Purpose – The traditional models of real estate market have several sources of imprecision, such as transitions between submarkets, generating difficulties in property valuation. The purpose of this paper is to examine an alternative to improve mass appraisal models, using fuzzy rules. Design/methodology/approach – Fuzzy rule-based systems (FRBS) are able to generate flexible systems and may be useful in considering vagueness or imprecision presents in real estate market. An application to the housing market of Porto Alegre (Brazil), with more than 30,000 apartments, transacted in 1998-2001, illustrates the fuzzy system, comparing with traditional hedonic regression model. Findings – The results have indicated the potential of fuzzy rules to use in mass appraisal. Originality/value – This paper presents a procedure to develop mass appraisal models using FRBS.

The building industry is responsible for a large amount of waste, and the measurement and modelling of this waste could be used to develop better waste management plans. Several theoretical models explain the relationships between waste and building characteristics, but local practices may result in different behaviours. This study aimed to measure and analyse the waste generated through construction. It was based on the analysis of 18 building sites located in the region of Porto Alegre, Brazil. Waste was measured at these sites, and the results showed an average waste generation rate of 0.151 m³ m^-2. A regression analysis of the collected data presented a satisfactory performance in two models. The first model was developed to explain total waste generation, including the effects of certain attributes, with an R² = 0.81. The changes in waste generated during construction were estimated. The second model considered time schedules and examined the effect of the construction stage on waste generation, and reached an R² = 0.91. The model with time indicated an S-shaped relationship. The models presented satisfactory statistical parameters and could be used to produce better waste management plans in the preconstruction stage.

This paper presents an investigation about acoustic absorption of mortars with partial replacement of sand by waste (plywood formwork, rice husk, and thermoplastic shoe counters), examining different levels of replacement (0%, 5%, 10%, 25%, and 50%). The measurement of acoustic absorption was performed using a plane wave impedance tube with 100 mm diameter, using mortar samples of 20 mm, in frequency range 200-2000 Hz. Results demonstrated that some composite with waste presented noise reduction coefficient (NRC) above the reference mortar (NRC = 0.0343), such as a composite with 50% rice husk (NRC = 0.2757) and other with 50% of plywood waste (NRC = 0.2052). Since there is virtually no cost or difficulty to use these residuals, it may be concluded that it is a sustainable alternative to improve the acoustic comfort and reduce the impact of the waste on the environment.