مطالعه آزمايشگاهي تاثير مواد آب بند كننده رايج بر مقاومت بتن و بتن اليافي فولادي، پلي پروپيلن و شيشه اي

Effect of Waterproof Materials on Concrete Strength and Steel, Polypropylene and Glass Fibers Concrete

در اين تحقيق به بررسي آزمايشگاهي تاثير مواد آب بند كننده بر مقاومت بتن و بتن اليافي پرداخته شده است. بدين منظور براي بتن بدون الياف و نيز بتن اليافي با الياف فولادي، پلي پروپيلين و شيشه، پارامتر هاي مقاومتي فشاري و خمشي با اضافه نمودن مواد آب بند رايج با درصدهاي مختلف مورد بررسي قرار گرفته است. آزمايشات مقاومت فشاري و خمشي در سنين 7، 28 و90 روزه بر روي آزمونه هاي منشوري انجام گرفته است. آزمايشات در 34 طرح اختلاط به تعداد 408 نمونه و با تكرار صورت گرفت. در ساخت بتن اليافي از تركيب مواد آب بند كننده شامل ماده آب بند كننده پودري با خاصيت اسيدي خنثي و مايع با خصوصيت قليايي و الياف شامل فولادي، پلي پروپيلن و شيشه اي استفاده شده است. نتايج آزمايشات بيانگر اين است كه حضور مواد آب بند كننده ي با خاصيت اسيدي خنثي در بتن بدون الياف باعث افزايش مقاومت فشاري و خمشي بتن مي گردد. همچنين از مهمترين نتايج اين تحقيق اين است كه افزودن 1 درصد ماده آب بند كننده bc40 (با خاصيت اسيدي خنثي) به بتن اليافي شكل گرفته با 2 درصد الياف فولادي باعث افزايش 27% مقاومت فشاري نسبت به نمونه شاهد با اليافي فولادي و بدون ماده آب بند در مقاومت 90 روزه شده است در حاليكه در مقاومت خمشي اين تركيب تغيير محسوسي ملاحظه نگرديده است. بحث و تجزيه و تحليل پيرامون نتايج در حالات مختلف از ديگر نكات مطرح شده در اين مقاله مي باشد.

Concrete is the most widely used building material. In Iran, the consumption of chemical additive materials has been significantly more than the average consumption in the world. This is true especially in the case of ready-mixed concrete industry which is the major producer and contributor of concrete in the country. Ready-mixed concrete industry is among the highest potential sections that must pay attention to the valuable characteristics of chemical additives. Therefore, it is essential to develop the knowledge and technology of chemical additive materials over the past decades in Iran. One of the important cases about concrete structures, especially structures permanently or non-permanently located in the vicinity of water and chemicals, is blocked effect against leakage, influence, pressure or water containing chemicals attack. In this context, a type of concrete should be used that is commonly known as “waterproof”. Also, to prevent cracking, high ductility, supernatural strength and energy absorption capability fiber can be used in concrete or which many application instances can be found. To date, it has become clear that different types of fiber can increase strain capacity, resistance to impact, energy absorption, abrasion resistance and tensile strength of concrete. In this research, the influence of the strength of regular concrete and fiber concrete sealing substances has been investigated. For this purpose, compressive and flexural strength parameters of regular concrete and fiber concrete with steel fibers, polypropylene and glass are studied by adding common waterproof material with different percentages. In this study, concrete parameters of pressure and bending resistance are evaluated using material available in the Khormoj and fiber and waterproof material. Crushed sand from Bushehr province was used. All the stone materials in the concrete mix were thoroughly washed in the S.S.D state. Dashtestan Cement Type 2 according to ASTM C 150 was used for the mixture. Thus, compressive strength tests were carried out at 7, 28 and 90 days on the cubic samples, and bending strength tests were implemented at 7, 28 and 90 days on cubic rectangular samples. The tests were carried out on 34 mixture designs and 408 samples. The concrete mixture contained waterproof materials including powder sbf-wr201 (acidic neutral) and powder bc40 (acidic neutral) and liquid bc39 (alkaline) and steel, polypropylene glass fiber. In this study, a mixture design was prepared based on ACI 211 recommendations for concrete without fibers by weight method. Then fibers (polypropylene, steel and glass of 2, 2, and 1% of weight cement, respectively) and the waterproof material (with percentages of 1, 1.5, and 2% of cement weight) were added separately to the concrete mixture design. Thereafter, the mixture design was calculated for each compound. Results show that waterproof materials bc40 and sbf increase the strength and flexural compressive strength, and waterproof material bc39 decreases concrete strength and flexural compressive strength. The most important result of this study is that to add 1% of waterproof materials bc40 to the fiber concrete with steel fiber increased compressive strength by 27%, compared to the control sample containing fiber in 90-day strength. Also, in the flexural strength of this combination no significant change is seen. Keywords: Water proof materials, Fiber concrete, Compressive strength, Flexural strength 214