A. Moragues

THE USE OF A GEOGRAPHICAL INFORMATION SYSTEM TO ASSESS THE EFFECT OF TRAFFIC POLLUTION

The construction of a new section of the M-40 ring road will give rise to a redistribution of traffic in the city of Madrid and its outskirts. The use of a geographical information system (GIS) has provided a suitable instrument for assessing and locating traffic effects before and after the new infrastructure enters service. Traffic information was used as basic input data for drawing up a pollution map, taking a standard day with unchanging weather conditions. The model chosen used several parameters to compute the concentrations of pollutants at ground level. Finally, the pollution map was cross-referenced with the standard maps in order to locate and quantify the population affected by the different pollution levels and the wildlife and historic and/or archaeological features at risk. The assessment was made before and after construction of the new road. The utilization of GIS methodology allowed the environmental changes to be automatically located with the use of a personal computer. This proved to be an effective tool for carrying out environmental impact assessments.

Polypropylene-fibre-reinforced mortar mixes: Optimization to control plastic shrinkage

Volume changes which occur as a newly cast mortar is exposed to drying conditions will result in tensile stresses and lead to cracking of the mortar and concrete at early ages. Because of the growing interest in predicting the tensile shrinkage stresses that give rise to cracking in concrete, and the increasing use of polypropylene-fibre-reinforced cementitious materials, this research has been carried out to investigate how mix proportions influence the plastic shrinkage of polypropylene-fibre-reinforced mortars. This paper describes an experimental approach to the problem, which was intended to investigate the optimization of polypropylene-fibre-reinforced mortar mixes in order to minimize plastic shrinkage. The method selected is based on factorial design of experiments in which the parameters considered are the cement/sand and water/cement ratios and the polypropylene fibre content. The test results indicate that polypropylene fibres added to mortars reduce the plastic shrinkage. As a first result, a mathematical equation which allows prediction of the plastic shrinkage as a function of the mix design is given.

A testing method for measuring plastic shrinkage in polypropylene fibre reinforced mortars

The use of concretes reinforced with a low volume of polypropylene fibres added as secondary reinforcement, mainly to control cracking due to plastic shrinkage at early stages is of recent interest. In this paper, a method for measuring plastic shrinkage of mortars is proposed. The influence of the water/cement ratio, cement/sand ratio and amount of polypropylene fibres on the plastic shrinkage of mortars is also studied. The method presented in this paper gives information about the quality of the material studied in terms of plastic shrinkage and potential cracking.

Seasonal analysis of air pollution levels in Madrid.

Madrid city has a high density of population and suffers from chronic congestion problems. It means that some pollutants could produce atmospheric emergency situations when weather stability periods last longer. Due to the low level of industry in the region, mobile sources have an important contribution to total emissions. Madrid has a 20-year-old air pollution control network which is composed of 24 permanent stations which control all pollutants and atmospheric variables. This paper analyses inmission values from 1990 to 1997. The analysis covers main pollutant values and their variations within the week and between seasons. The study has a twofold approach: mean-daily values and semi-hourly values. The results allow to draw some conclusions about inmission values in different areas of the city and how traffic-flow contributes to them.

Measurement of the degraded depth in cementitious materials by automatic digital image processing

The combination of a staining method and an automatic digital image-processing algorithm is presented here, to measure degradation depths in cementitious materials. The measurement of those degraded depths is usually made by direct visual measurements, resulting in many errors and low reproducibility. The automatic digital image analysis (ADIA) method proposed here is mainly based on the differentiation of the degraded zone and the sound zone on the basis of the image histogram. The method comprises several steps, such as sample alignment, image calibration, background subtraction, image filtering, automatic segmentation and final measurement of the degraded depth. The algorithm developed has been used to measure the degraded depths of a set of decalcified cement mortars, made from different cement types and with varying w/b ratios. Relative to previous methods, this automatic procedure improves the precision (about 0.03 mm) and the statistical representation of the measurements. The results obtained by ADIA were compared with direct visual measurements with a very good correlation (R2 = 0.96) and a mean error of 6%.

Model for predicting plastic shrinkage of polypropylene reinforced mortars

There is increasing interest in the use of concretes reinforced with a low volume of polypropylene fibres added as secondary reinforcement, mainly to control cracking due to plastic shrinkage at an early age. This paper discusses the influence of water-cement ratio, cement-sand ratio and amount of polypropylene fibres in the plastic shrinkage of mortars. A prediction method, based on a factorial design of experiments, is also proposed.

Viability Study of a Safe Method for Health to Prepare Cement Pastes with Simultaneous Nanometric Functional Additions

The use of a mixing method based on a novel dry dispersion procedure that enables a proper mixing of simultaneous nanometric functional additions while avoiding the health risks derived from the exposure to nanoparticles is reported and compared with a common manual mixing in this work. Such a dry dispersion method allows a greater workability by avoiding problems associated with the dispersion of the particles. The two mixing methods have been used to prepare Portland cement CEM I 52.5R pastes with additions of nano-ZnO with bactericide properties and micro- or nanopozzolanic SiO2. The hydration process performed by both mixing methods is compared in order to determine the efficiency of using the method. The hydration analysis of these cement pastes is carried out at different ages (from one to twenty-eight days) by means of differential thermal analysis and thermogravimetry (DTA-TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analyses. Regardless of composition, all the mixtures of cement pastes obtained by the novel dispersion method showed a higher retardation of cement hydration at intermediate ages which did not occur at higher ages. In agreement with the resulting hydration behaviour, the use of this new dispersion method makes it possible to prepare homogeneous cement pastes with simultaneous functional nanoparticles which are physically supported on the larger particles of cement, avoiding exposure to the nanoparticles and therefore minimizing health risks. Manual mixing of cement-based materials with simultaneous nanometric functional nanoparticles on a large scale would make it difficult to obtain a homogenous material together with the health risks derived from the handling of nanoparticles.

Analysis of the impact of the Arganda metro line on alternative road route emission levels

Abstract The object of the present work was to carry out the environmental assessment of a new metro line in Madrid by means of an emission model using a down – up methodology, calculation parameters of which were taken from the European Union-sponsored programmes CORINAIR 99 and COPERT 2000. The study assesses emissions over different time horizons, taking into account the resulting variations in traffic speed and intensity upon the opening of the new infrastructure. The results obtained show that the construction of the line has led to a significant reduction in the various pollutant emission levels, particularly in the areas closer to the city. The most significant reductions are expected to be even greater in future scenarios.

Health effects associated with Madrid air pollution levels

The purpose of this study was to determine the relationship between the pollution levels recorded in Madrid and the number of hospital admissions made on the grounds of respiratory disorders.