International Journal of Recent Technology and Engineering (IJRTE) ISSN: 2277-3878, Volume-7, Issue-6C2, April 2019 615 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: F11120476C219 /19©BEIESP Abstract: Autoclaved aerated concrete (AAC) blocks due to their light weight, low density are extensively used as masonry units in construction in spite of these properties there exists a problem of cracking in the AAC units under high temperatures, It is also said that the blocks undergo thermal expansion. The plaster does not get adhered to the surface of units. An effort has been made to determine the strength behavior, bond behavior, crack behavior and thermal behavior of AAC blocks under varying temperatures, mortar ratios and thickness. It is found that there was reduction in the strength and formation of cracks for temperatures above 500 deg C, the bond behavior was found vary with mortar thickness and ratios. Thermal comfort study showed better thermal comfort in comparison with the model with Solid ConcreteBlock. Index Terms: AAC Blocks, mortar ratios, Bond behavior, thermal comfort, crack behaviour I. INTRODUCTION Wall being built of masonry is the major structural component which occupies 75% - 80% of the volume in building. The properties of materials used in masonry influence the thermal performance of the building envelop. Thermal performance of walls used in buildings can be increased by using insulating materials or by using materials with low thermal conductivity. Thermal performance of any building material depends on several factors and may not be assessed based on any one of the factor. The selection of material for construction contributes to thermal discomfort and hence care should be taken by choosing the right material in the design stage itself otherwise it becomes costly at the later stage. Before selecting the materials, the properties like Specific heat, thermal conductivity, transmissivity and heat transfer coefficients are to be checked to ensure the thermal performance and other load bearing properties of the building. In Indian construction scenario, lot of advancement and technology innovations are being adopted for achieving thermal comfort and energy saving. Thermal performance of advanced materials [1] to play a lead role in energy efficiency and in providing thermal comfort. Autoclaved aerated concrete blocks (AAC) are considered as low energy building material, non-toxic and highly sustainable building material to have good thermalperformance. AAC blocks are formed with a reaction of Aluminium on a proportionate blend of fly Ash, lime, gypsum and cement. During the formation, the hydrogen gas that escapes creates millions of tiny air cells giving it a strong cellular structure Revised Manuscript Received on April 15, 2019. Jagadish Vengala, Associate Professor, Department of Civil Engineering, PVP Siddhartha Institute of Technology, Vijayawada, Andhra Pradesh, India. ShivakumarMangloor, Former Undergraduate student, Department of Civil Engineering, BMSIT&M, Bangalore, India. Talla Krishna Chaitanya Goud, Former Undergraduate student, Department of Civil Engineering, BMSIT&M, Bangalore, India. which is further strengthened by high pressure steam curing in Autoclaves, thus known as Autoclaved Aerated Concrete (AAC) BLOCK. The Density of AAC blocks varies between 550 - 650 kg/m3 and the weight is less than one third of the weight of normal bricks. Autoclaved aerated concrete (AAC) blocks due to their light weight, low density are extensively used as masonry units in construction in spite of these properties there exists a problem of cracking in the AAC units under high temperatures , it’s also said that the blocks undergo thermal expansion. The plaster does not get adhered to the surface of units. Limited study is available on thermal behaviour, strength variation under high temperatures and thermal expansion of AAC blocks. Mortar joint thickness and its proper study. Keeping the above factors in mind, attempts have been made to address the above issues by conducting a series of experiments. This study was conducted based on the following objectives The main objective of this experimental program is to study the various engineering properties of AAC block such as compressive strength, density, thermal behaviour. An attempt was also made to determine the crack pattern of AAC blocks under varying temperatures. Thermal comfort studies were conducted on AAC blocks in comparison with the conventional solid concreteblocks. II. EXPERIMENTALPROGRAMME The following materials were used for thisstudy: • AAC BLOCKS: Blocks manufactured using fine aggregates, fly ash by passing hydrogen gas where used for various tests. These AAC blocks of size 600mm×200mm×150mm. • Ready JOINT MORTAR: Joint mortar proves to be good in bonding action when used with AACblocks. • MORTAR-READY PLAST: Plaster mortar proves to be good bonding and acts as an ideal plaster mortar when used with AACblocks. Following methodology was adopted to assess the performance of AAC blocks. In this regard a test program was planned and designed to carry out various studies based on the actual site conditions. Case 1: Strength behavior of block specimens under varying temperatures. Case 2: Bond behavior of masonry joints with varying mortar ratios and thickness. Case 3: Crack behavior of prisms made with block specimens under varying temperature Performance of Autoclaved Aerated Concrete Blocks Under Varying Temperatures Jagadish Vengala, Shivakumar Mangloor, Talla Krishna Chaitanya Goud
Performance of Autoclaved Aerated Concrete Blocks Under Varying Temperatures
Apr 26, 2023
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