cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14287028
title: Influence of the content and dispersion of limestone fines in the bond strength of mortar-brick interfaces

description: Abstract This study investigates the effects of the content and dispersion of limestone fine particles on the bond strength of mortar-brick interfaces. Mortars with 0%, 30% and 60% replacement of binder by limestone fines with a particle size distribution lower than cement. We also evaluated particle dispersion by adding 0.02% polycarboxylate-based dispersing admixture to the mortars applied on the surfaces of clay bricks treated with a water repellent. The rheological behavior of the mortars varied depending on the particle size of the limestone fines used and the admixture added, measured by a rotational rheometer. Despite a reduction in the mechanical properties, the 60% replacement of of binder by limestone fines, associated with the use of dispersing admixture can increase the bond strength of the mortar-brick interface by 76%. The increased adherence can be explained by the increased area or contact between substrate and mortar. The conclusion has practical implications, as it demonstrates that is possible to reduce the amount of matrix binder without changing bond strength.
DOI: 10.6084/m9.figshare.14287027
title: Surface chemical modification of sponge gourd fiber aiming at compatibility and application as reinforcement in cementitious matrix

description: Abstract This paper discusses the esterification of sponge gourd fibres (Luffa cilyndrica) to reinforce the cementitious matrix. The esterification reactions were performed with the modifying agents octanoyl chloride, lauroyl chloride and stearoyl chloride, using toluene as solvent and pyridine as catalyst. The fibres were characterised through tensile tests, scanning electron microscopy (SEM) and moisture absorption. Composites were produced with untreated and treated fibres with octanoyl chloride, which yielded the best results, with a 65% reduction in moisture absorption, 40% in tensile strength and 67% increase in the elasticity modulus. The results of the composites bending test indicated that a toughness of 0.70 kJ/m2 did not change significantly and there was an increase of about 20% in the rupture modulus (6.64 MPa) and the elasticity modulus (15.10 GPa) of the composites reinforced with treated fibres compared with those reinforced with untreated fibres. The best mechanical properties of the composites with treated fibres indicate that the proposed treatment may have improved the performance of sponge gourd fibres as a reinforcement of the cementitious matrix.
DOI: 10.6084/m9.figshare.14287026
title: Evaluation of the addition of sugarcane bagasse ashes in mixed mortars

description: Abstract The aim of this paper is to analyze the effect of addition of sugarcane bagasse ashes (SCBA) in mixed mortars utilizing a 1:2:9 mix proportion by volume for cement, lime and fine aggregate. The ashes were characterized by its particle distribution, pozzolanic activity, chemical composition, bulk density, moisture content and loss on ignition. Then the mortars were produced with a constant water/cement ratio of 2.64 and a partial replacement of sand with sugarcane bagasse heavy ash using different substitution percentages (0%, 5%, 10%, 15% and 20%). Among these was selected a trace, considering that its features have not undergone significant downsides to the 7.5% replacement of cement by fly ash. The mortars were characterized in the plastic state: water retention, bulk density and air content, and in the hardened state: capillary coefficient, tensile strength by bending test, axial compressive strength and flexural and longitudinal Young's modulus. Thus results analysis showed that the ashes can be incorporated into mortars without causing significant alterations in its properties.
DOI: 10.6084/m9.figshare.14287022
title: What are the main organizational characteristics of companies in the different sectors of the civil construction?

description: Abstract The authors´ aim was to identify the factors that define the main organizational characteristics among the companies of the civil construction subsector which are located in the city of Curitiba and its metropolitan area, Brazil, as well as to verify the existing differences between the five most relevant activity segments of this market, i.e. residential, industrial and commercial, infrastructure, specialized services, and industrial construction. For this purpose, an applied, exploratory, and quantitative research was developed, at Master´s level. The Survey Method was selected as the main procedure for this study, allowing the retrieval of primary data through the application of a questionnaire in a group of 118 companies. The questionnaire aimed at identifying the profile of the organization and the organizational characteristics of the assessed companies. Data were analyzed through inferential statistics by applying multivariate techniques of factor analysis and discriminant analysis. The factor analysis highlighted the improvement strategies, the individual's behavior at work, the organizational structure, the dynamics of growth, management style, interpersonal relationships and the company´s orientation towards the market, as key factors. The discriminant analysis showed significant organizational development homogeneity for the companies representing the different sectors of activity.
DOI: 10.6084/m9.figshare.14287019
title: Dry cost concretes produced with density-separated-crushed-CDW recycled aggregates

description: AbstractThe use of construction and demolition waste (CDW) in the production of dry cost concrete blocks harmonizes CDW recycled aggregates' characteristics with the different levels of mechanical requirements in use. At the same time, dry cost concretes are scarcely studied due to the difficulty to simulate industrial pressing energy in lab scale; however, that limitation can be partly overcome by using a lab scale compressive testing machine with elongation control, which also allows determining the mixtures' behaviour. The aim of this paper is to evaluate the fresh and hardened state of dry concrete produced with mixed CDW aggregates (with or without the use of density separation), by a lab-scale testing machine. Structural dry concrete can be obtained through the full substitution of the natural aggregates by density-separated-crushed-CDW recycled aggregates. The compressive strengths achieved are similar to those obtained by a reference dry concrete (produced with natural aggregates). The influence of the aggregates' characteristics and their dry mixes (cement; aggregates) was identified through a lab-scale compaction technique. The most important parameters to increase concrete compressive strength are the porosity reduction of recycled aggregates and granulometric optimization of dry mixes.
DOI: 10.6084/m9.figshare.14287016
title: Construction delays: a case study in the Brazilian Amazon

description: Abstract he construction industry is one of the industrial sectors with the lowest rates of fulfilment of contract deadlines, especially in developing countries. This fact has been the focus of considerable discussions seeking to identify the causes of the delays. The main purpose of this paper is to use factor analysis to identify the factors that are correlated with delay, contemplating exclusively residential real estate projects and using a city in the Brazilian Amazon as a case study. Based on the database from the government agency that authorises constructions in the city of Belém (City Planning Department - Secretaria Municipal de Urbanismo, SEURB) and data from construction companies, the study investigated 274 construction projects from the past 11 years. Factor analysis and work with the variables that can be identified and measured in the initial phase of the project, i.e., during the feasibility study, demonstrate that the physical characteristics of the apartments and the construction project are the primary causes for variations in construction delays; these causes have not yet been reported in the literature. We hope that the results of this study will contribute to more consistent forecasting of construction time, minimising the risk of delays.
DOI: 10.6084/m9.figshare.14287013
title: Environmental assessment of the life cycle of cementitius roofing sheets with asbestos fibers or with polypropylene fibers

description: Abstract The aim of this study is to evaluate the life cycle of cementitious roofing sheets manufactured with asbestos fibres or with polypropylene fibres. The Life Cycle Assessment (LCA) technique and the Assessment of Aspects and Environmental Impacts (AAIE) technique were applied to make a comparative analysis of the environmental impacts caused. In the LCA technique, the atmospheric emissions that cause the greenhouse effect, acid rain and emissions with human toxicity potential, as well as the consumption of resources (water and energy) were determined for all the stages of the life cycle. In the AAIE technique, the impacts on the use of natural resources and the health risks due the carcinogen factors of the constituent materials of the roofing sheets were added to the LCA assessment. Two scenarios were then evaluated, in which the raw material extraction location, the location of the construction site where the roof sheets would be used and the destination of the waste after its life cycle were fixed, but the production locations varied. As a final result, the scenario with polypropylene fibres had a better evaluation in four out of the seven categories analysed. Thus, this study confirms that, from an environmental perspective, the use of asbestos fibres is more unfavourable than the use of polypropylene fibres.
DOI: 10.6084/m9.figshare.14287011
title: Impact of the envelope on residential heating energy demand in the Metropolitan Region of La Plata, based on the energy retrofit of a house

description: Abstract The metropolitan area of La Plata, Argentina, represents 1.6% of households in Argentina. Based on the analysis of the energy retrofit of a house, we provide indicators in order to propose a methodology that facilitates the extrapolation, at regional level, of the impact of a general energy retrofit in homes. The results obtained are presented from micro to macro level, in context of energy shortage and recurrent crisis in the supply of fuels and electricity in Argentina. The improved thermal resistance of walls and ceilings throughout the residential park of La Plata lead to a reduction of 12% of the energy consumed in heating, and a saving of 30,000 TEP / year. We conclude that the incidence of additional insulation on the cost of building justifies its use, partially solving the lack of fuel in our country, reducing fixed costs in housing, providing thermal comfort to users and generating economic reactivation of the construction sector.
DOI: 10.6084/m9.figshare.14287009
title: Parametric analysis of solar chimneys aiming at performance optimization in typical climates of the Brazilian territory

description: Abstract Natural ventilation is one of the main strategies used for the passive cooling of buildings, powered by wind forces or by stack effect. The second choice is more effective in locations where obstacles induce low wind speed, as it is the case in urban environments, for example. This paper analyses the potential of solar chimneys to promote natural ventilation in low-rise buildings in typical climates of the Brazilian territory. For this purpose, this study analysed variations in geometric and constructive parameters in cities representing each of the Brazilian climate zones. Those parameters included air channel depth, chimney length, solar collector tilt and type of glass used in the solar collector. The study also included a comparative analysis of solar chimneys with and without a solar collector, both with the same geometric configuration. The results obtained show the potential of solar chimneys to promote natural ventilation in the cities analysed, and enabled the identification of the parameters and values that optimize the performance of the set in each case.
DOI: 10.6084/m9.figshare.14287007
title: Discussion of a passive house envelope's performance adaptaded to Bioclimatic Zone 2 according to the RTQ-R

description: Abstract The building sector's high energy consumption and the consequent emissions of greenhouse gases has led the European Union to publish, in 2010, the 2010/31/EU Directive, determining that by the end of 2020 all new buildings should be nearly Zero Energy Buildings (nZEB). One possible way to achieve this goal is the implementation of the Passive House concept. The aim of this paper is to analyse the efficiency level of the envelope of a Passive House through using the simulation method RTQ-R (Technical Code of the Quality of the Energy Efficiency Level of Residential Buildings). The analysis is performed for the building according to the code's assumptions (naturally ventilated and artificially air conditioned), and using a mechanical ventilation system with heat recovery capacity (MVHR). Firstly, the building was classified as level B, due to the air conditioner's high consumption for heating, and, when using the MVHR system, the building was classified as Level A. In a comparative analysis of energy consumption, the system showed an economy of 56.63% for the MVHR when compared with the air conditioning system. Thus, this study has proven the success of the application of the Passive House concept for bioclimatic zone 2 (ZB2).
DOI: 10.6084/m9.figshare.14287004
title: Photometric analysis and characterization of a transition space illuminated with daylight: its implications for functional visión

description: In sunny climates, Transition Spaces may place excessive demands on the human eye and become real functional vision barriers, since building morphology is influenced by the dynamics of daylight. In this study, we describe the lighting characterization of a case study located in the city of Mendoza, analysing different lighting magnitudes and their relation to the standards regulating lighting and visual tasks in this type of building. The results showed that the lighting conditions of the transition space analysed, do not achieve the values recommended by the current standards, with lighting conditions that prevent the adequate performance of visual tasks, such as face recognition, highlighting the need to review the design requirements for this type of space, mainly regarding aspects related to daylighting modeling.
DOI: 10.6084/m9.figshare.14287003
title: Urban forestation project as the city's heritage

description: Urban forestation is a crucially important element for the quality of the urban space, contributing also to the formation of the memory and cultural heritage of cities. Landscape design can ensure special characteristics of significant aesthetic value to the city. This study analysed the group of trees lining the streets of the city of Maringá-PR present in its initial master plan, implemented based on an urban forestation concept concept that has great aesthetic appeal. This study was divided into four stages: i) simulation of the city's initial urban forestation plan by mapping the distribution of individual types of trees planted along the streets in the study area; ii) analysis of the current landscape conducted in loco and photographically recorded, identifying the present situation of the group of trees along the streets; iii) comparative analysis of the urban forestation project originally implemented and the present condition of the trees, identifying the main factors influencing the development and preservation of the trees; and, finally, iv) proposing a re-forestation project. This project aims to solve the problems caused mainly by the aging of specimens, which has resulted in the need to replace old trees and preserve the aesthetic characteristics of the landscape established by the totality of the tree groups planted.
DOI: 10.6084/m9.figshare.14287001
title: Microclimatic analysis of a historic building in temperate climate: target range for the proper conservation of the materials

description: Despite the recognised importance of microclimatic studies in historic buildings for the proper conservation of their collections and of historically and culturally important objects, knowledge about their behaviour in temperate climates is still limited. The past decades have seen the emergence of different specifications focused on the hygrothermal needs of materials. A dynamic approach, based on historical microclimates, has generated consensus among experts as a means to achieve sustainable ranges of temperature and relative humidity. This study aimed to classify the interior microclimate of a historic building in a temperate climate – St. Christopher church, Lisbon –, in order to verify the quality of the microclimate for the proper conservation of materials and to evaluate possible changes. For this purpose, a continuous monitoring system was used between November 2011 and August 2013, with several sensors measuring temperature and relative humidity recording every 10 minutes. The microclimate was classified in accordance with an ASHRAE specification – Handbook HVAC Applications, Chapter 21: Museums, galleries, archives and libraries. The high natural climatic stability verified does not justify the implementation of HVAC systems.
DOI: 10.6084/m9.figshare.14286995
title: Cost and time overrun in construction projects: categorization and influencing factors

description: Cost and time overruns are recurrent challenges in construction projects. This article aims to systematically review the literature on cost and time overruns in construction projects in order to categorize and identify the influence factors that cause such overruns. A systematic literature review (SLR) was carried out in a methodical fashion to ensure it is repeatable and can be scrutinised. Relevant information was extracted from the selected articles and subsequently synthetized in order to categorise and identify the influence factors, which trigger time and cost overruns. Nine categories were identified and defined on the basis of their determinants: governmental relations; contracts; organization; management; financing; design and documentation; scope changes; environmental and economic and activities and equipment. Moreover, 95 influencing factors were identified and classified into different categories. While the literature differs with regards to different situations and global regions, complicating the RSL process, there is considerable support for these factors. Evidence scarcity was detected in Latin America, particularly in Brazil. The literature on time and cost overruns in construction is contrasting, with 92 articles from 46 different reference sources from 1985 to 2014. Most of the research focused on specific influence factors, while this study categorised and synthesised them in order to provide a novel and broader perspective of the phenomenon.
DOI: 10.6084/m9.figshare.14286993
title: Cementitious composites strengthened with pure eucalyptus fiber and treated with tetraethyl ortosilicate (TEOS 98%)

description: This paper presents the attainment of higher flexibility and elasticity in a high initial strength (CPV) Portland cement matrix, achieved through the addition of pure eucalyptus fibers treated with tetraethylorthosilicate TEOS 98%. The fibers used were characterized by their morphology through optical microscopy and through the use of anatomic MIPRO software; its water absorption properties were analysed using the TEOS 98% impregnation efficiency test. In order to obtain the composites, cement masses were formulated with the addition of pure eucalyptus fibers and treated at concentrations of 2%, 5% and 10% by weight. The composites were characterised for water absorption, porosity, and modulus of elasticity (MOE), measuring their flexural strength at three points. A comparative analysis was done between the cement-eucayptus fiber composite and a high initial resistance Portland cement mass. The results showed that the highest valores de reforço were achieved in the cement with 2% eucalyptus fiber treated with 98% TEOS, since that cement presented the highest MOE values, presenting more fissure control and energy absorption after cement matrix fracture.
DOI: 10.6084/m9.figshare.14286989
title: Impact of the mixer and time of mixing on the properties of industrialized mortar

description: Abstract Industrialized rendering mortars usually employ additives in their formulations, most commonly air-entraining agents. In order to ensure quality and production scale, they are prepared in manufacturing units with precise control of the formulation and dosage of raw materials and additives. Despite the control in the production of this material in an industrial environment, variations in the mixing conditions may affect the level of air incorporation. On construction sites, mortars are usually either processed manually or with the use of mixing equipment. This study evaluates the impact of the type of equipment and mixing time on air incorporation in industrialized mortars and the effect on their properties after hardening. The results indicate that the incorporation of air results from the adjustment between the mixing equipment and the mortar formulation. Different sensibilities of mortars to the type of equipment have been identified. That fact indicates that an alternative to reduce variability on the level of air incorporation in building sites depends on the development of formulations with minimal sensibility to the mixing process.
DOI: 10.6084/m9.figshare.14286988
title: Nanomechanichal properties of synthetic calcium silicate hydrate

description: Abstract Calcium silicate hydrate (C-S-H), the main product from portland cement hydration, has a great influence on most physical and mechanical properties of cement based materials. However, until now, there are no structural models relating chemical composition, micro and nanostructure with its physical-chemical and mechanical properties. In this study, we used the technique of instrumented indentation to evaluate the nanomechanical properties of two synthetic C-S-H with different Ca/Si ratio. The results showed that it is possible to estimate with a good accuracy the elastic modulus and hardness using only 16 indented points, with several cycles of loading for each indentation, and that the intensity of the indentation load is not significant. It was also shown that the C-S-H elastic modulus increases when the Ca/Si ratio decreases, confirming the calculations based on field forces methods of Manzano et al. (2009). However it was found that micro and nanoporosity have a significant effect on the result. Finally, a discussion about some of the parameters to be controlled to modify the mechanical characteristics of the C-S-H gel produced by the portland cement hydration is presented.
DOI: 10.6084/m9.figshare.14286987
title: Porosity estimation of cement-lime mortar through the volume calculation method

description: Abstract The presence of lime in mixed mortars is responsible for the increase in the demand for mixing water for a given consistency. The additional water, which is not consumed in the cement hydration, remains free in the system and when evaporating it leads to high porosity in the hardened mortar. This paper presents the method of volume calculation as a tool for estimating the porosity of mixed mortars through their constituents, including lime, as well as its correlation with relevant properties in the hardened state. The method presented proved to be adequate for predicting the properties that define the behavior of the rendering. The data suggest that this approach needs further research, involving issues not considered in the theoretical volume calculation, such as the influence of shrinkage and carbonation.