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ارزیابی اثر مقدار مادهی هوازا در کاهش شدت ترک خوردگیهای ناشی از جمع شدگی خمیری در روسازیهای بتنی هوادار | ||
| نشریه مهندسی عمران امیرکبیر | ||
| دوره 54، شماره 2، اردیبهشت 1401، صفحه 457-474 اصل مقاله (1.94 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22060/ceej.2021.18914.6996 | ||
| نویسندگان | ||
| سید جواد وزیری کنگ علیائی1؛ سینا گلچین2؛ اسما سادات دبیری1؛ حسن فضایلی* 2 | ||
| 1دانشکده مهندسی عمران، دانشگاه علم و صنعت ایران، تهران، ایران | ||
| 2دانشکده مهندسی عمران، دانشگاه آزاد واحد تهران-شمال، تهران، ایران. | ||
| چکیده | ||
| ترک خوردگی ناشی از جمع شدگی خمیری یکی از خرابیهای شایع در روسازیهای بتنی بوده که باعث کاهش دوام و سطح سرویس جاده میگردد. استفاده از مواد افزودنی مختلف به مقدار بهینه میتواند باعث کاهش این ترک خوردگی گردد. این تحقیق به بررسی اثر مقدار مصرف ماده هوازا در ایجاد هوای عمدی در روسازیهای بتنی هوادار، در کنترل یا کاهش شدت ترک خوردگیهای ناشی از جمع شدگی خمیری میپردازد. بدین منظور اثر افزودن مادهی هوازا به مقدار 0/04، 0/07 و 0/10 درصد وزن سیمان بر شدت ترک خوردگیهای خمیری در طرحهای اختلاط بتن روسازی با نسبتهای آب به سیمان 0/40، 0/45 و 0/49 ، با استفاده از روش ASTM C1579 بررسی شد. نتایج نشان داد که افزودن مادهی هوازا، باعث کاهش شدت ترک خوردگی خمیری در بتن هوادار نسبت به بتن معمولی گردید. دیده شد که با مصرف بیشتر مادهی هوازا از یک درصد مشخص، شدت ترک خوردگی بیشتر شده که این مقدار مصرف مشخص و بهینه، در این تحقیق به میزان 0/07% به دست آمد. نتایج نشان داد که افزایش نسبت آب به سیمان در بازههای تغییر پایینتر، اثر بیشتر بر شدت ترک خوردگی دارد. همچنین درصد هوای عمدی ایجاد شده ناشی از مصرف بهینهی مادهی هوازا، کمتر از حداکثر درصد هوای عمدی مجاز در روسازیهای بتنی میباشد. بنابراین با مصرف بهینهی این ماده، میتوان شدت ترک خوردگیهای خمیری در روسازیهای بتنی را کاهش داد. | ||
| کلیدواژهها | ||
| مادهی هوازا؛ هوای عمدی؛ روسازی بتنی هوادار؛ ترک خوردگی ناشی از جمع شدگی خمیری؛ مقدار مادهی هوازا | ||
| موضوعات | ||
| انواع خرابی روسازی صلب؛ تعمیر و تقویت روسازی؛ تکنولوژی بتن | ||
| عنوان مقاله [English] | ||
| Assessment of the Effect of Air-Entraining Agent Content in Reducing the Severity of Plastic Shrinkage Cracking in Air-entrained Concrete Pavements | ||
| نویسندگان [English] | ||
| Seyed Javad Vaziri Kang Oleyaei1؛ Sina Golchin2؛ Asma Sadat Dabiri1؛ Hassan Fazaeli2 | ||
| 1Highway Engineering and Transportation, school of civil engineering, Iran University Of science and Technology, Tehran,Iran | ||
| 2Transportation, School of civil engineering, Islamic Azad University Tehran-North Branch, Tehran, Iran | ||
| چکیده [English] | ||
| Plastic shrinkage cracking is one of the most common distress in concrete pavements, which reduces the durability and level of service. Using different admixtures in the optimal amount can reduce these cracks. This study investigates the effect of air-entraining agent content in creating intentional air in air-entrained concrete pavements, in controlling or reducing the severity of plastic shrinkage cracking. For this purpose, the effect of adding air-entraining agent in the amount of 0.04, 0.07, and 0.10% by weight of cement on the severity of plastic shrinkage cracking in concrete pavement mixture with water to cement ratios of 0.40, 0.45, and 0.49 was investigated by using ASTM C1579 method. The results showed that the addition of air-entraining agent reduced the severity of plastic shrinkage cracking in air-entrained concrete compared to the conventional one. It was seen that with more addition of air-entraining agent than a certain amount, the severity of cracking has increased, which is a specific and optimal amount of 0.07% in this study. The results showed that increasing the water to cement ratio at lower change intervals has a greater effect on the severity of cracking. Also, the percentage of entrained air due to the addition of the optimal amount of air-entraining agent is less than the maximum percentage of allowed entrained air in concrete pavements. Therefore, with the use of this admixture in the optimal amount, the severity of plastic shrinkage cracking in concrete pavements can be reduced. | ||
| کلیدواژهها [English] | ||
| Air-entraining agent, Entrained air, Air-entrained concrete pavement, Plastic shrinkage cracking, Air-entraining agent content | ||
| مراجع | ||
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