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Cement based materials may contain varying levels of radionuclides, mainly 226Ra (from the 238U series), 232Th and 40K, which are used to determine the Activity Concentration Index ("ACI"). According to the European directive Euratom 2013/59 in these materials, the “ACI” must be < 1 to be suitable for their use in construction. In this paper, data on the activity concentration of natural radionuclides in cementbased materials (i.e. cements, additions, pigments and aggregates) as well as their chemical composition are presented. Radioactivity measurements have been determined by using gamma spectroscopy the chemical compositions have been determined by X-Ray Fluorescence. Data for cements measured shown that white cements present a lower concentration of activity than conventional CEM I. In addition, the CAC (Calcium aluminate cements) present high activity concentration in the 232Th series. Regarding additions, FA (Fly Ash) are those that present the highest concentration of activity in the 238U and 232Th series, while olive biomass ashes are those supplementary cementitious materials that show the highest concentration of activity for 40K. Some pigments used in mortar and concrete technology were also characterized., This study was funded by the Spanish Ministry of the Economy, Industry and Competitiveness under project BIA2016-77252-P. Dr. M.M. Alonso also wishes to thank CSIC for funding the project PIE 2018 60I 054 (Proyecto Intramural de Incorporación).

This study explores the effect of 229Th tracer tail interference on the determination of the sensitivity of 230Th alpha spectrometry of samples with environmental levels of radioactivity. Tracer peak tail interference was calculated with Suma-Alpha, whilst Visual Basic for Applications (VBA in Excel©) software was used to study the variation in sensitivity in terms of the amount of tracer added. Unnecessary increases in the amount of tracer or extended sample measuring times were observed to have adverse effects on method sensitivity (Detection Limit- Ld)., This study was funded by the Spanish Ministry of the Economy, Industry and Competitiveness under project BIA2016-77252-P, ‘Cementos y hormigones preparados con residuos NORM: Comportamiento, Propiedades y Caracterización Radiológica (CHARM)’. Lara García is employed as laboratory technician at CIEMAT's Department of Environmental Radioactivity and Radiological Surveillance (RAYVR) further to research contract CAM-PEJ16/AMB/TL-1459 funded by the Region of Madrid. The authors wish to thank the University of Valladolid and especially Dr Rafael Pardo for their support in the CIEMAT-University of Zacatecas partnership, and the Carolina Foundation for sponsoring Edmundo Escareño's PhD. studies at the University of Valladolid and CIEMAT, Spain.

The durability of Portland cement concrete, regardless of its composition, in presence of low-pH solutions is limited due to the dissolution and decomposition of the mineral phases of the hardened cement. For example, sewage systems are critical to public health however concrete sewer pipes deteriorate very quickly due to acid attack. This problem, in addition to affecting the service life of the pipes, increase the costs of maintenance and can be cause of environmental impacts. The use of alkali-activated or hybrid concretes can be considered a viable option from the basis of their chemical resistance. This study describes the acidic attack behaviour of alkali-activated concretes, based on a low-quality fly ash (FA), using as sources of calcium granulated blast furnace slag (GBFS) and Portland cement (OPC), which were incorporated in a 20% by weight proportion. A mixture of sodium silicate and sodium hydroxide was used as the activating solution. The specimens were exposed to solutions of sulfuric acid (H2SO4) and acetic acid (CH3-COOH) at concentration 1 M for 360 d. As a reference material, conventional concrete was prepared using general-purpose Portland cement. The effect on the compressive strength and mass loss of each mixture was evaluated. The progress of the degradation by acid action was evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The results indicate that alkali-activated concretes show better performance compared with that of OPC concretes with residual strengths at 360 d of exposure between 10 and 20 MPa. In contrast, OPC concrete shows resistance losses of up to 98%. The superior behaviour of alkali-activated concretes is corroborated by the reported lower mass loss (i.e., a maximum of 6%), while that of OPC concrete was up to 19%. In general, gypsum formation is evident in all specimens exposed to H2SO4. In the case of exposure to CH3-COOH, the disappearance of some crystalline products is observed for the alkali-activated concretes. Additionally, it is appreciated the formation of a new crystalline phase, nahcolite. Based in the results, it is possible conclude that this type of alkali-activated binders, (binary and hybrid) based in this type of fly ash, may be used for developing acid-resistant concretes., This study was funded by the Colombian Institute for the Development of Science, Technology, and Innovation COLCIENCIAS (project, “Construction of prototype at the scale of rural housing using innovative materials with low carbon footprint,” Contract 096-2016).

The fast loss of fluidity of sodium silicate-activated slag (SS-AAS) systems have been widely studied in the literature. In this study, the rheology of these cements has been correlated with the evolution of the reaction products formed over time. For this purpose, a combination of experimental characterization techniques, to study the pore solution composition and microstructure of SS-AAS pastes and hermodynamic calculations have been applied. The initial precipitation of ill-defined N-A-S-H and C-N-A-S-H producta leads to a fast increase of the storage modulus after 40 min of reaction. These products are formed from the reaction of the Na+ ions and silicate ions of the activator with the Ca2+ and aluminate species dissolved from the slag. However, when a shear is applied, the structure breaks down and fluidity is recovered, that infers that the attractive forces between the particles are low at the early stages of hydration., The authors thank Prof. Habert (ETHZ) for constructive discussion. Dr. Francesco Caruso (SIK-ISEA) is thanked for helping to develop a protocol for the ICP-OES measurements. Dr. M. Palacios acknowledges Consejería de Educacion ´ e Investigacion ´ (Comunidad de Madrid) for funding the 2016-T1/AMB-1434 project in the frame of “Ayudas de Atraccion ´ de Talento Investigador” and MCIU/AEI/FEDER, UE for funding the RTI2018-099326-A-I00 project. Prof. F. Puertas thanks the Spanish Ministry of Science and Innovation for funding BIA2013-47876- C2-1-P and BIA2016-77252-P projects.

Chemical, physical, mineralogical and radiological characterization of olive biomass fly ash (OBFA) and bottom ash (OBBA) was main objective to determine their potential use as alkaline activators in the preparation of alkali-activated materials or geopolymers. Water solubility tests showed that they released K and Na ions, affording a high pH and alkaline content. Pastes made with 70 wt% vitreous blast furnace slag (SL) and 30 wt% of OBFA or OBBA yielded alkali-activated materials with 28 days mechanical strength of 33 to 18 MPa. In pastes prepared with 30 wt% OBFA, strength values were comparable to those developed by slag pastes activated with a commercial KOH. However, the pastes made with 70 wt% coal fly ash and 30 wt% OBFA or OBBA proved to be inviable because the pH reached was not high enough to activate the precursor. The radiological calculations of OBFA- and OBBA-SL bearing pastes would conform to European legislation on protection against exposure to ionising radiation, for the activity concentration index (ACI) found in the final product was less than 1 in all cases. The pastes leached primarily K. The presence of elements such as 210Po and 210 Pb at the end of the decay chain in the eluates would not limit the use of biomass ash and slag blends. These findings have confirmed the feasibility of using olive oil biomass ashes as an alternative alkaline activator in blast furnace slag systems to produce alkali-activated materials or geopolymers, with properties that make them apt for use as building materials., Funding for the tests conducted in this study was provided by the Spanish Ministry of Economy, Industry and Competitiveness under projects BIA2013-47876-C2-1-P and BIA2016-77252-P.

The aim of the present research is to ascertain the effect of the nature and concentration of the alkaline activator and temperature on the rheological behaviour of alkali-activated fly ash (AAFA) pastes. Furthermore, the reaction process of fly ash has been investigated from rheological measurements. Results have shown that the increase of the activator concentration and the temperature leads to an increase of yield stress and apparent viscosity, mainly at temperatures above 65 °C when dissolution of fly ash and precipitation of hydration products is raised. In general, similar activation energies were determined for alkali-activated fly ash pastes, regardless of the concentration and silica modulus of the activator, concluding that the underlying reaction mechanism is the same independently on the nature of the activating solution., Prof. F. Puertas thanks MINECO (Spanish Ministry) for funding BIA2013-47876-C2-1-P project. Dr. M. Palacios acknowledges Consejería de Educación e Investigación (Comunidad de Madrid) for funding the 2016-T1/AMB-1434 project in the frame of “Ayudas de Atracción de Talento Investigador”.

The purpose of this study is to investigate news activators in the preparation of alkali-activated materials (AAMs) alternative to Portland cements by reusing waste glass. Alkali-activated blast furnace slag (AAS) constitutes an alternative to Portland cement due to high energy and environmental pollution associated with industrial Portland cement. Moreover, alkali activated materials offer a series of higher properties than ordinary Portland cement (OPC), such as better strength and durability behaviour. However, the rheology of these materials has been much less intensely researched. The present study aimed to study the effect of waste glass as activator and as replacement of blast furnace slag on the rheological behaviour of AAS pastes, with a comparison between the rheological parameters and fluidity of these pastes to the same parameters in standard cements (CEM I and CEM III/B). The findings show that AAS paste behaviour of rheology when the activator was a commercial waterglass solution or NaOH/Na2CO3 with waste glass was similar, fit the Herschel-Bulkley model. The formation of primary C-S-H gel in both cases were confirmed. However, the rheological behaviour in standard cements fit the Bingham model. The use of the waste glass may be feasible from a rheological point of view in pastes can be used. © 2015 Sociedad Espanola de Ceramica y Vidrio. Published by Elsevier Espana, S.L.U. This is an open access article under the CC BY-NC-ND license

This paper discusses the results of alkali-activating waste glass in pursuit of a new type of alkali activated materials (AAMs). Waste glass pastes were prepared with different alkaline activators (NaOH, NaOH/ Na2CO3, sodium silicate hydrate and KOH) with different concentrations and cured for 20 h at 85 C and at 99% or 6.5% relative humidity to assess the effect of these variables on paste mechanical strength and microstructure. Compressive strength performance was better at the higher alkaline concentrations and when the pastes were cured at low relative humidity (6.5%), which induced low porosity (MIP) and high specific surface (BET). Irrespective of the type of activator or curing process, the main reaction product was a Si-high, Al-low gel. As a raw material for alkaline cement manufacture, waste glass delivered compact, high-strength cementitious skeletons. This research was funded by the Ministry of Economy and Competitiveness under projects BIA2010-15516 and BIA2013-47876-C2-1-P and the Spanish National Research Council under project PIE201460E06. The authors wish to thank Eduardo Torroja Institute for Construction Science technicians Alfredo Gil, Francisco Morales and Patricia Rivilla for their assistance with the laboratory trials.

The final conclusions and perspectives of the COST network NORM4Building regarding the use and evaluation of the use, of NORM by-products in construction materials.

Within this chapter, four main groups of construction materials that allow the reuse of large quantities of by-products are considered: (1) those based on Portland cements (both as cement itself and as concrete), (2) those based on the alkali activation of different industrial products (mainly ground-granulated blast-furnace slag and fly ash), (3) ceramics and glass-ceramics, and (4) gypsum, in particular phosphogypsum. Particular emphasis is placed upon the types of by-product that could be used in the preparation of these construction materials and on the technical and chemical aspects that govern the reuse. For each by-product a separate section deals on (1) the technical (and chemical) aspects of the use as a construction material and on (2) the resulting radiological properties of the construction material. The considered by-products themselves and their radiological properties are discussed more in detail in Chapter 6., info:eu-repo/semantics/publishedVersion

With increasing environmental pressure to reduce solid waste and to recycle as much as possible, the cement and concrete industries have adopted a number of methods to achieve this goal. Alkaline cements and concretes exhibit highest strength and longest durability when activated with a solution of alkaline silicate hydrates (waterglass). To obtain these alkaline silicates, however, an aqueous solution of the proper proportion of carbonate and silica salts must be heated to a temperature of around 1300 °C. This chapter studies the possibility of synthesizing a new activatorlike waterglass from waste glass reuse through processes of solubility, and explores the feasibility of using this solution as a potential alkaline activator for blast furnace slag (AAS) cement pastes.

Compatibility between three structurally different PCEs and four commercial cements: one non-blended cement and three blended cements, was studied by adsorption, zeta potential, rheological and calorimetric methods. According to the adsorption curve results, the higher the percentage of carboxylates groups in the admixture, the more intensely it is adsorbed on cement pastes. Moreover, admixtures were shown to be adsorbed by the additions as well, being most effectively adsorbed in limestone. From the rheological point of view, the optimum carboxylate group/ester group ratio for the admixtures used in the present study was found to range from 0.7 to 1.2. The fluidizing effect of the admixtures on cement pastes is conditioned by the presence of mineral additions. Despite the low adsorption rates of the admixtures in slag-blended cements, the inclusion of PCEs generated the steepest declines in the rheological parameters. The delay of admixtures on cement hydration intensifies with rising PCE dosage. This admixture-mediated retarding effect was also observed to vary depending on the nature of the addition, and was most intense in slag-blended cement.

The incorporation of mineral additions to Portland cement reduces the amount of clinker required in cement manufacture improving the eco-efficiency of this process. They also impact rheology and it may affect the interaction between superplasticizers and cements. The presented study explores the effect of limestone, fly ash and silica fume on Portland cement and the interaction of these additions with naphthalene (PNS)-, melamine (PMS)-, lignosulfonate (LS)- and polycarboxylate (PCE)-based admixtures. The adsorption isotherms, zeta potentials and rheological behaviour of the blended cements were found and compared to the same parameters in non-blended cement. The results showed that cement–superplasticizers compatibility was altered by the physical (specific surface) and chemical (surface charge) characteristics of the mineral additions studied.

Alkali-activated slag (AAS) binders are obtained by a manufacturing process less energy-intensive than ordinary Portland cement (OPC) and involves lower greenhouse gasses emission. These alkaline cements allow the production of high mechanical strength and durable concretes. In the present work, the adsorption of different superplasticizer admixtures (naphthalene-based, melamine-based and a vinyl copolymer) on the slag particles in AAS pastes using alkaline solutions with different pH values have been studied in detail. The effect of the superplasticizers on the yield stress and plastic viscosity of the AAS and OPC pastes have been also evaluated. The results obtained allowed us to conclude that the adsorption of the superplasticizers on AAS pastes is independent of the pH of the alkaline solutions used and lower than on OPC pastes. However, the effect of the admixtures on the rheological parameters depends directly on the type and dosage of the superplasticizer as well as of the binder used and, in the case of the AAS, on the pH of the alkaline activator solution. In 11.7-pH NaOH-AAS pastes the dosages of the superplasticizers required to attain similar reduction in the yield stress are ten-fold lower than for Portland cement. In this case the superplasticizers studied show a fluidizing effect considerably higher in 11.7-pH NaOH-AAS pastes than in OPC pastes. In 13.6-pH NaOH-AAS pastes, the only admixture observed to affect the rheological parameters is the naphthalene-based admixture due to its higher chemical stability in such extremely alkaline media.

The cement industry has for some time been seeking procedures that would effectively reduce the high energy and environmental costs of cement manufacture. One such procedure is the use of alternative materials as partial replacements for fuel, raw materials or even clinker. The present study explores the reactivity and burnability of cement raw mixes containing fired red or white ceramic wall tile wastes and combinations of the two as alternative raw materials. The results showed that the new raw mixes containing this kind of waste to be technically viable, and to have higher reactivity and burnability than a conventional mix, providing that the particle size of the waste used is lower than 90 μm. The mineralogical composition and distribution in the experimental clinker prepared were comparable to the properties of the clinker manufactured with conventional raw materials. Due to the presence of oxides such as ZnO, ZrO2 and B2O3 in tile glazing, the content of these oxides was higher in clinker made with such waste. The mix of red and white ceramic wall tile waste was found to perform equally or better than each type of waste separately, a promising indication that separation of the two would be unnecessary for the purpose described above., This study was funded by the Spanish Ministry of Education and Science (MEC) under grants for Projects CTM2004-06619-CO2-01 and 02/TECHNO. I. Garcı´a Dı´az and M. Palacios benefited from pre-Ph.D. grants awarded by the MEC and the Region of Madrid (CAM), respectively, and S. Martı´nez-Ramı´rez from a “Ramón y Cajal” contract funded by the MEC and the ERDF.

Publicación en versión impresa: mayo de 2007, The effect of a shrinkage-reducing admixture (SRA) based on polypropylenglycol on the dimensional stability of waterglass-activated slag mortars was studied. The analysis also showed the effect of the admixture on pore structure of the mortars as well as on the mineralogical composition and microstructure of the alkali-activated slag pastes. The SRA reduced the shrinkage by up to 85 and 50% when the alkali-activated slag mortar specimens were cured at relative humidities of 99 and 50%, respectively. The mechanism primarily involved in shrinkage reduction is the decrease in the surface tension of pore water prompted by the admixture. The SRA also modified the pore structure – under both curing conditions – increasing the percentage of pores with diameters ranging from 1.0 to 0.1 μm. Capillary stress is much lower in these pores than in the smaller capillaries prevailing in mortars prepared without admixtures. Microstructurally, the SRA occasioned a slight increase in the proportion of Si units Q2 in the CSH gel and a decrease in the percentage of Al replacing the Si in the gel structure. The admixture did not, however, modify the mineralogical composition of the pastes. Finally, the SRA admixture retarded the alkaline activation of the slag, more intensely at higher admixture dosages. While the admixture did not significantly alter the degree of reaction in pastes cured for 7 days at RH=99%, the value of this parameter dropped by 7% in the presence of the admixture in pastes cured at 50% relative humidity., Funding for project MAT 2001–1490 was provided by the Spanish Ministry of Science and Technology (MCyT). The authors wish to thank A. Gil, J. L. García, I. Sobrados, J. L. Llueca and J. L. Pita for their support in the tests conducted for this study.

[EN]This paper shows how several superplasticizers (polycarboxylates, vinyl copolymers, melamine and naphthalene-based) and shrinkage-reducing (polypropylenglycol derivatives) admixtures affect the mechanical and rheological properties and setting times of alkali-activated slag pastes and mortars. Two activator solutions, waterglass and NaOH, were used, along with two concentrations—4% and 5% of Na2O by mass of slag. All admixtures, with the exception of the naphthalene-based product, lost their fluidifying properties in mortars activated with NaOH as a result of the changes in their chemical structures in high alkaline media. The difference in the behaviour of these admixtures when ordinary Portland cement is used as a binder is also discussed in this paper.

[EN]The objective of this paper was to reproduce the formation of thaumasite due to the reaction of atmospheric SO2 with hydraulic mortars. The research was carried out on mortars made with ordinary Portland cement (OPC), mineralized white Portland cement, hydraulic lime and a mixture of lime and pozzolana. Mortars underwent sulfation by exposing the samples to 300 ppm SO2 at 25 °C and 95% RH for 2 days. Subsequently, half of the sulfated samples were kept for 6 and 12 months in a chamber with 0.3 ppm, SO2 as pollutant (0.50 l min−1 flow gas velocity), 5 °C and 95% RH. The other halves of the sulfated samples were kept partially immersed in water at 5 °C for 4, 9 and 14 months. The process of thaumasite formation in hydraulic mortars due to the interaction of the material with atmospheric SO2 was reproduced in all the hydraulic mortars kept partially immersed in water at low temperature, except in the lime–pozzolana mixture. Gypsum was the first reaction product formed as a result of that interaction. Subsequently, gypsum reacted with calcium carbonate and C–S–H gel resulting in the formation of thaumasite. The formation of thaumasite was easier and quicker in sulfated samples kept at low temperature partially immersed in water. Only in OPC mortars was thaumasite formation observed in samples exposed to 0.3 ppm of SO2 for 12 months.

The development of new binders, alternative to traditional cements and concretes obtained by the alkaline activation of different industrial by-products (blast furnace slags and/or fly ashes), is an ongoing study and research topic of the scientific community. The mechanical and durable behaviour of alkaline cement mortars reinforced with polypropylene fibres has been the object of the present investigation. Three different alkaline matrices were used: (a) granulated blast furnace slag activated with waterglass (Na2SiO3+NaOH) with a concentration of 4% Na2O by mass of slag and cured at room temperature, (b) aluminosilicate fly ash activated with 8M NaOH and cured at 85 °C during the first 24 h and (c) 50% fly ash+50% slag activated with 8M NaOH solution at room temperature. In the mechanical tests (flexural and compressive strengths), two different dosages of fibres were used: 0.5% and 1% by mortar volume. Shrinkage tests according to ASTM C 806-87 standard with (1%) and without fibres were also carried out. The durability tests carried out were freeze/thaw and wet/dry cycles. In these tests, the dosage of fibre was 0.5% by mortar volume. The results obtained show that the nature of the matrix is the most important factor to strength development, more than fibre presence and content amount.

A mechanical, mineralogical and microstructural characterisation of the cement pastes obtained by alkaline activation of fly ash/slag mixtures cured at different temperatures has been carried out. The pastes obtained were characterised by XRD, FTIR, MAS NMR, SEM/EDX, atomic absorption and ion chromatography, also the insoluble residue in HCl was determined. The results obtained have proved the existence of two different reaction products in those activated pastes. The average atomic ratios in the main reaction product were Ca/Sinot, vert, similar0.8, Al/Canot, vert, similar0.6, Si/Alnot, vert, similar2–3. Such analysis corresponds to calcium silicate hydrate rich in Al, which includes Na in its structure. Other reaction product which was detected in the pastes as result of fly ash activation, was an alkaline aluminosilicate hydrate with a three-dimensional structure.

The expansion of alkali-activated granulated blast furnace slag (AAS) cement mortars with reactive aggregate due to alkali–silica reaction (ASR) was investigated. The alkaline activator used was NaOH solution with 4% Na2O (by mass of slag). These results were compared to those of ordinary portland cement (OPC) mortars. The ASTM C1260-94 Standard Test Method based on the NBRI Accelerated Test Method was followed. The nature of the ASR products was also studied by SEM/EDX. The results obtained show that the AAS cement mortars experienced expansion due to the ASR, but expansion occurs at slower rate than with OPC mortars under similar conditions. The cause of the expansion in AAS cement mortars is the formation of sodium and calcium silicate hydrate reaction products with rosette-type morphology. Finally, in order to determine potential expansion due to ASR, the Accelerated Test Method is not suitable for AAS mortars because the reaction rate is initially slow and a longer period of testing is required.

[EN]Physico-chemical properties and mechanical behaviour of ternary cements made by Portland cement, fly ash and limestone are studied. The mixtures at various compositions of clinker, gypsum fly ash and limestone are intimately ground and compared to other compositions without fly ash. Blended fly ash cements are also studied. The results show that fly ash acts as grinding agent by reducing the required time to obtain the same percentage of particles retained on a 80-μm sieve as the standard cement. Fly ash cements lead to an important extension of setting time than limestone cements. The replacement of clinker by limestone gives better mechanical strengths than the mixtures containing fly ash at early days; after 28 days, the cements prepared by incorporation of fly ash gain an important strength. From mechanical point of view, an optima dosage was obtained at 77% clinker, 2% gypsum, 7.5% fly ash and 13% limestone composition.

[EN] The alkali activation of metakaolin is a way of producing high strength cementitious materials. The processing of these materials has been the subject of numerous investigations. The present paper describes the results of a research project initiated to study the stability of these materials when exposed to aggressive solutions. Prisms of mortar made of sand and alkali-activated metakaolin were immersed in deionized water, ASTM sea water, sodium sulfate solution (4.4% wt), and sulfuric acid solution (0.001 M). The prisms were removed from the solutions at 7, 28, 56, 90, 180, and 270 days. Their microstructure was characterized and their physical, mechanical, and microstructural properties were measured. It was observed that the nature of the aggressive solution had little negative effect on the evolution of microstructure and the strength of these materials. It was also found that the 90-day and older samples experienced a slight increase in their flexural strengths with time. This tendency was most pronounced in those samples cured in sodium sulfate solutions. This behavior may be related to the change in microstructure of the cementitious matrix of the mortars cured longer than 90 days. Some of the amorphous material present had crystallized to a zeolite-like material belonging to the faujasite family of zeolites.

[EN]New repair mortars with biocide properties were subjected to acid rain wet/dry cycles in aggressive environment simulation chambers. Those mortars based on lime had a sepiolite addition as a biocide support. The aim of this work was to determine the influence of both the clay and the biocide on mortar behaviour under aggressive solutions. The aggressive solutions used were the following: 1) H2SO4 solution, with pH = 4.5; and 2) “acid rain” solution with pH = 3.5. In the first case (H2SO4 solution), neither the sepiolite nor the biocide had a significant influence on mortar behaviour, while in the second aggressive medium (“acid rain”), sepiolite plus biocide, a decrease in the reaction between the mortar and the “acid rain” were noted.

[EN]The effect of simultaneous addition of varying concentrations of manganese and phosphorus oxides on a C/S ≈ 3 composition has been investigated. Mineralogical changes on synthesized powders were identified by X-ray diffraction, Infra-red spectroscopy and DTA. M3 polymorph's alite formation with Mn and P inclusions less than 0.69 (wt%) Mn2O3 and 0.62 (wt%) P2O5 is shown. The Electron Paramagnetic Resonance investigations of synthesized monoclinic C3S show that Mn ions are in octahedral site as Mn2+ oxidation state. The formed solid solutions could be described with the following cationic vacancies formula: (Ca3−5X Mn4XX)(Si1−2X p2x) O5, with X ≤ 0.005.

[EN]It is well known that the presence of pollution increases the degradation of some building materials. In order to understand the influence of individual pollutants as well as the role of oxidants and water in lime mortar degradation, those materials have been exposed in atmospheric simulation chambers. According to the pollutants used in the chambers (NO, NO2 and SO2), NO2− and NO3− or SO32−and SO42− have been analysed and related with the reaction between the lime mortar and the pollutant. The reactivity order of the different pollutant (NO, NO2 and SO2), in presence and absence of water and/or oxidant has been determined.

The kinetics of hydration of alkali-activated slag (AAS) have been studied for different temperatures. The alkaline activator used was a mix of water-glass and NaOH solution. The degree of reaction was determined by means of the heat of hydration after the induction period. The reaction mechanism determined for AAS pastes was a diffusion mechanism and their activation energy was 57.6 KJ/mol.

[EN]The influence of sand nature on the burnability of white cement raw mixes manufactured using CaF2 and CaSO4 as flux and mineralizer has been studied. A methodology based on a statistical method called Experimental Design is used to establish a model. Raw mixes burnability models have been compared depending on sand nature. An Al2O3 and CaO rich sand enhances raw mix burnability, favouring clinkering. The enhancement is attributed to the different distribution of clayey material in the raw mix.

In this paper a study on the thermal behaviour of C4A3S̄ (in an open system and up to 1500 °C) is presented as well as the kinetics of decomposition of this compound. At temperatures higher than 1300 °C, the thermal decomposition of C4A3S̄ starts. Such a process is linked to a loss of SO2 simultaneously with a production of CA and CaO. After that CA and CaO reacts giving C12A7. If the temperature is lower than 1400 °C or even being higher than 1400 °C (between 1400 and 1500 °C) although only during the first moments, the decomposition process of C4A3S̄ occurs through a solid-gas reaction. This reaction is controlled by a first order kinetic and can be represented by the following equation: F1 (α) = Ln (1 − α) = − kT having a energy of activation Ea = 538 Kj mol. When the temperature surpasses 1400 °C then a melting of at least C12A7 and CA phases takes place. It occurs in such a way that when α > 0,5, the C4A3S̄ decomposition is produced in the presence of a quantity of liquid enough for considerably modifying its kinetic.

A chemical, physical, mineralogical and mechanical characterization has been made of different bedding and repair mortars in mosaics from the Roman town of Italica, Spain. The main cause of deterioration in the superficial mortars is biological attack. In the repair mortars, situated at the deepest levels, all of which are based on Portland cement, the main causes of deterioration are lixiviation, corrosion of metal reinforcements in the concrete, and crystallization of salts in the cement.

Starting from an industrial cement obtained by milling together a new low energy clinker and gypsum, two blended cements containing 20% wt of fly ashes and 10% wt of limestone respectively, have been prepared. The behaviour of these three cements in Na2SO4 dissolution and sea water has been studied. The method used for testing the specimens has been the Koch-Steinneger one. As a consequence of the study it can be said that the three cements keep a good behaviour in all the aggressive media although the strengths are lower (independently of the age of the specimens) in Na2SO4 and sea water than in distilled water. Also, the composition of the hydrated pastes conserved in the aggressive liquids of different periods of time has been studied. The evolution of the content of Ca(OH)2, gypsum and Mg(OH)2 in the pastes as well as the variations observed in the morphology of C-S-H gel along the time and in function of the aggressive medium, seem to keep a good correlation with the strengths evolution. Finally it has been concluded that those cements prepared with the new low energy cement have such a composition that makes them to be resistant to the sulphate attack.

The reactivity of Ca2AlMnO5 towards water was studied, in the absence as well as in the presence of gypsum, based on a comparative study regarding the hydration process undergone by Ca2AlFeO5 in identical conditions. In the absence of gypsum, the hydration reaction of Ca2AlMnO5 (C4AMn) is more strongly exothermal than that produced in Ca2AlFeO5 (C4AF) hydration, generating hydrates of the hexagonal type which contain Mn in their structure. These hydrates exhibit a high degree of stability, and their conversion into cubic hydrates is very slow, as it does not set in but after the seven first days of hydration. The presence of gypsum does not have any retarding effect on C4AMn hydration, which occurs speedily and with remarkable heat release. The hydration product formed is an ettringite-like phase with Mn incorporated in its structure. The formation rate of this ettringite phase is much faster than in C4AF hydration.

Summary A comparative study of the mineralogical composition of damagedartificial building materials (mortars, plasters, etc.) andefflorescences taken from Toledo's cathedral has been carriedout by X-ray diffraction and IR spectroscopy. By means ofthe IR spectroscopy, several salts (Na 2 SO 4 , Na 2 SO 4 .10H 2 O,K 2 SO 4 ,3K 2 SO 4 .Na 2 SO 4 , CaSO 4 2H 2 O' CaSO 4 .K 2 SO 4 .H 2 O, KNO 3 , etc)have been identified. These compounds are present in verysmall amounts and, as a result, their identification by X-raydiffraction is difficult. The interpretation of these data reveals the existence ofseveral simultaneous mechanisms of degradation of the artificialbuildings materials. This is the case with some mortars containingsyngenite which has been produced by reaction of gypsum andK 2 SO 4 . This inolves the previous existence of gypsum as aproduct of degradation of CaCO 3 .

Ca2AlMnO5 compound has been characterized through the following instrumental techniques: X-ray diffraction; IR spectroscopy, electronic spin resonance and differential thermal analysis. The crystalline structure of Ca2AlMnO5 has been shown to be an orthorhombic type. Its cell parameters have been determined as well. In addition, it was verified that all manganese in this phase is present in the Mn3− form. This element occupies both octahedral positions and tetraedral ones in the mentioned orthombic cell. Finally, the differences existing between Ca2AlMnO5 and Ca2AlFeO5 have been determined: the bases by which both phases can be identified by means of the above mentioned instrumental techniques have been established.

Applications of infrared spectroscopy in the field of cement and coImage ncrete are quite significant. The polymorphs of dicalcium silicate can be differentiated by this technique. We have been studying their infrared spectra and we have found that the number of bands have dismished the polymorph βC2S to the αC2S, indicating that there is an increase in the structural symmetry of one polymorph to another.

The effect of manganese substitution into the crystal structure of the tricalcium aluminate Ca3Al2O6 has been studied by X-ray, analytical electron microscopy, IR spectroscopy and electronic spin resonance. The limit of solid solution of manganese in this phase was determined. The formula proposed for this solubility is (Ca2.984Mn0.016)(Al1.979Mn0.021)O6. In presence of CaO and Al2O3 the manganese reacts to give Ca2AlMnO5 phase, reducing appreciably tricalcium aluminate contents.

Limits of substitution of manganese in Ca3SiO5 and Ca2SiO4 have been determined in air and in reducing atmosphere (93% CO2, 7% CO) at 1350°C. The substitution reaches 0.72% and 2.54% Mn in Ca3SiO5 respectively, while in Ca2SiO4 the corresponding limits are 1.53% and 2.34%. In air, Mn substitutes as Mn4+, mainly for Si, while in CO2/CO, more isomorphous replacement of Ca2+ by Mn2+ occurs. The effect of Mn on the silicate-phase polymorphism is described, and IR patterns given for the solid solutions.