Cellular Concrete Blocks Research Articles

Thermal performance of a typical residential Cyprus building with phase change materials

This work investigates the thermal performance of a typical building in Cyprus, and the effect of application of a particular passive technology (phase change material or PCM) with the aim of reducing indoor air temperatures and energy supplied for the cooling season. Phase change materials for passive building applications are an emerging technology and have not been tested for the buildings of Cyprus, either by computer simulation or practical application. In this paper, the effect of incorporating a phase change material wallboard with a phase change temperature of 26℃ was investigated by simulation in Energy Plus. Four scenarios were considered for the same building geometry, each having different constructions. Two construction styles were used: perforated clay brick walls with reinforced concrete slabs and cellular concrete block walls with cellular concrete slabs. Each construction style was used in two different thicknesses. Simulations were carried out for the city of Larnaca for the cooling season only (May–October). The results showed that with this particular phase change material product, indoor air temperatures and cooling energies supplied to the building could be reduced by up to 1.7℃ and 14.0%. Practical application: Sensible heat storage in building fabric is usual practice in Cyprus, as traditional building materials are thermally heavy. This paper will have practical impact as it introduces application of PCMs, a new method for storing heat in the buildings of Cyprus in much lighter way, where the weight is significant constraint due to earthquake load.

The Utilization of Waste Aluminosilicate to Prepare Cement Composite with Thermal Insulating and Drying Effect

Increasing energy prices, along with escalating demands for thermal insulation properties of enclosure structures, force the owners of buildings to reduce the operating costs of heating. That is why the question of reducing the energy consumption of buildings, also including the category of historical buildings [10], has been gaining ground. The reduction of energy consumption of these buildings is often accompanied by the requirement to eliminate moisture problems of base structures caused by leaking or broken waterproofing of the bottom part of the object. The subsequent increase of the thermal resistance of the building envelope must be performed by means of special insulation materials allowing the drainage of liquid water from the structure. The paper presents the properties and the influence of the developed materials on the course of built-in moisture in the base structure affected by this phenomenon using Delphin simulation software, based on the measured thermal and technical parameters. The developed material is a composition of pozzolan binder, foaming agent and waste resulting from the production of cellular concrete blocks. According to tests carried out in [1], it is possible to produce concretes with sufficient strengths for rehabilitation boards when you substitute natural aggregates with waste aluminosilicate and, according to [2, 3, 4, 5, 6], you will achieve better rehabilitation and thermal insulation properties by using porous filler. The developed material is intended for the so-called soft rehabilitation, and its function is specifically presented on a structure built from sandstone blocks. This type of structures can be found in north Bohemia and the application of rehabilitation work must be very carefully considered, because quick drying of built-in moisture in masonry, for instance by means of cutting the lower part of the structure and by inserting waterproofing, will cause shape changes of the structure accompanied by the formation of cracks.

Flexural Strength and Ductility of Concrete Brick Masonry Wall Strengthened using Steel Reinforcement

In some areas, most of the damaged buildings caused by earthquakes were residential houses. The damages affect the number of casualties and socio economic losses. Most of residential houses in some countries are made of masonry walls. Because of the material cost and simple construction method, concrete brick masonry walls become widely used in Indonesia. Improving the structural performance of this kind of wall has become important. For this reason, experimental test was conducted on the flexural strength and ductility of concrete brick masonry wall strengthened by steel bar reinforcement. The concrete bricks are in the form of cellular hollow concrete blocks which used for practical residential houses popularly. The aims of the test were to determine the out of plane flexural capacity and ductility of the strengthened masonry walls by using some variation steel bars reinforcement ratio in horizontal and vertical directions of the walls. The results of the test showed that the variations of flexural strength of unreinforced wall specimen were very high. The flexural capacity and ductility of strengthened walls were increased significantly, up to 5-16 times higher than that of non strengthened walls. Steel reinforcement could increase the flexural strength close to the theoretical. Although they failed brittle, the both materials bataton bricks and steel reinforcements were non easily separate one to another.

Types of Failure in Cellular Concrete Blocks (Thermostone)

Cellular or aerated autoclaved concrete blocks ( called Thermostone in Iraq ) may undergoes several problems during and after manufacturing ,these problems cost both time and money. The present work aims to determine the main types and causes of failure occurred in cellular concrete blocks (Thermostone) during and after production process. Physical and mechanical tests, chemical analysis, as well as X-ray diffraction technique were conducted to investigate the main causes of failures and to suggest solutions. The results showed that the complete reaction (Hydrogen bubbles formation) between lime (CaO) , water ,and Aluminum powder always occurs when the minimum reaction temperature is 43 oC or more, No observed reaction took place when the hydration temperature was less than 40 oC . Aluminum powder diameter of (50-100) µm was found to be suitable for best product properties. X- Ray diffraction results showed a presence of detrimental components causing moisture spots and excessive expansion in both green and autoclaved products. Controlling raw materials, increasing autoclaving period from 10 to 14 hours or adding up to 5% limestone aggregate are essential to get a product fulfills the specifications requirements

Impact of the lifespan of different external walls of buildings on greenhouse gas emissions under tropical climate conditions

Abstract This paper presents a comparative study of greenhouse gas emissions due to different wall compositions in accordance with their lifespans. The assessments carried out take into consideration the construction, maintenance and end of life of the walls, for a specific tropical climate site. The energy spent for heating and cooling during the utilization phase of the building was made equivalent for all calculations, in order to isolate the study on the evaluation of the performance of each technical solution. Initially, the methodology is described by choosing technical solutions to the building envelope, determining the corresponding service life for each solution and finding the corresponding GHG index from an appropriate database. Then, the evolution of this indicator is calculated within a given time for the four different technical solutions: Concrete Block; Solid Clay Brick; Cellular Concrete Block; Multicell Clay Brick. Brazilian national standard materials lifespans were adopted. A building lifespan of 150 years was considered. The results of this analysis suggest and quantify the important impact of the lifespans of both the materials and the building itself on greenhouse gas emission indicators. The numerical results presented point out the need to revisit the current life cycle analysis practices.

Comparative Analysis of the Thermal Behavior between Cellular Concrete Blocks and Stabilized Earth Blocks as Wall Materials

In extreme climates like the desert climate of Northwest Mexico, indoor thermal conditions in buildings, and particularly in low-cost housing developments, are very uncomfortable. In buildings where the use of air conditioning devices can be afford, excessive energy is spent, leading to high acclimatization costs.In many cases, construction materials for low-cost houses are selected according to the lowest price, and not taking into account the best thermal behavior according to the local climate. Different types of blocks are widely used as a construction material for walls, such us earth blocks, adobe, concrete hollow blocks, cellular blocks, bricks, because of their low price and easy installation. Designstrategies must be very carefully selected according to the local climate, because they have a great impact on energy consumptions and in the quality of life of the occupants. The selection of the appropriate materials for the envelope is part of these design strategies, and is the main subject of this paper.In this work we analyze the thermal behavior of a wall compound of two different materials: cellular concrete blocks and stabilized earth blocks. The monitored wall is part of a low-cost house constructed for demonstrative and experimental purposes. External and internal superficial temperatures have been measured and infrared images of the same areas have been analyzed.Infrared thermography is particularly useful to evaluate non-homogeneous materials or non-traditional materials, from which not all thermal properties are known. The thermal behavior is analyzed, in relation to the expected characteristics according to the climate, such as adequate thermal insulation and thermal inertia of the envelope, which are different for air-conditioning and non air-conditioning situations.

English

Cellular concrete blocks are the major building materials in Kurdistan Region in Iraq. This study is carried out to check the economical and structural feasibility. The integrity of the blocks as well as its industrial production process compared with local and international standards. Recommendations for the concrete block production have been given in this paper. Samples from 10 local factories of total 60 blocks have been collected and tested at Koya University Laboratory. The carried out tests covered the dimensions, compression strength and water absorption of the samples. The results of this research study were compared with the requirements of the Iraqi and European specifications. They showed that the products of all factories do not fulfil the specified requirements. The dimensions of specimens exhibited relatively high deviations with no recommended tolerances for dimensions of the blocks. The results analysis showed that the weight of the 400x200x200mm block size was about 20-23 kg and the size of the represented voids was about 60% of the volume. This study made some regulatory recommendations to standardise the concrete block production in the region.

Partially rib precast and cast-in-situ floors with cellular-concrete blocks

Partially rib precast and cast-in-situ floors with cellular-concrete blocks

Greening of Mortars with Pozzolans

Abstract Growing interest in sustainable building has created a strong interest in fly ash and other coal combustion products (CCPs). Emergence of agencies like the U.S. Green Building Council (USGBC) and the Coal Combustion Products Partnership (C2P2) of the USEPA has accelerated this trend. Their primary goal is sustainable development, focusing on environmental and social concerns. More than 30% of the 100 million tons of coal combustion products produced in the U.S. annually are being beneficially used in such things as manufactured stone, ceramic tile, shingles, concrete, aerated cellular concrete blocks, concrete blocks, stuccos, and mortars. The use of CCPs positively impacts the environment. Specifiers, contractors, and industry need to recognize that environmental stewardship today affects our children tomorrow. The features and benefits recognized in pozzolanic mortars reach beyond the technical, environmental, social, and sustainable aspects of this mortar. They signal future generations to track, improve, and develop mortars beyond any of our current technology.

Full-scale dynamic testing of a steel frame building during construction

Full-scale testing of a six-story steel frame building with infill walls made primarily of autoclaved cellular concrete and curtain walls made of hollow core clay bricks using ambient and forced vibration methods are described in detail. The ambient vibration test took place in two stages of the construction—stage one, when only the frames and slabs where constructed, and stage two when all the walls were put in place. The forced vibration was carried out when some of the walls were constructed. The results from the two test methods are compared with each other and also with computer analysis results based on conventional design office assumptions for modeling. Dynamic characteristics of the structure including natural frequencies, damping ratios and mode shapes determined from the tests are presented. The effect of Autoclaved Cellular Concrete (ACC) block infill and partition walls on the dynamic properties and stiffness of the building are discussed in detail. The advantages of using ACC block walls as infill wall material for seismic regions are concluded.

Ferrocement: Alternative Material for Secondary Roofing Elements

The appcicability of ferrocement as an alternative material for secondary roofing slabs was investigated. The performance of such slabs was compared to those of cellular concrete slabs and commercially available 'hollow blocks.' Tests carried out include flexural and patch load tests, initial surface absorption tests, and shrinkage measurements. The effects of carbonation, weathering, and thermal stresses were also studied. Results indicated that ferrocement slabs have a higher resistance against cracking and carbonation. They are more impermeable and have lower long-term shrinkage. In general, the effects of weathering and thermal stresses are found to be least detrimental in ferrocement slabs than in cellular concrete slabs and hollow blocks.

Mechanics of Overflow Erosion on Embankments. I: Research Activities

Part I of a two‐part report presents model and prototype research studies which have been conducted in the United States and Great Britain to evaluate how embankments for dams, levees, roadways, etc. perform when subjected to overtopping flows from probable maximum flood (PMF) or near‐PMF events. With improvements in the collection of flood records and the development of estimated storm events a significant increase in predicted PMF has been realized in some areas of the United States and other countries. These studies provide the engineer with an understanding of the mechanics of overflow erosion through subjecting scale model and prototype embankments to overtopping flow events. The effectiveness of various protection systems in preventing overflow erosion is evaluated. These systems range from grass‐lined embankments and spillways to more sophisticated protection using geotextiles, gabions, riprap, cellular concrete blocks and soil cement. Such research efforts provide for the development of cost‐effective measures that allow embankments to pass these extreme flood events without breaching.

Discussion of “Cellular Concrete Block Revetment”

Discussion of “Cellular Concrete Block Revetment”