نتایج جستجو برای: natural aggregates

تعداد نتایج: 508782  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1392

abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...

In recent decades, the use of self-consolidating concrete has become widespread. Hence, recognizing the various properties of self-consolidating concrete are essential. In this study, several mixture designs have been tested and final mixture design of crushed tile aggregates which were replaced by 0%, 25 %, 50%, and 100% volume percentage of natural aggregates were conducted. To evaluate fresh...

2006
A. Eynard

Soil wettability is especially important for rainfed agriculture in climates with a dry period during the growing season. The effect of aggregate structure and soil organic C content on wettability of soil aggregates was determined for grassland (grass) and tilled fields (tillage). Soil organic C, plastic limit, aggregate total porosity, and wettability at 100 mm (rapid wetting) and 300 mm (slo...

2015
Laura Garach Mónica López Francisco Agrela Javier Ordóñez Javier Alegre José Antonio Moya

Recycled concrete aggregates and mixed recycled aggregates are specified as types of aggregates with lower densities, higher water absorption capacities, and lower mechanical strength than natural aggregates. In this paper, the mechanical behaviour and microstructural properties of natural aggregates, recycled concrete aggregates and mixed recycled aggregates were compared. Different specimens ...

Journal: :International Journal for Research in Applied Science and Engineering Technology 2017

Journal: :پژوهش های خاک 0
علی عطایی دانشجوی دکتری دانشگاه تبریز منوچهر گرجی دانشیار گروه علوم خاک دانشگاه تهران یحیی پرویزی استادیار مرکز تحقیقات کشاورزی کرمانشاه

a major concern of farmers is deterioration of the soil and water resources. soil management is the most direct way for mankind to interfere with natural processes that may either intensify or hinder soil degradation. fractal geometry has been widely used to describe heterogeneity in a wide range of natural processes, including physical systems of soil. in this study, the effects of different m...

A. Sadrmomtazi, J. Sobhani, M. A. Mirgozar, M. Ejtemaei,

Lightweight concrete (LWC) is a kind of concrete that made of lightweight aggregates or gas bubbles. These aggregates could be natural or artificial, and expanded polystyrene (EPS) lightweight concrete is the most interesting lightweight concrete and has good mechanical properties. Bulk density of this kind of concrete is between 300-2000 kg/m3. In this paper flexural strength of EPS is modeled...

Ali Delnavaz, Moslem Mohammadi Jatani

Given the development of construction industry and design and implementation of high rise buildings with complex sections and various geometrical forms, the use of self-compacting concretes has received the attention of construction engineers and provided great advantages. Due to the increasing air pollution in cities, governments encounter the important issue of repelling the pollutants in whi...

2015
Ginevra Balletto Chiara Garau Vivian W. Y. Tam

Despite its economic importance, quarrying activity for the production of natural aggregates (sand, gravel, and crushed stone) can result in overexploitation of the natural environment. This paper investigates the current state of natural and recycled aggregates in Sardinia Italy and how to limit the production of natural aggregates (NA) and increase the use of recycled aggregates (RA). The mun...

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