الفهرس 
CHAPTER (1): IntroductionOnly 14 pages are availabe for public view
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Abstract
Nowadays the world is heading towards sustainable buildings by increasing energy efficiency, reusing waste materials, and reducing CO2 emissions not only during construction but also during service life of buildings. Recently, foamed concrete was introduced as a new alternative for conventional concrete which serves a great rule in improving the sustainability of buildings due to using industrial by-products, such as fly ash and slag in addition to its high thermal insulation. Moreover, foamed concrete has other distinguished properties such as high fire resistance, low self-weight, and high sound insulation. However, till now the most common applications of foamed concrete are limited to geotechnical applications and on roof decks, which is attributed to its low compressive strength compared to normal concrete.
Masonry walls are one of the main constructing elements of most buildings which account for a significant portion of its dead load. Traditional masonry walls are usually built using concrete or clay bricks which are small heavy units. Introducing Lightweight concrete blocks as an alternative for clay bricks in masonry walls is a good application for Lightweight concrete. Lightweight concrete blocks have several types classified according to the way of manufacturing such as: Autoclaved aerated concrete (AAC) blocks and Foamed Concrete (FC) blocks.
Autoclaved aerated concrete is widely attracted because of its excellent environmentally friendly characteristics and thermal insulation property. AAC is used as a green construction material that has been used to construct the highest rated green structure. It consumes the least amount of energy and material per cubic meter of product, making it the most energy and resource efficient. Unlike clay brick manufacturing, which wastes valuable agricultural soil.
Manufacturing of masonry blocks using foamed concrete can be considered a promising application. The large size and smooth surface of foamed concrete blocks increase mason’s productivity and reduce required packing and plastering mortar. Masonry walls built from foamed concrete blocks can offer additional advantages such as excellent thermal and sound insulation, fire resistance, in addition to minimizing the overall dead load allowing for higher construction and longer spans.
Because of their unique advantages as masonry walls in RC skeleton buildings, foamed concrete blocks have gained popularity in the masonry market recently. The production of foamed concrete blocks in Egypt is new and therefore there is a need to study their behavior and develop it to satisfy specified physical and mechanical properties. Also, characterization of its key engineering properties is needed for the development of the mathematical model, analysis, evaluation, and design of structures.
This study consisted of two phases, the first phase aimed at studying the physical and mechanical properties of foamed concrete blocks in comparison to AAC blocks. The second phase aimed at investigating the structural behavior of AAC and FC masonry walls through studying their bond, compressive, and flexural strengths. The variables considered in the second phase were the block type and the effect of plastering, in addition to spanning direction for flexural walls. To assess the out of plane behavior of AAC and FC masonry walls, six vertically spanning walls (loading span perpendicular to bed joint); three with plastering and three without plastering, and six horizontally spanning walls (loading span parallel to bed joint); three with plastering and three without plastering were constructed from each block type and tested in flexure under out of plane loading. The test results of each wall were presented in the form of failure modes and load-deflection curve.
The test results showed that the behavior of AAC and FC masonry walls are similar to that of conventional walls. AAC masonry walls exhibit higher out of plane flexural strength by approximately 1.5 times that of FC masonry walls which is attributed to the higher mechanical properties of AAC blocks compared to FC blocks. Both AAC and FC masonry vertically spanned walls showed 39% - 50% higher out of plane flexural strength compared to horizontally spanned walls. Plastering increased the out of plane flexural strength by 1.4 - 1.8 times for AAC masonry walls and by 2.4 - 4.1 times for FC masonry walls. Plastering mitigates the influence of both spanning direction and block strength on out of plane flexural strength for both AAC and FC masonry walls.