تأثير المعالجة الداخلية باستخدام كرات البوليمر الماصة للماء والركام الخفيف على الانكماش الناتج عن الجفاف في الخرسانة
محتوى المقالة الرئيسي
الملخص
يُعدّ الانكماش الناتج عن الجفاف أحد الأسباب الرئيسة لتكوّن الشقوق الدقيقة في الخرسانة وتدهور متانتها، ولاسيما في الحالات التي تفشل فيها طرق المعالجة التقليدية. تؤدي المعالجة الداخلية دورًا فعّالًا في معالجة هذه المشكلة من خلال تزويد الخرسانة بكميات مناسبة من الماء داخل المصفوفة الخرسانية للحفاظ على استمرار الإماهة والتقليل من الإجهادات الناتجة عن الانكماش. تتناول هذه الدراسة تأثير المعالجة الداخلية باستخدام كرات البوليمر الماصة للماء (WAPB) والركام الخفيف (LWA) ومزيجهما الهجين على الانكماش الناتج عن الجفاف ومقاومة الانحناء في الخرسانة. تم تحضير سبع خلطات خرسانية، شملت خلطتين مرجعيتين (Rw، Rair)، وخلطة تحتوي على WAPB، وأخرى باستبدال 50% من الركام الطبيعي بركام خفيف، وخلطة هجينة (25% LWA + 5% WAPB)، بالإضافة إلى خلطتين خفيفتين بالكامل (LWAw، LWAair).
أظهرت النتائج أن المعالجة الداخلية قلّلت بشكل ملحوظ من مقدار الانكماش الناتج عن الجفاف مقارنة بالعينة المرجعية المعالجة بالهواء. سجّلت خلطة الركام الخفيف بنسبة 50% أقل قيمة للانكماش عند عمري 28 و120 يومًا (67.5×10⁻⁶ و175×10⁻⁶ على التوالي)، في حين أظهرت الخلطة الهجينة أقل زيادة طويلة الأمد (حوالي 14%). أما مقاومة الانحناء فقد انخفضت نسبيًا في جميع الخلطات التي خضعت للمعالجة الداخلية مقارنة بالخلطة المرجعية المعالجة بالماء، ويُعزى ذلك إلى زيادة المسامية، إلا أنها بقيت ضمن الحدود الإنشائية المقبولة.
إن الجمع بين الركام الخفيف وكرات البوليمر الماصة للماء أدى إلى تقليل كبير في الانكماش مع فقدان بسيط في المقاومة، مما يؤكد كفاءة تقنية المعالجة الداخلية في تحسين أداء الخرسانة التقليدية.
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تفاصيل المقالة
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