مهندسی سازه و ساخت

مهندسی سازه و ساخت

بررسی آزمایشگاهی تأثیر درز سرد بر مقاومت فشاری و کششی بتن

نوع مقاله : علمی - پژوهشی

نویسنده
مربی ،گروه مهندسی عمران،دانشگاه فنی و حرفه ای،تهران،ایران
چکیده
درز سرد یکی از چالش‌های اجرایی رایج در سازه‌های بتنی است که می‌تواند تأثیر منفی قابل‌توجهی بر مقاومت مکانیکی بتن، به‌ویژه در برابر نیروهای فشاری و کششی، داشته باشد. هدف این پژوهش، بررسی تأثیر درز سرد و ارزیابی عملکرد راهکارهای تقویتی شامل کلید برشی و شیار سطحی در بهبود مقاومت نمونه‌های دارای درز سرد است. برای این منظور، مجموعه‌ای از نمونه‌های مکعبی برای آزمون فشار و استوانه‌ای برای آزمون کشش در شرایط کنترل‌شده آزمایشگاهی ساخته شد. نمونه‌ها در چهار گروه شامل بتن یکپارچه (بدون درز سرد)، بتن دارای درز سرد، و بتن دارای درز سرد تقویت‌شده با کلید برشی و شیار سطحی مورد بررسی قرار گرفتند. نتایج آزمایش‌های کششی نشان داد که وجود درز سرد موجب کاهش 25 درصدی مقاومت کششی نسبت به نمونه شاهد شده است. استفاده از کلید برشی این کاهش را به 10 درصد و شیار سطحی به 17 درصد کاهش رساند. همچنین در آزمون فشاری، نمونه دارای درز سرد 12 درصد کاهش مقاومت نسبت به نمونه یکپارچه داشت، در حالی که این مقدار برای نمونه‌های دارای کلید برشی و شیار سطحی به ترتیب 7 و 10 درصد بود. بر اساس نتایج به‌دست‌آمده، هر دو روش تقویتی عملکرد قابل‌توجهی در بهبود اثرات منفی درز سرد نشان دادند. همچنین، مقایسه نتایج نشان می‌دهد که درز سرد تأثیر کمتری بر مقاومت فشاری نسبت به مقاومت کششی داشته است، که این موضوع بیانگر حساسیت بیشتر ناحیه درز سرد به تنش‌های کششی است و نیاز مند بررسی دقیق تری می باشد.
کلیدواژه‌ها
موضوعات

عنوان مقاله English

Experimental Investigation of Cold Joint Effects on the Compressive and Tensile Strength of Concrete

نویسنده English

amir atashi
Instructor,Department of Civil Engineering, Technical and Vocational University (TVU), Tehran, Iran
چکیده English

Cold joint is one of the common construction challenges in concrete structures that can significantly reduce the mechanical strength of concrete, particularly under compressive and tensile stresses. The aim of this study is to investigate the effect of cold joints and to evaluate the performance of strengthening techniques, including shear keys and surface grooves, in improving the strength of specimens containing cold joints. In this study, a series of cubic specimens for compressive tests and cylindrical specimens for tensile tests were cast under controlled laboratory conditions. The specimens were categorized into four groups: monolithic concrete (without cold joint), concrete with a cold joint, and concrete with a cold joint strengthened by shear keys and surface grooves. The results of the tensile tests showed that the presence of a cold joint led to a 25% reduction in tensile strength compared with the control specimens. The use of shear keys reduced this loss to 10%, while surface grooves limited it to 17%. In the compressive tests, the specimens with a cold joint exhibited a 12% reduction in compressive strength compared to the monolithic specimens, whereas this reduction for the specimens with shear keys and surface grooves was 7% and 10%, respectively. Based on the obtained results, both strengthening methods demonstrated a significant improvement in mitigating the adverse effects of cold joints. Furthermore, comparison of the results indicates that cold joints have a smaller influence on compressive strength than on tensile strength, which highlights the greater sensitivity of the joint region to tensile stresses and underscores the need for more detailed investigation.

کلیدواژه‌ها English

Cold Joint,
Compressive Strength
Tensile Strength,
Shear Key
Surface Groove
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  • تاریخ دریافت 20 اردیبهشت 1405
  • تاریخ بازنگری 21 تیر 1405
  • تاریخ پذیرش 26 تیر 1405