Façade noise abatement prediction: New spectrum adaptation terms measured in field in different road and railway traffic conditions

The Façade Acoustic Insulation Index is one of the most disputed parameters for residential and non-residential buildings. The real performance of the façades does not often agree with the calculated one during the design stage. The field measurement sessions are usually carried out using pink noise spectra, as suggested by the International Standards ISO 717-1. In the present paper six mean spectra derived from in field measurements were proposed: urban toads, traffic lights, roundabouts, freeways, Highways, very high speed trains, high speed trains, and low speed trains. The proposed spectra were equalized against acoustic distortion and were used to measure the noise abatements in a terraced house and in a classroom façade. The highest abatements result for spectra with high levels at high frequencies, better absorbed than low ones by façade elements and frames. The spectrum adaptation terms were also calculated both for the standard and the proposed spectra and were used to predict the façade abatements in compliance with EN ISO 12354-3: the values C_j calculated from the proposed spectra provided more reliable results than the terms C and C_tr (ISO 717-1) and represent a useful tool to predict the noise façade abatements.     

Shedding light onto the spectra of lime: Raman and luminescence bands of CaO,Ca(OH)2 and CaCO3

In microscopy studies of 19^th‐century cement stone, we found free lime in the form of darkened spherical structures, as they were described in the literature already. When trying to determine their phase composition by Raman spectroscopy, we encountered contradictive assignments in literature spectra of the lime phases CaO, Ca(OH)₂ and CaCO₃ and observed strong spectral features that have been ignored or erroneously assigned so far. In this study we present Raman spectra of pure lime phases and of a naturally grown calcite crystal, burnt limestone (quick lime, mainly CaO), aged slaked lime putty (mainly Ca(OH)₂), and carbonated lime putty (mainly CaCO₃). Based on the results, we shed light mainly onto these two questions: (1) Does CaO have a Raman spectrum? (2) Which features in the spectra are luminescence bands that could be (and already have been) misinterpreted as Raman bands? We proof our assignment of luminescence bands in lime phases by using three different laser wavelengths for excitation, and give hypotheses on the origin of the luminescence as well as practical advices on how to identify these misleading features in Raman spectra. This article is mainly addressed to users of Raman spectroscopy in different fields of material analysis who might not be aware of the presence of interfering bands in their spectra. Copyright © 2014 John Wiley & Sons, Ltd.     

Analytical study of polychromy on exterior sculpted stone

A complete study on the remnants of the polychromy in the main entrance portal of Saint Paul's church (16th century, Úbeda, Spain) has been carried out using Raman microspectroscopy in combination with optical microscopy and scanning electron microscopy with energy dispersive X‐ray spectroscopy (SEM‐EDX). The polychromy in red areas showed the superposition of two well‐defined pictorial layers. The first one (probably original) was composed of cinnabar, red lead and hematite over a preparation coating containing calcite, gypsum and lead white. The second red pictorial layer was mainly constituted by cinnabar and was over a thicker preparation coating. Green samples showed a single pictorial layer over the weathered stone. The high fluorescence background made the examination of the latter samples extremely difficult by means of Raman microspectroscopy. SEM‐EDX detected abundance of copper and chlorine, and a detailed inspection of Raman spectra revealed the presence of a copper hydroxychloride, analogous to the naturally occurring mineral atacamite. Azurite remnants of the original polychromy were only found in the cracks of mortar joints. Alteration products like calcium and copper oxalates were also widely distributed in this layer. Copyright © 2009 John Wiley & Sons, Ltd.     

Hydration and carbonation of monoclinic C2S and C3S studied by Raman spectroscopy

We present a micro‐Raman study on the hydration and carbonation of the main silicate phases of Portland cement, i.e. monoclinic dicalcium silicate (C₂S) and monoclinic tricalcium silicate (C₃S). We investigate the reaction products and the loss of crystallinity induced by hydration on these two compounds. In the CO₂‐contaminated pastes we find that calcite, aragonite, and vaterite are inhomogeneously formed. We study sample cross sections to evaluate the maximum depth at which CaCO₃ is formed. We find that carbonation is limited to the first 500–1000 µm from the surface in the C₃S pastes, while in C₂S pastes CaCO₃ is formed well beyond this depth. Our results show the great potential of Raman spectroscopy in the study of the chemistry of cements. Copyright © 2006 John Wiley & Sons, Ltd.     

Use of micro‐Raman spectroscopy to study reaction kinetics in blended white cement pastes containing metakaolin

Curing temperature is known to play an important role in the formation, development, and stability of the hydrated phases appearing during pozzolanic reactions (chemical reaction between puzzolanic addition, metakaolin (MK), and calcium hydroxide from cement hydration). A typical example of this important reaction is to be found in metakaolin‐bearing cement pastes, characterized by hexagonal phases whose thermodynamic stability declines with rising temperature. These phases cannot be exhaustively researched with traditional techniques (such as X‐ray diffraction) due to their poor crystallinity. Consequently, micro‐Raman spectroscopy was used in the present study to explore the behavior of white cement paste blends containing 0, 10, and 25% MK at two curing temperatures (20 and 60 °C). This led to the identification, for the first time using Raman spectroscopy, of phases C₂ASH₈¹ (stratlingite) and C₃ASH₆, which appear in the MK–white cement reaction. The C S H gel formed was characterized by Q¹ dimers and a C/S ratio of 1.3–1.5. Raising the curing temperature favored the formation of C₄AH₁₃. Copyright © 2009 John Wiley & Sons, Ltd.     

Influence of loudspeaker directivity and measurement geometry on direct acoustic levels over façades for acoustic insulation tests with the International Standard ISO 140-5

The International Standard ISO 140-5 on field measurements of airborne sound insulation of façades establishes that the directivity of the measurement loudspeaker should be such that the variation in the local direct sound pressure level (ΔSPL) on the sample is ΔSPL < 5 dB (or ΔSPL < 10 dB for large façades). This condition is usually not very easy to accomplish nor is it easy to verify whether the loudspeaker produces such a uniform level. Direct sound pressure levels on the ISO standard façade essentially depend on the distance and directivity of the loudspeaker used. This paper presents a comprehensive analysis of the test geometry for measuring sound insulation and explains how the loudspeaker directivity, combined with distance, affects the acoustic level distribution on the façade.The first sections of the paper are focused on analysing the measurement geometry and its influence on the direct acoustic level variations on the façade. The most favourable and least favourable positions to minimise these direct acoustic level differences are found, and the angles covered by the façade in the reference system of the loudspeaker are also determined. Then, the maximum dimensions of the façade that meet the conditions of the ISO 140-5 standard are obtained for the ideal omnidirectional sound source and the piston radiating in an infinite baffle, which is chosen as the typical radiation pattern for loudspeakers.Finally, a complete study of the behaviour of different loudspeaker radiation models (such as those usually utilised in the ISO 140-5 measurements) is performed, comparing their radiation maps on the façade for searching their maximum dimensions and the most appropriate radiation configurations.     

Procedure for verification of sound source coverage over façades according to the International Standard ISO 140–5

This paper presents a new verification procedure for sound source coverage according to ISO 140–5 requirements. The ISO 140–5 standard applies to the measurement of façade insulation and requires a sound source able to achieve a sufficiently uniform sound field in free field conditions on the façade under study. The proposed method involves the electroacoustic characterisation of the sound source in laboratory free field conditions (anechoic room) and the subsequent prediction by computer simulation of the sound free field radiated on a rectangular surface equal in size to the façade being measured. The loudspeaker is characterised in an anechoic room under laboratory controlled conditions, carefully measuring directivity, and then a computer model is designed to calculate the acoustic free field coverage for different loudspeaker positions and façade sizes. For each sound source position, the method provides the maximum direct acoustic level differences on a façade specimen and therefore determines whether the loudspeaker verifies the maximum allowed level difference of 5 dB (or 10 dB for façade dimensions greater than 5 m) required by the ISO standard. Additionally, the maximum horizontal dimension of the façade meeting the standard is calculated and provided for each sound source position, both with the 5 dB and 10 dB criteria. In the last section of the paper, the proposed procedure is compared with another method used by the authors in the past to achieve the same purpose: in situ outdoor measurements attempting to recreate free field conditions. From this comparison, it is concluded that the proposed method is able to reproduce the actual measurements with high accuracy, for example, the ground reflection effect, at least at low frequencies, which is difficult to avoid in the outdoor measurement method, and it is fully eliminated with the proposed method to achieve the free field requisite.     

In situ Raman study of mineral phases formed as by‐products in a rotary kiln for clinker production

Portland clinker production consists essentially in the burning of material with defined composition in a rotary kiln at temperatures around 1450 °C. The main fuel used in this process is coal, even though in the last few years the use of alternative fuels has been increasing. Four main minerals are formed, namely, tricalcium and dicalcium silicate, tricalcium aluminate and tetracalcium aluminoferrite. Along with these main phases, variations in burning conditions of fuels or in the local composition of raw materials can lead to the formation of relatively high amounts of secondary by‐products, which can negatively affect the quality of the final material. Characterization of these by‐products allows not only optimization of the process of clinker production but also the design of special refractory materials for the wall of kilns and preheaters. Being found as particles included in (or alternating to) a hard solid clinker matrix, a detailed characterization of these extra phases could be achieved only via microscopic techniques. In this work, micro‐Raman spectroscopy has been successfully tested as a highly selective method for characterization and localization of included minerals that formed as overlapped crusts deposited on the internal wall of a conventional rotary kiln for cement production, without any manipulation of the sample. Understanding the chronological order of deposition of these overlapped layers is extremely important, as it is the only way to go back up to the production process and to individuate the problem. Copyright © 2008 John Wiley & Sons, Ltd.     

FT‐Raman and FTIR spectroscopic characterization of biogenic carbonates from Philippine venus seashell and Porites sp. coral

Some seashells of the Philippine venus species and sea coral of Porites sp. were studied by means of FT‐Raman, Fourier transform infrared spectroscopy (FTIR) and Far‐FTIR spectroscopic methods. The Raman spectra show that both Porites sp. and P. venus are of aragonite‐structured CaCO₃. Detailed spectral analysis, however, reveals some small differences, due to differences in the crystallite size or habit and to different minor element contents. IR spectra show that Porites sp. contains also some small quantities of calcite‐structured carbonates. The ν₂ band (shoulder) of calcite at 875.7 cm⁻¹ is present in the IR spectrum. The separation of the two ν₂ bands (856.4 cm⁻¹ for aragonite and 875.7 cm⁻¹ for calcite) suggests the absence of solid solution of the two polymorphic phases of CaCO₃. Spectroscopic results were confirmed also by X‐ray powder diffraction measurements. Copyright © 2008 John Wiley & Sons, Ltd.     

On‐and off‐site Raman study of rock‐shelter paintings at world‐heritage site of Bhimbetka

Rock‐shelter paintings of Bhimbetka world‐heritage site near Bhopal, India have been investigated using a portable Raman spectrometer. These paintings in the rock shelters belong to periods starting from pre‐historic to the 19th century AD (Gond period). In addition, tiny fragments of pigments (100–200 µm in size) extracted from some of the artworks were also studied in laboratory using a micro‐Raman spectrometer and analyzed using energy‐dispersive X‐ray analysis for elemental composition. Based on the Raman spectra and the elemental analysis mineral‐based pigments such as calcite, gypsum, hematite, whewellite, and goethite could be identified. A comparison of the spectra recorded on‐site using a light‐weight portable spectrometer with those using laboratory equipment is also made and discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

From Portable to SCA Raman devices to characterize harmful compounds contained in used black slag produced in Electric Arc Furnace of steel industry

Black slag from steel production is an industrial waste used as secondary material for some applications (forest tracks, cement, etc.). When it disposed to the open air, little is known about possible side effects that could appear with time. To foresee those side effects, various Raman equipments were used. This analytical strategy has been applied to six different black slag. Four of them were obtained from two steel producers (two original and two with treatment of ‘inerting’), and the other two sampled in civil construction works, which supposedly should be treated. Results showed the original mineral phases of the samples (iron and other metal oxides, silicates, ferrites…) and the new phases (calcite, natron, nitratine, goethite, limonite, ilesite, etc.) resulting from the superficial reaction with the atmospheric acid compounds. This fact indicates a strong reactivity between slag and surrounding environment where they have been deposited. Only with one of the three setups, all the compounds could not be detected: (1) the handheld spectrometer detected the major ones and few of the minor ones, (2) the laboratory Raman microprobe ascertained nearly all of the compounds, but cannot be translated to the field and (3) Structural and Chemical Analyser (SCA), which combines micro‐Raman spectroscopy and Scanning Electron Microscopy/ Energy Dispersive X‐Ray Spectroscopy (SEM‐EDS) on the same spot, recognized the trace compounds, which were the most harmful ones. These results demonstrate the greater applicability of this new strategy in comparison with traditional methods for the chemical characterization of black slag and its alteration products. Copyright © 2013 John Wiley & Sons, Ltd.     

Electron paramagnetic resonance study on metakaolin-admixtured cement paste at different hydrated periods

The present work reports the effect of metakaolin (MK) on the properties of Portland cement through electron paramagnetic resonance study. Cement pastes containing 0%, 10%, 20% and 30% replacements of MK with cement and a water to cement ratio of 0.4 have been prepared. The g factors of Fe(III) and Mn(II) impurities at different hydration ages have been related to changes in the setting time of cement. The increase in g _Fe values and simultaneous decrease in g _Mn values with an increase in the replacement percentage of MK are explained due to pozzolanic reaction.     

Correlations between Raman parameters and elemental composition in lead and lead alkali silicate glasses

This article examines the influence of the composition on the Raman spectra of lead silicate glass. Modern and historic lead alkali glasses and high‐lead glazed ceramics were analysed complementarily by Raman spectrometry and elemental techniques, either electron microprobe, proton induced X‐ray emission (PIXE) or scanning electron microscope with energy dispersive spectrometry (SEM‐EDS). The results showed that lead alkali silicate and high‐lead silicate glasses can be easily distinguished from their Raman spectra profile. In lead alkali silicate glasses, continuous variations were observed in the spectra with the compositional change. In particular, the position of the intense peak around 1070 cm⁻¹ was linearly correlated to the lead content in the glass. A unique decomposition model was developed for the spectra of lead alkali silicate glasses. From the combination of the Raman and elemental analyses, correlations were established between the spectral components and the composition. These correlations permitted to interpret the spectra and access additional compositional information, such as the lead content from area ratio A₉₉₀/A_900–1150, the total alkali + alkaline‐earth content from the area ratio A₁₁₀₀/A_900–1150 or the silica content from the area ratio A₁₁₅₀/A_900–1150. In lead silicate glass containing over 25 mol% PbO, the compositional variation induced no variation in the SiO₄ network region of the Raman spectra [150–1350 cm⁻¹], therefore no correlations and compositional information could be gained from the glass spectra in this range of composition. This new development of Raman spectroscopy for the analyses of glass will be very valuable for museums to not only access compositional information non‐destructively but also to understand the structural changes involved with their alteration. Copyright © 2008 John Wiley & Sons, Ltd.     

Modeling red coral (Corallium rubrum) and African snail (Helixia aspersa) shell pigments: Raman spectroscopy versus DFT studies

Pigments from red coral (Corallium rubrum) and African snail (Helixia aspersa) shell were studied non‐invasively using Raman spectroscopy with 1064‐nm laser beam. The two observed bands because of organic pigments confined in biomineralized CaCO₃ matrix at about 1500 and 1100 cm⁻¹ were assigned to ν(CC) and ν(C―C), respectively. Both signals originate from polyene(s) of largely unknown structure, containing several conjugated CC bonds. The small peak at 1016 cm⁻¹ in the Raman spectrum of coral pigment was assigned to in‐plane ―CH₃ rocking or structural deformation of polyene chain because of spatial confinement in the mineral matrix. The organic pigments in red coral and snail shell were present in inorganic matrix containing aragonite (shell) and calcite (coral). In addition, using Raman spectroscopy, it was observed that aragonite was replaced by calcite as result of healing damaged parts of snail shell. This is an important finding which indicates a great potential of nondestructive Raman spectroscopy instead of X‐ray technique, as a diagnostic tool in environmental studies. To support analysis of the observed Raman spectra detailed calculations using density functional theory (DFT with B3LYP and BLYP density functionals) on structure and vibrations of model all‐trans polyenes were undertaken. DFT calculated CC and C―C stretching frequencies for all‐trans polyenes containing from 2 to 14 CC units were compared with the observed ν(CC) and ν(C―C) band positions of the studied coral and shell. Individual correction factors were used to better match theoretical wavenumbers with observed band positions in red coral and African snail. It was concluded that all‐trans polyene pigments of red coral and dark parts of African snail shell contain 11–12 and 14 CC double bond units, respectively. However, Raman spectroscopy cannot produce any clear information on the presence and nature of the end‐chain substituents in the studied pigments. Copyright © 2016 John Wiley & Sons, Ltd.     

Raman identification of lonsdaleite in Popigai impactites

Micro‐Raman spectroscopy and X‐ray diffraction method (XRD) were used to characterize impact carbonaceous rocks excavated from the Popigai crater (Siberia). The deconvolution of the first‐order Raman spectra of the rocks containing different amounts of carbon phases (diamond, lonsdaleite and graphite) allowed the identification of lonsdaleite spectrum. The most intensive band at 1292–1303 cm⁻¹ was ascribed to A_1g vibration mode of lonsdaleite, whereas the less intense band at 1219–1244 cm⁻¹ was attributed, in agreement with previously reported ab initio calculations, to E_2g vibration mode. The established correlation between the intensities of Raman and XRD peaks permits a rough estimation of lonsdaleite/diamond phase ratio in the impact rocks using micro‐Raman measurements. The second‐order Raman spectra of lonsdaleite–diamond rocks were recorded. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterisation and differentiation of pigments employed on the façade of “Noto’s Valley” monuments (Sicily)

Most of the “Noto’s Valley” monuments façades, located in different towns of Sicily such as Ragusa Ibla, Modica and Noto, present different colours and in many cases the towns themselves are characterized by evident chromatic variations. The knowledge of colour and in particular the characterization of pigments is of utmost importance in the baroque Sicilian buildings, because the peculiarity of the colour is one of the features that makes the “Noto Valley” monuments a World Cultural Heritage site. The present works aim is to characterise and differentiate the pigments used on the façade of monuments and inside the plasters. In particular, we perform a micro-textural and analytical analysis through scanning electron microscopy (SEM) and a mineralogical investigation through the conjunction of optical microscopy and fourier transform infrared spectroscopy (FT-IR). All the experimental results have allowed us to clearly classify the pigments into earths rich in clay minerals and earth containing gypsum. Furthermore, we also show that the earths rich in clay minerals from Ragusa and Modica areas have local provenance.     

Wooden windows: Sound insulation evaluation by means of artificial neural networks

Windows are the weakest part of a façade in terms of acoustic performance: the weighted sound insulation index (R_w), measured according to ISO 140-3, is the fundamental parameter to evaluate the façade acoustic insulation.The paper aims at developing an artificial neural network (ANN) model to estimate the R_w value of wooden windows based on a limited number of windows parameters; this is a new approach because acoustic phenomena are non-linear and affected by a plurality of factors and, therefore, usually investigated through experimentation.Data set is taken from experimental campaigns carried out at the Laboratory of Acoustics, University of Perugia. A multilayer feed-forward approach was chosen and the model was implemented in MATLAB. On the basis of the results obtained by means of a preliminary training and test campaign of several ANN architectures, five main parameters were selected as network inputs: window typology, frame and shutters thickness, number of gaskets, R_w of glazing; R_w value of the window is the network output. Different ANN configurations were trained and a root mean-square error less than 3% was obtained, comparable to measurement uncertainty.This approach allows to develop a model which, with input parameters varying within appropriate ranges, can easily estimate the acoustic performance of wooden windows without experimental campaign on prototypes, saving both money and time. If the training data set is large enough, the presented approach could be very useful for design and optimization of acoustic performance of new products.     

Follow up of the glassy phase formation as silicon oxide was added to Brownmillerite phase of Portland cement clinker

Brownmillerite phase is one of the four main phases of Portland cement clinker. It was prepared as pure C₄AF¹ and C₄AF with different amount of SiO₂, (5, 10, 15, 20, 25, and 40 mol%) by addition. Pure C₄AF was prepared using CaO, Al₂O₃ and Fe₂O₃ according to the ratios 4:1:1. Each sample mixture was fired at 1,400°C for 1 h then ground and introduced again to 1,400°C for 1/2 h then quenched in air. The prepared samples were ground and measured using x-ray diffraction, scanning electron microscope, A.C. conductivity and Mössbauer spectroscopy. The results were correlated and discussed. The main finding is the formation of a glassy phase besides the C₄AF structure, in addition to the formation of the C₂S phase of cement clinker as SiO₂ addition was upgraded. The electrical conductivity results showed that the 20 mol% SiO₂ sample has the lowest (σ) value.     

Study of a tabernacle with a remarkable architectural structure: In situ examination using Raman spectroscopy

In order to characterize ornamental stones and gemstones from the monstrance ‘Tabernáculo de la Colegiata de S. Pedro’ in Lerma, Burgos, a Raman spectroscopy in situ non‐destructive study has been performed on these materials. The Raman spectra obtained correspond to cornalline‐like chalcedony, nephrite jade, quartz veinlets, agates with moganite and jasper, together with goethite showing several degrees of alteration. Various types of marble and lapis lazuli were identified. The lapis lazuli samples show different Raman spectra depending on the blue–white chromatic gradient, due to the variations in the sulfur concentration. Raman spectroscopy allows for the correlation of the presence of radical molecular ions S₂⁻, S₃⁻ and SO₄²⁻, with the colour centres and colouration of lapis lazuli. Two varieties of marble are present, one of brown tones with greyish‐white incrustations and another with alternating white and black veinlets with yellow inclusions. In the former, white masses of microcrystalline calcite appear together with quartz inclusions, around which brown halos of goethite develop as an alteration product. In the latter, they show calcite in the white veinlets and calcite with graphite in the black ones. The mineralogical analysis of ornamentals stones on art objects allows determining their degree of conservation and the extension of the deterioration, in order to establish strategies for the cleaning and restoration. These results are an important factor to date the object and for shedding light about its authorship. Furthermore, it could eventually help to establish connections between the tabernacle‐monstrance and other tabernacles in Castilla y León. Copyright © 2013 John Wiley & Sons, Ltd.