The Use of Sargassum spp. Ashes Like a Raw Material for Mortar Production: Composite Performance and Environmental Outlook

The accumulation of brown algae from the genus Sargassum has been increasing over the years in coastal regions of the Caribbean, Africa, Brazil, and Mexico. This causes harmful effects to the ecosystem, human health, the economy, and the climate due to gas emissions from its decomposition process. There is the possibility of this biomass being reused in civil construction, and some studies have been carried out on its application to common Portland cement mortar. As such, the objective of this study is to evaluate the potential of sargassum ash as a mineral addition to partially replace fine aggregates in Portland cement mortar. Characterization of the raw materials was carried out through X-ray fluorescence spectroscopy, loss on ignition, particle size distribution, Brunauer-Emmett-Teller (BET) analysis, real density, X-ray diffraction, scanning electron microscopy, and dispersion spectroscopy of electrons. The mortars were prepared by partially replacing the fine aggregate (sand) with sargassum ash at 0%, 5%, 10%, and 20%. Mortar performance was evaluated through water absorption, apparent porosity, apparent specific mass, and compressive strength 7, 28, and 63 days after curing. Lastly, a life cycle assessment was conducted in accordance with ISO standards 14040:2006 and 14044:2006. The results showed that replacing sand with sargassum ash increases water absorption and apparent porosity, and decreases the apparent specific mass and compressive strength as replacement increases. Nevertheless, the compressive strength results after 63 days for 5 and 10% replacement did not differ statistically from reference values. The life cycle assessment indicated that mortars with partial replacement of sand by sargassum ash show positive environmental impacts when compared to reference values for most categories, regardless of the scenario analyzed, especially for mortar with 10% replacement. As such, the use of sargassum ash at 10% does not alter the mortar's compressive strength values after 63 days, but does reduce its environmental impact. The application of this biomass in civil construction materials provides a destination for this algae, and that can be a solution to mitigate the social, environmental, and economic problems it has been causing.

Bibliometric and systemic review of the state of the art of occupational risk management in the construction industry

Objectives. The objective of this study is to use bibliometric and systemic terms to select and analyze a set of articles dealing with occupational risk management in the civil construction industry. Methods. Knowledge development process - constructivist (ProKnow-C) methodology was used as an intervention instrument to guide the selection of the bibliographic portfolio and to support systemic analysis. Results. The bibliographic portfolio was created and included 20 articles. Bibliometric highlights were relevant articles, authors, countries of origin, journals and keywords. Systemic analysis showed opportunities to contribute to the state of the art in all areas of knowledge, enabling the researcher to understand theoretical bases, gaps and research opportunities for the theme and thus establish their research question in accordance with the established knowledge vision. Conclusions. The systemic analysis of each article in the bibliographic portfolio based on the decision support model and areas of knowledge present in each stage of its construction measures the amplitude of the knowledge at each stage, and therefore the completeness of or gaps in each article. This clarifies the overall state of and gaps in the field, showing opportunities for new research.

Performance Analysis of High-Performance Concrete Materials in Civil Construction

This paper develops the mechanical and durable samples of C50 high-performance concrete, studies the mechanical properties, crack resistance, sulfate attack resistance, frost resistance, and impermeability of concrete with different mineral admixtures of mineral powder and fly ash, and obtains the best mineral admixture of mineral powder and fly ash to improve the performance of high-performance concrete. The results show that the doping effect is the best when the ratio of prepared mineral powder to fly ash is 3:2. With the increase in the mineral powder-fly ash admixture, the slump and expansion of high-performance concrete decrease rapidly at first and then slowly. In total, 60% doping is the turning point; the compressive and flexural strengths of concrete decreased slowly at first and then rapidly. Taking 30% of the admixture as the turning point, 35% of the mineral powder fly ash is generally selected. By mixing and adding a certain proportion of fly ash and mineral powder admixtures, the crack resistance of concrete is enhanced, and the shrinkage and cracking are reduced. The corrosion resistance coefficient will exceed 88%, the relative dynamic elastic modulus will exceed 95%, and the impermeability grade will reach P17. The durability of concrete can be improved by adding mineral admixtures.

Manufacture and Characterization of Polypropylene (PP) and High-Density Polyethylene (HDPE) Blocks for Potential Use as Masonry Component in Civil Construction

The lack of suitable destinations for plastics materials can be a global environmental problem. The alternative use of materials for sustainable construction encourages the standardization of waste and promotes effective social, environmental and economic gains at the local level and ensures savings and income for communities. The aim of this paper is the development, manufacture, and characterization of PP and HDPE recycled polyolefin blocks as masonry components in civil construction. These blocks were manufactured by the rotational molding process. Besides this, the mechanical, physical, impact and flammability properties of the blocks were studied. In conclusion, HDPE showed better behavior than PP in tests realized.

Absenteeism of people with disabilities in the construction industry in Brazil

BACKGROUND

The employment rates of people with disabilities (PWDs) are lower than the general population in many countries because of several factors, including prejudices about labour production and absenteeism of these workers.

OBJECTIVE

The objective of the research was to evaluate the absenteeism of PWDs in the construction industry in the metropolitan area of Recife, Pernambuco, Brazil.

METHODS

Study participants were workers with disabilities that performed jobs at the work sites in the construction industry. Participants were interviewed and they answered the Work Limitation Questionnaire (WLQ). In order to compare the absenteeism of people with disabilities and without disabilities, the companies provided real absenteeism data.

RESULTS

Twenty-five workers with disabilities participated in the study, of which 32% were laborers and 72% had physical disabilities. The companies made accommodations for 56% of PWDs and all of them were the organizational type. The WLQ summed score of the PWDs was 3.16. The mean absenteeism of the PWDs was 19.00% ±1.22 standard deviation (SD) (p = 0.238) higher in relation to workers without disabilities.

CONCLUSIONS

Most of the workers with disabilities had lower absenteeism than those without disability, however, the mean absenteeism of PWDs was higher in relation to workers without disabilities. In addition, workers higher educational level, the laborer of auxiliary warehouse, the workers for whom the companies have not made accommodations to the workplace and the higher WLQ summed score lower statistically significantly absenteeism in relation to workers without disabilities.