Brazilian results on structural masonry concrete blocks

The purpose of this paper is to study the mechanical behavior of concrete blocks and prisms when performing axial compression tests within the Brazilian base of knowledge, intending to foment data of this kind for a world-based network. The blocks were built using five different mixtures in which the quantity of cement and the compacting ratio (density) were varied (during the fabrication process). The three-course-high prisms were assembled using 1 cm (0.39 in.) thick full-bedded joints, always trying to leave the mortar's characteristics constant. The axial compression tests were conducted according to Brazilian practice code recommendations, because most of these standards are very similar to international practice codes. The compressive strength, strains, and rupture form of each mixture studied were recorded. Attempts were made to correlate the strength, efficiency ratio (block strength/prism strength) of the prisms, strains, and rupture form; with the quantity of cement and compacting ratio. The data are presented in tables and figures, and the obtained results are discussed throughout the text. Copyright © 2007, American Concrete Institute. All rights reserved.

Estimate of concrete block texture using image analysis

The texture of concrete blocks is very important and is often the decisive factor when choosing a product, particularly if the building specifications call for high-strength blocks allied to low-cost finish, in which case exposed blocks with a closer texture are often preferred. Furthermore, a closer texture, especially for exteriors, may be a vital factor in ensuring the building's durability. At present, however, there is no standard to quantify the texture of a structural block. Further, when studying masonry blocks compressive strength should never be overlooked. This article discusses a procedure to produce concrete block textures with and without the addition of lime, but still to achieve the required compressive strength. The method used in this study, to evaluate texture, proved to be simpler and cheaper than methods reported by other authors in the literature. The addition of small quantities of lime proved beneficial for both texture and compressive strength. Increasing the amount of lime further, however, only improved texture.

Application of UTHSCSA-Image ToolTM to estimate concrete texture

The texture of concrete blocks is very important and is often the decisive factor when choosing a product, particularly if the building specifications does not dispense with the high resistance of the blocks, but has the purpose of reducing costs with finishing, therefore preferring exposed blocks with a closer texture. Furthermore, a closer texture, especially for exteriors,may be the vital factor of the building's pathology.However, there is so far no standard to quantify the texture of a structural block. This article proposes to apply the freely available UTHSCSA-Image ToolTM program developed by the University of Texas Health Science Center at San Antonio to evaluate the texture of masonry blocks. One aspect that should never be overlooked when studying masonry blocks is compressive strength. Therefore, this work also gets the compressive strength of the blocks with and without the addition of lime. The addition of small quantities of lime proved beneficial for both texture and compressive strength. However, increasing the amount of lime proved to be feasible only to improve texture. © 2012 Taylor & Francis Group.

Optical Fiber Relative Humidity Sensor Based on a FBG with a Di-Ureasil Coating

In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0-95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures.

Estudo teórico e experimental das ligações diretas contra-fiadas entre paredes de blocos de concreto em escala real e reduzida 1:4

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo experimental de vigas de alvenaria estrutural sujeitas à flexão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência à compressão da alvenaria estrutural

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do graute e da taxa de armadura no comportamento da alvenaria de blocos de concreto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Desenvolvimento das técnicas de produção de blocos de concreto para alvenaria estrutural na escala (1:4)

Pós-graduação em Engenharia Civil - FEIS

Análise do comportamento experimental e numérico de prismas de alvenaria estrutural submetidos a ações verticais utilizando elementos finitos volumétricos

Pós-graduação em Engenharia Civil - FEIS

Análise teórica e experimental do comportamento de vigas de alvenaria estrutural armada sujeitas à flexão simples

Pós-graduação em Engenharia Civil - FEIS

Análise experimental da conexão entre blocos segmentais e geogrelha de PVA

The test system connection segmental blocks and geogrids at the Department of Civil Engineering, UNESP - Guaratinguetá order to verify the strength of the connection system when subjected to different confining stresses. The present work aims to demonstrate the procedures for carrying out the test as well as the placement of concrete blocks. Were analyzed two ways of placing the blocks in the press. An entire block and two halves in the first layer, named position 12, compared to a different format, two entire blocks in the first layer, named position 21; also geogrids: single and double layer. From the data obtained for the peak strength of 20 tests it was possible to obtain the envelopes break in the connection for single and double layer. In 2011, the size of the concrete block used in the test was lower when compared with previous years. What resulted in significant decreases in the loss of connection in single layer and it was noted that there was no decrease in the strength of connection in the double-layer tests, despite the smaller area of contact between the block and geogrid. It is concluded that, through the analysis of geogrids after running the test, the concrete block is responsible for theforce that allows the movement of the geogrid due to the force from the ground

Análise de blocos de concreto com resíduo de borracha de pneu e metacaulim

Pós-graduação em Engenharia Civil - FEIS

Viabilidade técnica e econômica do superadobe na construção de casas populares

The need for affordable housing and the high cost of today's building materials make necessary to look for useful and affordable technologies for these house buildings. In this context, this study aimed to evaluate the technical and economic feasibility of construction technology called Earthbag for use in public housing. Technical assessments were based on Kiffmeyer and Hunter's book (2004), academics dissertations and construction standards for the technology. The result allowed a positive evaluation towards the feasibility proposal and showing the possibility of replace the use of structural concrete blocks in public housing. The economic viability was performed an economical compared to a project Housing Project Bom Retiro 2 with one of Earthbag which have been shown considerable savings between the techniques. For the construction of masonry, build with purchased sand, 13% lower budget was found in comparison of a concrete masonry block. With the use of sand from the work site itself, there is a saving of 18%. Although earthbag has proven to be a technically and economically feasible for application in the construction of affordable housing, the shortage of technical and scientific studies and Brazilian regulations on this technology has limited its large-scale use