماههاي سال، انجام فعاليتهاي عمراني و ساختماني در اين منطقه همواره با چالشهايي همراه است. بر اين اساس، پژوهش حاضر با هدف بررسي 120 تيمار دربرگيرنده سه سطح كيفيت آب (شامل آب شهري، شورآبه زيرزميني و تركيب آب شهري و شورآبه زيرزميني با نسبت برابر)، چهار سطح زئوليت (شامل كاربرد 0، 10، 20 و 30 درصد زئوليت به جاي سيمان در طرح اختلاط)، دو سطح مصالح سيماني (شامل 250 و 350 كيلوگرم بر مترمكعب) و پنج سن اندازهگيري مقاومت فشاري (3، 7، 21، 56 و 90 روز) در سه تكرار صورت گرفت. نظر به تنوع قابل ملاحظه تيمارهاي آزمايش در اين پژوهش و با توجه به عدم تجزيه و تحليلهاي آماري در پژوهشهاي قبلي، نتايج پژوهش حاضر در قالب طرح كاملاً تصادفي به صورت آزمايش فاكتوريل تحت آزمونهاي تجزيه واريانس (ANOVA) و مقايسه ميانگينها (LSD) قرار گرفت. نتايج نشان داد كه امكان استفاده از شورآبه زيرزميني و زئوليت در طرح اختلاط بتن به ويژه در عيار سيمان 350 كيلوگرم بر مترمكعب بدون آن كه موجب كاهش معنيدار مقاومت فشاري بتن گردد، و حتي اين ويژگي را در برخي شرايط به طور معنيداري افزايش دهد، وجود دارد. با اين حال، با توجه به وجود برهمكنش سهگانه اين عوامل كه به معناي اثرات متفاوت نوع آب و درصد زئوليت در عيارهاي مختلف سيمان است، انتخاب بهترين سطح كاربرد زئوليت و نوع آب با توجه به عيار سيمان مورد نظر بايد بر اساس آزمون طرح اختلاط در كارگاه به دست آيد.
چكيده لاتين :
Global water scarcity and air pollution by greenhouse gases have amplified the need to use of unconventional water and environmental friendly materials in the concrete industry. Because of its proximity to the Caspian sea, the geological conditions and hydrogeological characteristics of the northern and western regions of Golestan province, groundwater in this area is very salty. On the other hand, due to lack of access to good quality surface water in most of the months, civil and construction activities in this area are always challenging. Accordingly, the present study was conducted to investigate 120 treatments (including three levels of water quality including tap water, briny grounwater and mixture of equal ratio of tap water and briny grounwater), four levels of zeolite (including 0, 10, 20 and 30 percent of zeolite application instead of cement in the concrete mix design), two levels of cement content (including 250 and 350 kg.m-3) and five curing ages (including 3, 7, 21, 56 and 90 days) in three replications. Considering the considerable types of the experimental treatments in this study and in respect to the lack of statistical analysis in previous studies, the results of this study were analyzed based on a completely randomized design with factorial experiment using analysis of variance (ANOVA) and means comparison (LSD) tests. Averagely, use of briny groundwater resulted insignificant increase in the compressive strength of concrete specimens compared to tap water, while combined water significantly decreased this property, but this reduction was within permissible range 10 percent based on national and international standards. Also, replacement of 10, 20 and 30 percent of cement by zeolite compared to non-zeolite treatment significantly reduced the compressive strength of concrete specimens by 9.9, 9.5 and 23.1 percent, respectively, but the difference between replacement level 10 and 20 percent was not significant. However, Concurrent use of briny groundwater and zeolite up to 20% can be recommended without significantly reducing the compressive strength of concrete. In the cement content of 250 kg.m3, the difference between tap water and combined water treatments was not significant, but the use of briny groundwater resulted significance increase in compressive strength of concrete pieces by 22.8 and 21.8 percent compared to tap water and combined water, respectively. In contrast, in the cement content of 350 kg.m-3, the highest compressive strength was obtained in samples made with tap water, briny groundwater and combined water, respectively, and the differences between them were statistically significant. The results showed that due to two- and three-way interaction of these three factors on compressive strength of cement pieces, which means different effects of water quality and application percent of zeolite on different content of cement, the choice of the best application level of zeolite and water type according to the cement content should be selected based on the mix design test in building site. However, using of briny grounwater and zeolite in the concrete mix design, especially in cement content of 350 kg.m-3, without significantly reducing the compressive strength of concrete and even significantly increase of this property in some treatments, is recommended.
