ABSTRACT
The investigation reported in this paper is an evaluation of the mechanical behavior of full-scale ecological mortar slabs manufactured with a mixture of expanded clay and recycled concrete aggregates. The composite mortars form a compressive layer over laminated wooden joists to form a single construction unit. To do so, full-scale flexural tests are conducted of the composite laminated wood-ecological mortar slabs with different types of mortar designs: reference mortar (MR), lightweight mortar dosed with recycled concrete aggregates (MLC), and lightweight mortar dosed with recycled mixed aggregates (MLM). The test results showed that the mortar forming the compression layer and the laminated wooden joists worked in unison and withstood a higher maximum failure load under flexion than the failure load of the wooden joists in isolation. Moreover, the laboratory test results were compared with the simulated values of the theoretical model, generated in accordance with the technical specifications for structural calculations contained in the Spanish building code, and with the results calculated by a computer software package. From the analysis of the results of the calculation methods and the full-scale laboratory test results, it was concluded that the safety margin yielded by the calculations validated the use of those methods on this type of composite slab. In this way, a strong mixed wood-mortar slab was designed, contributing little dead-load to the building structure and its manufacture with recycled aggregate, also contributes to the circular economy of construction materials.
ABSTRACT
The properties and the behaviour of plaster mortars designed with Polyurethane Foam Waste (PFW) are studied in this investigation. A characterization of the mixtures is completed, in accordance with the technical specifications of European Norms. The incorporation of polyurethane waste foam can yield porous and lighter mortars, with better resistance to water-vapour permeability, although with weaker mechanical strength and higher levels of absorbency. Nevertheless, suitable mechanical strengths were achieved, resulting in a new material that is compliant with the requirements of the construction industry. The use of PFW in the the manufacture of gypsum mortars for construction reduces the consumption of natural resources and, at the same time, recovers an industrial waste that is otherwise difficult to recycle.
ABSTRACT
The degree of compliance with the RegistrodeEmpresasAcreditadas (REA) (Registry of Accredited Companies) and its implementation by the Public Administrations in Spain is compared with its implementation among private construction sector firms. The Registry of Accredited Companies is a tool for risk-prevention control that is defined by Law 32/2006 in Regulation of Subcontracting in the Construction Sector in Spain. On the basis of a quantitative analysis of the data obtained from public bodies registered with the REA, the study is limited to AyuntamientosyDiputacionesProvinciales (Municipal Town and City Councils and Provincial Councils of the Provincial Government). To do so, the registration records with the REA of both public administrations are analyzed within the 50 Provinces and the two Autonomous Cities that together constitute the 17 Autonomous Communities of the national territory of Spain. In parallel, a comparative study is performed of the registration records of private construction sector firms registered with the REA. Public digital data-management tools are used for the investigation, together with publicly available information known as the RelacióndePuestosdeTrabajo (RPT) (List of Employment Positions) of the corresponding public entities under analysis, with the objective of testing the information and validating its degree of reliability. Likewise, a survey is administered to gather data on the registration of private construction center firms, in addition to the use of the qualitative Focus Groups technique, so as to assure the reliability the survey data. The results revealed unequal treatment by the Labor Authority with regard to the imposition of similar administrative obligations. A clearly negative discrimination was noted with regard to private construction sector firms, in comparison with the permissive attitude and light administrative burden of the Public Administrations.
