دانلود مقالات سومین کنفرانس بین المللی بتن و توسعه

بخش نهم:
معماری بتن

FEASIBILITY OF CONCRETE USAGE IN RURAL HOUSING IN
IRAN
G. Raheb1, A. Tarkashvand2
1Assistant Professor, Building & Housing Research Center, Tehran, Iran
2Ph.D., School of Architecture & Urban Studies, Iran, University of Science & Technology, Tehran,
Iran
ABSTRACT
Concrete has been used since the 1970s in construction of rural houses in Iran.
Despite extensive use of concrete in rural housing in Iran and the huge allocated
budget, the quality of construction is not acceptable. The aim of this paper is to
evaluate the influence of using concrete in construction of rural houses in Iran. For
this purpose, the effective factors on the development process of rural housing have
been identified first. They could be counted as:
1. Efficiency and Effectiveness
2. Compatibility with climate, economy and social aspects
3. Dynamism and Flexibility
4. Stability and Durability
5. Cultural continuity and visual desirability
Then, sample cases -25 villages- have been surveyed through these factors by
authors. Minimum of 3 houses have been surveyed in each village. The result of
this research recognizes some problems of using concrete in rural housing in Iran.
The most common difficulties are providing materials with good quality, lack of
technical knowledge in villagers as the main workforces and lack of required
equipments.
Keywords: rural housing, feasibility, concrete

لینک دانلود: http://persiandrive.net/454201

بخش دهم:
ملاتهای خشک و آماده

A LABORATORY INVESTIGATION ON THE EFFECTIVE
PARAMETERS OVER THE PENETRABILITY OF ROLLER
COMPACTED CONCRETE
V. Khalili Khorram1, A. Mansouri2, H.R. Vosoughifar3
1M.Sc.Student Hydraulic Structures, Islamic Azad University Tehran South Branch
2Assistant professor Hydraulic Structures, Islamic Azad University Tehran South Branch
3Assistant professor Hydraulic Structures, Islamic Azad University Tehran South Branch
ABSTRACT
Roller Compacted Concrete construction technique has been recently remarkably
considered in Iranian academic centers and dam engineering industry. However,
research studies can hardly be found in which physico - mechanical properties of
RCC have been studied as in a real ongoing project. In this study, permeability of
the mass of RCC mixture used in Zirdan RCC dam located in south of Iran, the
second large RCC dam in Iran has been investigated. Influences of cementitious
material content, water - cement ratio, pozzolan replacement ratio in cementitious
material, delay in working time and age of concrete specimens on permeability
coefficient have been studied. Moreover, effects of different types of pozzolan on
permeability have been examined.results showed that RCC has an equal or even
lower permeability coefficient in comparison to an equivalent ordinary concrete.
Effect of water content on permeability was considerable and in comparison to
cementitious material content, showed a higher degree of importance. The rate of
developing permeability coefficient (decreasing) was found faster than the rate of
mechanical strength development (increasing). Delay in working time decreased
the permeability of RCC. However, decreasing the water content below its
optimum limit would result in an excessively high permeability coefficient.
Finally, it was observed that silica fume had a significant effect on permeability
coefficient.
Keywords: RCC, permeability coefficient, pozzolan, silica fume, working time

لینک دانلود: http://persiandrive.net/48887

ارائه طرح اختلاط مناسب بتن غلتكي سد زيردان از طريق روش آزمايشگاهي
عباس منصوري 1، حميد رضا وثوقي فر 2، وحيد خليلي خرّم 3
1. استاديار دانشكده مهندسي عمران، دانشگاه آزاد اسلامي واحد تهران جنوب
2. استاديار دانشكده مهندسي عمران، دانشگاه آزاد اسلامي واحد تهران جنوب
3. دانشجوي كارشناسي ارشد سازه هاي هيدروليكي، دانشگاه آزاد واحد تهران جنوب
چكيده
مطرح است، تعيين طرح اختلاط بتن غلتكي مي باشد كه با توجه RCC يكي از مسايل مهمي كه در زمين ه سدهاي
و عدم تجربه كافي در ايران، معمولا وقت و هزينه زيادي را م ي طلبد . در اين RCC به جديد بودن نسبي بتن
مقاله، هدف بررسي عوامل موثر بر خواص بتن غلتكي و ارائه نحوه دستيابي به طرح اختلاط بهينه بتن غلتكي با
توجه به سه معيار مقاومت فشاري، كارايي مناسب و عدم جداشدگي دان هها مي باشد.
در اين راستا به اين روش عمل شد كه تعداد زيادي طرح اختلاط با سنگدانه هاي شكسته و طبيعي ساخته شد و
اثرات نوع و مقدار سيمان وپوزولان، نوع و دانه بندي مصالح سنگدانه اي، نوع و م قدار مواد افزودني و مقدار آب بر
روي خواص بتن غلتكي خصوصا مقاومت فشاري و كارآيي مورد بررسي قرار گرفته است . سنگدانه هاي مصرفي
در چهار گروه طبقه بندي گرديدند و داراي حداكثر اندازه 50 ميليمتر م يباشند.
يافته ها حاكي از آن است كه ميزان مصالح ريزدانه در حدود 9 الي 11 درصد حجمي كل مصالح مناسب است .
همچنين جداشدگي سنگدانه حساسيت زيادي به تغييرات ميزان آب دارد . ضمنا افزودن پوزولان تا 30 درصد
حجمي سبب بهبود خصوصيات بتن سخت شده مي شود. در ضمن طرحهاي حاوي افزودني منتخب حدود 12
از Chrysoplast درصد مقاومت فشاري بالاتري نسبت به طرحهاي دي گر كسب كردند . همچنين با افزايش دوزاج
0,6 به 0,8 درصد در شرايط يكسان، حدود 9 درصد افزايش مقاومت و 3 درصد نيز كاهندگي آب بيشتر حاصل
برعكس شاهد كاهش در مقاومت هستيم. Conplast شده است. ولي با افزايش دوزاج
نتايج آزمايشات نشان مي دهد كه سنگدانه هايي كه داراي مقدار زيادي ريزدانه هستند، مقاومت فشاري مطلوبي
نتيجه نمي دهند و سنگدانه هايي كه فاقد مقدار كافي ريزدانه هستند از مقاومت فشاري خوبي برخوردارند ولي
درآنها جداشدگي دانه ها رخ مي دهد. همچنين مقدار كم آب يا زياد باعث جداشدگي دان ه ها مي شود . استفاده از
پوزولانها امكان جداشدگي دان هها را كاهش داده و موجب بالا رفتن ميزان خميرم يشود.
سد وزني، طرح اختلاط ،RCC ، كليدواژه ها: بتن

لینک دانلود: http://persiandrive.net/314107

بخش یازدهم:
بتن و ریز فناوری (نانو تکنولوژی)

INVESTIGATION OF MECHANICAL AND PHYSICAL
PROPERTIES OF MORTARS CONTAINING SILICA FUME AND
NANO-SIO2
A. Sadrmomtazi1, A. Fasihi2
, F. Balalaei3, A.K. Haghi4
1Assistant Professor, Dept. of Civil Engg, Faculty of Engg, University of Guilan, Rasht, Iran
2M.S. Student, Dept. of Civil Engg, Faculty of Engg, University of Guilan, Rasht, Iran
3M.S., Fanavari Park of Guilan, Rasht, Iran
4Professor, Dept. of Textile Engg, Faculty of Engg, University of Guilan, Rasht, Iran
ABSTRACT
It has been found that physical properties of concrete, particularly strength and
permeability significantly depend on its pore structure. Ultra fine particles of nano-
SiO2 fill the voids of CSH structure and provide more homogenous distribution of
hydrated products. This effect of nano-SiO2 enhances the durability of cement
composites as well as the strength. In this paper, influence of nano-SiO2 on
different properties of cement mortar was investigated in comparison with silica
fume (SF) as a well-known active pozzolan. Different amounts of nano-SiO2 (0,
1%, 3%, 5%, 7%and 9%) were incorporated into the ordinary cement mortar.
Mechanical properties, shrinkage, water absorption of the specimens were
determined. Results showed that the optimal content of Nano-SiO2 in plain cement
mortar was around 7%. Nano-SiO2 particles were more effective in developing
higher mechanical strength and lower water absorption than that of SF. Yet the
mortar containing nano-SiO2 experienced higher shrinkage than that of SF mortar.
Keywords: cement mortar, mechanical properties, nano-SiO2, silica fume,
shrinkage

لینک دانلود: http://persiandrive.net/915256

EFFECT OF POLYPROPYLENE FIBERS ON MECHANICAL AND
PHYSICAL PROPERTIES OF MORTARS CONTAINING
NANO-SIO2
A. Sadrmomtazi1, A. Fasihi2
, A.K. Haghi3
1Assistant Professor, Dept. of Civil Engg, Faculty of Engg, University of Guilan, Rasht, Iran
2M.S. Student, Dept. of Civil Engg, Faculty of Engg, University of Guilan, Rasht, Iran
3Professor, Dept of Textile Engg, Faculty of Engg, University of Guilan, Rasht, Iran
ABSTRACT
It has been demonstrated that the fiber-matrix bond strongly affects the ability of
fibers to stabilize crack propagation in the matrix. As the bond between fiber and
matrix is mainly mechanical, it seems that incorporating nano-SiO2 (NS) into fiber
reinforced cement composites provides better bond with matrix through pore
refinement and better distribution of the hydrated products. Hence in this paper an
effort was made to study the effect of polypropylene (PP) fibers on mechanical
properties and shrinkage of mortar incorporating NS. Three fiber volume fractions,
0.1%, 0.3% and 0.5% were considered. Compressive and flexural strength, water
absorption and shrinkage of mortars were reported. Results showed that NS
improved mechanical and water absorption characteristics of mortars significantly.
It has been observed that the addition of NS fairly enhanced the fibers effectiveness
in improving the mechanical strength of mortars.
Keywords: mortar, nano-SiO2, compressive strength, flexural strength, shrinkage

لینک دانلود: http://persiandrive.net/615764

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