21356

21356

بررسي عملكرد مخلوط‌‌هاي بتن و ملات خودتراكم حاوي افزودني‌‌هاي جايگزين سيمان در شرايط مختلف روياروئي آب درياي خليج فارس

كارشناسي ارشد

مديريت ساخت و پروژه

1398

1398/8/11

دكتر علي اكبر شيرزادي جاويد - دكتر سيد سجاد ميرولد

عمران

سالهاست كه خليج‌‌فارس بدليل شرايط محيطي خاص منطقه همچون رطوبت، دما، مقدار كلرايد زياد و همچنين جغرافياي بسته‌‌ي آن به محيط بسيار مخرب و حساس براي دوام سازه‌‌هاي بتني در معرض تهاجم آب دريا شناخته شده‌‌است و يافتن طرح‌‌هاي بادوام در اين منطقه حائز اهميت است. در اين پژوهش بمنظور بررسي اثر مواد جايگزين سيماني بر دوام بتن‌‌هاي خودتراكم چهار‌‌جزئي و سه‌‌جزئي حاوي زئوليت و دوده‌‌ي‌‌سيليسي و پودر‌‌سنگ‌‌آهك بعنوان پر‌‌كننده ي غير‌‌فعال در شرايط مختلف روياروئي با آب خليج‌‌فارس اعم از مغروق، جزر‌‌ و‌‌ مد و پاشش، نمونه‌‌هاي بتن و ملات خودتراكم با نسبت آب به مواد سيماني ثابت 45/0 و مقدار مواد سيماني 380 كيلوگرم بر مترمكعب ساخته شد و از نمونه‌‌هاي بتن آزمايش‌‌هاي مقاومت فشاري، مقاومت الكتريكي، مقدار يون كلرايد آزاد و همچنين آزمايش‌‌هاي تخلخل كل، جذب آب موئينه، انبساط طولي و مقاومت فشاري بر روي نمونه‌‌هاي ملات انجام شد. طبق نتايج بدست آمده، افزودن زئوليت و دوده‌‌ي‌‌سيليسي (بصورت طرح چهارگانه) به نمونه‌‌ي خودتراكم سبب افزايش تمامي خواص دوامي و مقاومتي نسبت به نمونه هاي ملات و بتن كنترلي قرار گرفته در انواع شرايط رويارويي شد.

1398/09/08

Effects of Silica fume/Zeolite on Self-consolidating mortars/concretes durability exposed to various exposure conditions in a simulated marine environment

11/30/2019 12:00:00 AM

The Persian Gulf is well known as one of the most aggressive environments in the world because of its high relative humidity, temperature and concentration of chloride ions. Improving the durability of concrete structures in such environments is an important issue. In this paper, the performance of ternary and quaternary blended mortars/concretes containing natural zeolite (NZ)/silica fume (SF) and lime stone powder as an inert filler, under various exposure conditions has been investigated. To achieve this objective, self-consolidating mortar/concrete specimens containing 15% natural zeolite, 8% silica fume with total binder content of 380 kg/m3 with a constant water to cement ratio of 0.45 were fabricated. After 7 days of curing in saturated calcium hydroxide solution, all of the specimens were subjected to three exposure conditions (tidal, splash, submerged). After taking fresh property testes of mortar/concrete samples, hardened properties were investigated by mortar/concrete compressive strength, chloride permeability, concrete electrical resistivity, mortar capillary water absorption and porosity tests. Also, the degree of sulfate attack was evaluated by measuring expansion of mortar prisms. Moreover, both the conventional and SCC mixes were subjected to these durability tests in order to compare their performance. The results were obtained from a laboratory set up and indicated that when the durability properties of the concretes in such environments were taken into account, the ternary use of zeolite and silica fume provided the best performance in all exposures. Furthermore, self-consolidating concretes and mortars performed better than the normal types. The correlation between electrical resistivity and compressive strength with sorptivity of all mixes exposed to simulated Persian Gulf sea water and costs of materials were also evaluated.