The extended crack resistance of concrete is necessary in the desisn of nonlinear behavior of structural It can be described through the intensity stress factor and the critical crack opening under maximum
force. The length of the crack is necessary
for calculating intensity stress factor and the critical crack opening under maximum force.
The aim of this work is to conehede the relations between intensity stress factor and the critical crack opening under maximum force with the material properties of concrete such as paste volume, compressive strength and maximum aggregate diameter. The length of crack is calculated using the analytical model of Olesen that depends on bilinear softening, and the parameters of the softening curve were found using inverse analysis. The experimental results of three point bending test for beams with different sizes which are made from concretes with different compressive strengths are used in the inverse analysis.
It is found that intensity stress factor and the critical crack opening under maximum force depend on paste volume and they increase when F'c increases, while they are independent from maximum
aggregate size.
يشكل التقدم السريع في عمليات التصنيع و خاصة في المجالات الهندسية قاعدة متينة للنهوض
بالاقتصاد الوطني ، و يساهم إدخال طرائق جديدة للإنتاج و من ضمنها أقنية الري في زيادة الإنتاج
و رفع نوعيتة.
و لما كانت مشاريع الري منتشرة على مساحة واسعة في أنحاء ال
قطر فإنَّ زيادة الإنتاج و رفع
مواصفات بيتون الأقنية يؤسس لمستقبل انتشارها، و يرفع آفاءة الري لمساحات واسعة.
و يعدُّ نظام المعالجة الحرارية مع إعادة الرج إحدى الوسائل الحديثة من أجل رفع مقاومة البيتون المائي
المستخدم.
The large increase in the volume of demolition concrete waste and its impact on the
environment has led to reconsider of using concrete demolition rubble as a partial or a
whole alternative of natural aggregates to produce new concrete which has th
e required
properties to use in engineering constructions[1]. With the possibility of improving the
mechanical properties of this concrete by processing this aggregates before using it or
support this concrete with fiber to improve its structural behavior.
This research deals with the study of the replacement the natural aggregates used in
concrete with recycled concrete aggregates resulting from the demolition rubble ,
according to different replacement ratiosranging between 0 % -25 % -50 % -75 % -100%
and the impact on the concrete behavior with a natural aggregates and determine the
optimal replacementpercentage.
The results showed a relative decrease in the concrete resistance on the simple
pressure , limited decrease in the volumetric mass also, and a slight adjustment to the
behavior of concrete under the loading effect by increasing the replacement proportion of
the natural aggregateswith recycled concrete aggregates..
This paper presents structural
analysis in using ANSYS programme for modeling of heat load then
comparison between the analytical results and experimental results is
performed .
