Production of Hard Grade Bitumen for Using in High Modulus Asphalt Concrete

قد تتعرض الخرسانة الاسفلتية الاعتيادية لعدة اضرار مثل شقوق الكلل والتخدد وتتفاقم درجة هذه الاضرار مع الظروف المناخية القاسية والحمل المروري المتكرر. يمكن اعتبار الخلطة الاسفلتية العالية المرونة المصممة وفقا للطريقة الفرنسية (EME)) أحد الحلول المهمة للحد من هذه الاضرار. ان انتاج هذا النوع من الخليط يتطلب اسفلت (كمادة رابطة) عالي الصلابة. البحث الحالي يتضمن طريقة جديدة لأنتاج الاسفلت بتدرج اختراق نوع hard)) ليلائم متطلبات الاسفلت العالي الصلابة المستخدم لأنتاج الخلطة الاسفلتية العالية المرونة المصممة وفقا للطريقة الفرنسية. العمل المختبري يتضمن خلط البوليمر ومصلبه مع الاسفلت الاعتيادي لأنتاج الاسفلت الجديد العالي الصلابة. نظرا لأن شقوق الكلل هي أكثر المخاوف المتعلقة بالأسفلت (كمادة رابطة) العالي الصلابة والخلطة الاسفلتية العالية المرونة، لذلك تمت إضافة حبيبات المطاط الى الاسفلت المنتج العالي الصلابة لتحسين أداء التبليط في مقاومة شقوق الكلل. تم اجراء اختباري مطياف الاشعة تحت الحمراء ومسح المجهر الالكتروني للأسفلت الاعتيادي وللأسفلت العالي الصلابة. كانت القيمة المثلى المختارة للمضافات لانتاج الاسفلت العالي الصلابة المستخدم في الخلطة الاسفلتية العالية المرونة هي 4% و0.4% من وزن الاسفلت للنوفولاك والهكسامين على التوالي، بينما نسبة حبيبات المطاط لتحسين المرونة هي 0.5%. أظهرت نتائج الاختبارات المجهرية والاشعة تحت الحمراء للاسفلت المنتج حدوث تداخلا ميكانيكيا بين الاسفلت والمضافات أدى الى تحسن كبير في الخواص الميكانيكة للاسفلت المنتج. الاسفلت المنتج قد حقق متطلبات الاسفلت العالي الصلابة وبالتالي يمكن استخدامه في انتاج الخلطة الاسفلتية العالية المرونة المصممة وفق الطريقة الفرنسية.The conventional Hot Mix Asphalt (HMA) may suffer from several distress such as fatigue cracks and rutting. These distresses increase with severe climate conditions and reputation of traffic load. The High Modulus Asphalt Concrete (HMAC) designed according to the French method (EME) can be considered as one of the important solutions for these distresses. The production of HMAC requires hard grade bitumen. The current research involved a novel way to produce hard grade bitumen (asphalt binder) to be consonant with the requirements of hard grade bitumen used for a HMAC. The experimental work involved mixing polymer and cross-linking agent with conventional bitumen to get the new bitumen. Since the most concern with hard grade bitumen and HMAC is the fatigue cracks, Crumb Rubber (CR) was added to the obtained bitumen to improve the fatigue performance of the pavement. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electronic Microscope (SEM) tests were carried out on the conventional and hard grade bitumen. The optimal value of additives was selected to meet the requirement of hard grade bitumen was 4% Novolac from weight of bitumen and 10 % of Hexamine from weight of Novolac (i.e. 0.4% of weight of bitumen), while the selected CR ratio to improve flexibility was 0.5% from weight of bitumen. FTIR and SEM test results showed that a mechanical interaction was occurring between the bitumen and the additives leads to greatly improve the mechanical properties of resulting bitumen. The obtained bitumen is satisfied to required standards and can be used for HMAC according to French method

Fabrication of ZnO/nanobentonite as a new efficient adsorbent for rapid elimination of xylenol orange dye

A novel ZnO-nanobentonite (ZnO/NB) nanocomposite was successfully prepared using hexadecyltrimethylammonium bromide (HDTMA) as a surfactant and used as an efficient adsorbent to remove the xylenol orange (XO) from aqueous solutions. The fabricated nanocomposite was fully characterized by FTIR, FESEM, XRD, EDX, and BET measurements. The ZnO33%/NB sample with a high SBET and low total pore volume compared with the nanobentonite clay, based on BET results, indicated an increase in SBET due to the incorporation of ZnO nanoparticles into the layer of nanobentonite. For achieving the optimum condition, the effect of ZnO33%/NB sorbent dosage, initial pH, reaction time, and primary dye concentration, on XO dye elimination was investigated. The result show that the 97% elimination of XO dye occurred at optimum condition (40 mgl/l of dye concentration, pH 2, 15 mg of ZnO33%/NB adsorbent at 30 minutes), and the adsorption capacity and residual XO after treatment at this conditions is 48.5 and 1.2 ppm, respectively. Langmuir models and Freundlich model were used to studying the adsorption isotherms of the elimination process and results authenticated that XO dye adsorption followed the Langmuir model. Also, the recycling experiments showed that ZnO33%/NB adsorbent had more stability and recoverability. High adsorption capacity, simple fabrication method, short reaction time, and supreme reusability of ZnO33%/NB nanocomposite make it an effective sorbent for the elimination of XO dye from wastewaters

Effect of friction stir welding on microstructure and mechanical properties of the 6061 aluminium alloy/15vol % SiCp reinforcement

In this article, the microstructure and mechanical properties of friction stir-welded joints were evaluated after 15 vol. % of silicon carbide particle (SiCp) were introduced into the joint line, then compared with another welded joint without using SiCp. The rotational speed of 1750 rpm was applied during the friction stir welding (FSW) process. The microstructure was assessed at the stir zone (SZ) using Field Emission Scanning Electron Microscopy (FESEM), and results showed a banded structure of the particle-rich region of SiCp. The ultimate tensile strength (UTS) was enhanced by 79.6 %, due to the presence of SiCp. This strength increased significantly due to the pinning effect and enlarged nucleation sites associated with the SiCp. Furthermore, the reinforced particles induced the fracturing of the primary grains and showed higher ductility when compared with the SiCp -free specimen