بررسی اثر تخلخل و رطوبت در مکانیزم شکست ملات سیمان با استفاده از پارامتر های انتشار آوایی (AE)

نویسندگان
1 تربیت مدرس
2 دانشگاه تربیت مدرس
3 هیات علمی دانشگاه تربیت مدرس
چکیده
در مکانیک شکست سنگ از روش‌های متعددی برای رفتار‌نگاری رشد ترک و شکست استفاده می‌شود. یکی از روش‌هایی که برای بررسی ریزترک‌ها در نمونه‌ تحت تنش استفاده می‌شود، روش انتشار آوایی است. وجود تخلخل و رطوبت در ساختار بتن، خاک و سنگ اثرات مختلفی بر روند ایجاد و رشد ریزترک‌ها و در نهایت شکست آنها خواهد داشت. در این تحقیق اثر تخلخل و رطوبت در رشد ترک و شکست در سنگ بررسی شده است. از چهار پارامتر بسیار موثر در روند رفتار‌نگاری شکست در روش انتشار آوایی یعنی هیت، کانت، دوام موج و انرژی شکست استفاده شده است. برای داشتن درصد تخلخل یکسان و همسان در نمونه‌ها از ملات سیمان(سنگ مصنوعی) استفاده شد. با استفاده از ماده روان کننده Panplast R نمونه با تخلخل بین 17 تا 35 درصد در پنج تخلخل مختلف نمونه‌های استوانه‌ای با قطر 54 میلیمتر با نسبت طول به قطر دو ساخته شد. نمونه در دو حالت خشک و اشباع از آب تحت آزمایش تک ‌محوره فشاری قرار گرفتند. در حین آزمایش اطلاعات انتشار آوائی ثبت شد. از تحلیل داده‌های بدست آمده از روش انتشار آوایی مشخص شد که مود شکست غالب در آزمایش فشارشی تک‌محوره در نمونه‌های ملات سیمان خشک با افزایش تخلخل، به سمت مود کششی افزایش‌ یافته و با افزایش تخلخل و افزایش رطوبت ریز ترک های کمتری در نمونه ایجاد میشود.

کلیدواژه‌ها

موضوعات


عنوان مقاله English

Assessment of moisture and porosity effects in failure mechanism of mortar using Acoustic Emission

نویسنده English

morteza ahmadi 1
1 tarbiat modares
چکیده English

Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases. Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases. Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases

کلیدواژه‌ها English

Fracture mechanics
Uniaxial compressive test
Acoustic Emission method
Failure mechanism
porosity and moisture content
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