César Porras-Amores

Estimation of construction and demolition waste volume generation in new residential buildings in Spain

The management planning of construction and demolition (C&D) waste uses a single indicator which does not provide enough detailed information. Therefore the determination and implementation of other innovative and precise indicators should be determined. The aim of this research work is to improve existing C&D waste quantification tools in the construction of new residential buildings in Spain. For this purpose, several housing projects were studied to determine an estimation of C&D waste generated during their construction process. This paper determines the values of three indicators to estimate the generation of C&D waste in new residential buildings in Spain, itemizing types of waste and construction stages. The inclusion of two more accurate indicators, in addition to the global one commonly in use, provides a significant improvement in C&D waste quantification tools and management planning.

Assessing the potential use of strategies independent from the architectural design to achieve efficient ventilation: A Spanish case study

Increasing building tightness is one of the measures taken by the construction industry to reduce energy losses, but leading to unhealthy environments. Efficient ventilation strategies with low energy consumption are necessary in order to design and improve the existing forced ventilation systems. This paper assesses the potential use of different strategies, independently from the architectural design, to achieve efficient ventilation. To this end, the airflow pattern and the age of air have been assessed in an en suite bedroom within a Spanish house with the use of computational fluid dynamics predictions. The computational fluid dynamics model predictions were validated by the comparison against experimental measurements, with good agreement. An alternative ventilation strategy is proposed, not affecting the architectural design of the room. Statistical analysis is used to assess and compare the results obtained for the different cases simulated. Results show that although the room has a forced ventilation system, air stagnates and ventilation are not homogeneous. Statistical analysis shows that this strategy produces a significant impact on indoor air quality, particularly in bedroom areas where air tends to stagnate. Practical application: The Spanish Building Code provides a minimum level of air quality within the buildings although it does not ensure an efficient design of the ventilation system, being necessary the use of guidelines or other recommendations to advise the designers in order to achieve efficient ventilation designs. Implementation of strategies independent from the architectural design, as studied in this work, can improve the indoor air quality and therefore reduce the global building energy consumption. In addition, these solutions are recommended for construction works requiring quick-easy implementation without disturbing the inhabitants of a house and allowing the normal use of the building during the refurbishment works.

Analysis of the Relationship between Density and Mechanical Strength of Lightened Gypsums: Proposal for a Coefficient of Lightening

This article develops a relationship between the reduction of density in lightened gypsum and the addition of expanded and/or extruded polystyrene waste from the construction sector and their mechanical behavior. The equations determined in this study allow us to know the flexural and compressive strengths of a lightened gypsum/plaster compound once its density is known. The results show that there is an exponential relationship between the density of the compound and its strength. The methodology followed included a compilation of the results obtained in previous research works on lightweight gypsums, analyzing the relationship between density and mechanical strength and comparing them with the equations developed in this research. The results obtained by previous researchers have a good adjustment with the proposed models, and only perlite compounds present greater deviations in the compressive strength analysis. Also, a dimensionless lightening coefficient is defined which can help to determine the best application for a lightweight gypsum compound, comparing it with an ideal lightweight gypsum.