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14 pags., 12 figs., 5 tabs., Silanes added during mortar or concrete preparation, may modify the fresh state properties, hydration kinetics and mechanical strength of the final product. The effects of silanes on cement hydration have been widely studied in the literature, however, there is some controversy about its effect at short ages. The present study was undertaken to determine the effect of a TEOS-based alkoxysilane (UCA-T), produced by ultrasound-assisted pre-hydrolysis of an oligomeric precursor, on early age cement paste hydration. The nature of the processes modifying the various stages of cement hydration kinetics in the presence of the alkoxysilane was ascertained by analysing paste composition at several ages (defined on the grounds of calorimetric curve results) using XRD, TG-DTG, FTIR and Raman spectroscopy. The calorimetric curve of pastes containing UCA-T exhibited a new early age, pre-induction period exothermal peak, indicative of UCA-T hydrolysis, C3A and C3S dissolution and ettringite and C–S–H gel precipitation. Portlandite, however, did not precipitate but reacts with the Si(OH)4 sourced from UCA-T hydrolysis to generate further C–S–H gel. The induction period following on that new exothermal peak was considerably longer than the period observed in the reference cement, an effect that intensified at higher UCA-T content., This study was funded by the European Union’s Horizon H2020 Research and Innovation Programme under Grant Agreement No. 760858. Funding was also received from the Regional Government of Madrid, (S2018/NMT-4372 TOP Heritage-CM Programme). The support received from the CSIC’s PTI-PAIS network during the roll-out of both projects is likewise gratefully acknowledged.

Extracellular nucleotides and nucleosides have emerged as important elements regulating tissue homeostasis. Acting through specific receptors, have the ability to control gene expression patterns to direct cellular fate. We observed that SKOV-3 cells express the ectonucleotidases: ectonucleotide pyrophosphatase 1 (ENPP1), ecto-5'-nucleotidase (NT5E), and liver alkaline phosphatase (ALPL). Strikingly, in pulse and chase experiments supplemented with ATP, SKOV-3 cells exhibited low catabolic efficiency in the conversion of ADP into AMP, but they were efficient in converting AMP into adenosine. Since these cells release ATP, we proposed that the conversion of ADP into AMP is a regulatory node associated with the migratory ability and the mesenchymal characteristics shown by SKOV-3 cells under basal conditions. The landscape of gene expression profiles of SKOV-3 cell cultures treated with apyrase or adenosine demonstrated similarities (e.g., decrease FGF16 transcript) and differences (e.g., the negative regulation of Wnt 2, and 10B by adenosine). Thus, in SKOV-3 we analyzed the migratory ability and the expression of epithelium to mesenchymal transition (EMT) markers in response to apyrase. Apyrase-treatment favored the epithelial-like phenotype, as revealed by the re-location of E-cadherin to the cell to cell junctions. Pharmacological approaches strongly suggested that the effect of Apyrase involved the accumulation of extracellular adenosine; this notion was strengthened when the incubation of the SKOV-3 cell with α,β-methylene ADP (CD73 inhibitor) or adenosine deaminase was sufficient to abolish the effect of apyrase on cell migration. Overall, adenosine signaling is a fine tune mechanism in the control of cell phenotype in cancer. J. Cell. Biochem. 118: 4468-4478, 2017. © 2017 Wiley Periodicals, Inc.

The epithelium-mesenchymal transition (EMT) is an important process of cell plasticity, consisting in the loss of epithelial identity and the gain of mesenchymal characteristics through the coordinated activity of a highly regulated informational program. Although it was originally described in the embryonic development, an important body of information supports its role in pathology, mainly in cancerous and fibrotic processes. The purinergic system of inter-cellular communication, mainly based in ATP and adenosine acting throughout their specific receptors, has emerged as a potent regulator of the EMT in several pathological entities. In this context, cellular signaling associated to purines is opening the understanding of a new element in the complex regulatory network of this phenotypical differentiation process. In this review, we have summarized recent information about the role of ATP and adenosine in EMT, as a growing field with high therapeutic potential.

International Conference on Non-Conventional Materials and Technologies: construction for sustainability. Green composites, materials and technologies, Mérida, Yucatán (México), November 26-29, 2017. -- http://www.cicy.mx/sitios/XVII-NOCMAT/index.html#home, It is well known that there are several scientific, technical and environmental advantages of incorporating active additions to the cement, due to its ability to react chemically with the portlandite generated during the hydration reaction of the cement particles, to give more dense and compact matrices. The coal wastes are an alternative source of obtaining future ecological pozzolans, fundamental pillar of the main strategy of the Circular Economy. As a result, an improvement in the blended cement performances was obtained. However, some aspects regarding the durability due to CO2 reaction have not been solved. A wide range of pozzolans (silica fume, fly ash, natural pozzolan, natural metakaolinite) are found in kaolinite-based industrial wastes (paper waste, potable water treatment), which are an excellent alternative for the socio-economic development of a country. The current work presents the scientific-technical advances of coal wastes as supplementary cementing material for the manufacture of low clinker cements and their influence under the action of CO2. The obtained results show that, after thermal activation, the products obtained have a High pozzolanic activity in the range of 550 and 650ºC and the kinetics reaction is similar to other pozzolans of silico-aluminous nature. After exposure to CO2 environment, the behaviour of the pozzolanic material is similar to cement, used as reference, when the percentage of substitution is low; while the 50% blended cements showed a rapid carbonation process.

SUMMARY Adenosine triphosphate (ATP) is released from the cell by multiple mechanisms. The extracellular form of this purine is processed by ectonucleotidases, resulting in a variety of dephosphorylated metabolites that can bind to specific receptors found in the membrane of target cells; such purinergic signaling is important as an autocrine-paracrine intercellular communication system that influences tissue physiology. In this review, we summarize the studies analyzing purinergic activity in the ovary, which can modulate cellular physiology—including sensitivity to gonadotropins—in several ovarian cell types, including the cumulus-cell complex, granulosa cells, theca cells, and the ovarian surface epithelium. These functions support a role for ATP as an important intra-ovarian messenger, and open new lines of research that can improve our understanding of mechanisms regulating ovarian function and the fine-tuning of folliculogenesis. Mol. Reprod. Dev. 82: 839–848, 2015. © 2015 Wiley Periodicals, Inc.

This paper aims to characterize spray-dried DWTP sludge and evaluate its possible use as an addition for the cement industry. It describes the physical, chemical and micro-structural characterization of the sludge as well as the effect of its addition to Portland cements on the hydration, water demand, setting and mechanical strength of standardized mortars. Spray drying DWTP sludge generates a readily handled powdery material whose particle size is similar to those of Portland cement. The atomized sludge contains 12-14% organic matter (mainly fatty acids), while its main mineral constituents are muscovite, quartz, calcite, dolomite and seraphinite (or clinoclor). Its amorphous material content is 35%. The mortars were made with type CEM I Portland cement mixed with 10 to 30% atomized sludge exhibited lower mechanical strength than the control cement and a decline in slump. Setting was also altered in the blended cements with respect to the control.

Extracellular nucleotides are signaling elements present in the tumor microenvironment; however, their role in tumor growth is not completely understood. In the present study, we asked whether nucleotides regulate cell migration in ovarian carcinoma-derived cells. We observed that 100 μM UTP induced migration in SKOV-3 cells (1.57 ± 0.08 fold over basal), and RT-PCR showed expression of transcripts for the P2RY2 and P2RY4 receptors. Knockdown of P2RY2 expression in SKOV-3 cells (P2RY2-KD) abolished the UTP-induced migration. The mechanism activated by UTP to induce migration involves transactivation of the epidermal growth factor receptor (EGFR) since we observed that the EGFR kinase inhibitor AG1478 and the PI3K inhibitor Wortmannin inhibit this response (to 0.76 ± 0.23 and 0.46 ± 0.14 relative to the control, respectively). In agreement with these observations, UTP was able to modify the phosphorylation state of the EGFR; likewise, the induction of ERK1/2 phosphorylation promoted by UTP was abolished by a 30-60 min treatment with AG1478. Our data also suggested that the enhanced cell migration involves the epithelium to mesenchymal transition (EMT) process, since a 12 h stimulation of SKOV-3 cells with 100 μM UTP showed an increase in vimentin and SNAIL protein levels (459.8 ± 132.4% over basal for SNAIL). Interestingly, treatment with apyrase (10 U/mL) reduces the migration of control cells and induces a considerable enrichment of E-cadherin in the cell-cell contacts, favoring an epithelial phenotype and strongly suggesting that the nucleotides released by tumor cells and acting through the P2RY2 receptor are potential regulators of invasiveness.

Adenosine triphosphate (ATP) is released from the cell by multiple mechanisms. The extracellular form of this purine is processed by ectonucleotidases, resulting in a variety of dephosphorylated metabolites that can bind to specific receptors found in the membrane of target cells; such purinergic signaling is important as an autocrine-paracrine intercellular communication system that influences tissue physiology. In this review, we summarize the studies analyzing purinergic activity in the ovary, which can modulate cellular physiology-including sensitivity to gonadotropins-in several ovarian cell types, including the cumulus-cell complex, granulosa cells, theca cells, and the ovarian surface epithelium. These functions support a role for ATP as an important intra-ovarian messenger, and open new lines of research that can improve our understanding of mechanisms regulating ovarian function and the fine-tuning of folliculogenesis.

A chemical, mineralogical and microstructural study was conducted on zeolitic rocks from two different formations in Cuba (Carolinas and Los Congos) to assess their value as pozzolanic components for cement. The samples were characterized using XRD, FTIR, BSE/EDX, optical microscopy 29Si and 27Al MAS NMR and BET-specific surface techniques. The studies showed the Carolinas rock to be hypocrystalline (predominantly glass) and contain subautomorphic and automorphic heulandite and/or clinoptilolite crystals, allotriomorphic calcite crystals–also present around the edges of the vacuoles–, and small, unevenly distributed masses of Fe and Ti oxide. Los Congos sample was found to be a vitreous (holohyaline), perlitic rock whose constituents included albite, small amounts of quartz, tiny veins and unevenly distributed specks of calcite, and Fe and Ti oxide appearing around the edges of cracks, as a cover over the veins and isolated masses, in addition to faujasite. Finally, both rocks were found to have pozzolanic properties. Both rocks exhibited pozzolanic properties, although the reaction rate with portlandite was much higher in the Carolinas than in the Los Congos samples. This result was related not to the particle size distribution of the materials, but to their soluble SiO2 content and mineralogy.

Volcanic pozzolans owe their pozzolanic activity chiefly to the presence of vitreous or zeolitic material rich in SiO2, and Al20y compounds that react with the portlandite produced during cement hydration to generate amorphous gels with cementitious properties. The present study analyzes the modifications taking place in the composition, structure and micro structure of the hydra ted cement paste when 20% of the cement by weight is replaced by two finely ground zeolitic rocks from Cuban deposits. Hydrated cement pastes were prepared with a CEM I35 cement, as well as with mixes of the cement and two Cuban zeolitic rocks (20% by weight). After eight months of hydration, the pastes were characterized -mineralogically, chemically and microstructurally- with XRD, FTIR, 29Si and 27Al MAS NMR, DTA/TG, back scattered electron microscopy and mercury porosimetry techniques. The replacement of 20% by weight of the cement with two finely ground zeolitic rocks significantly modified the composition, structure, quantity and microstructure of the hydrated cement paste reaction product. The C-S-H gel formed in these pastes differed in quantity, which was larger, and composition from the original cement gel. Moreover, the gel formed in addition-free cement had a higher Ca and a lower Al content and shorter silicate chains than the C-S-H product formed in the pastes made with zeolitic rocks. Finally, the pastes with pozzolan additions had fewer and smaller pores., La actividad de las puzolanas de origen volcánico procede fundamentalmente de la presencia de material vitreo o zeolítico rico en SiO2 y Al2Oy que son los que reaccionan con la portlandita producida en la hidratación del cemento generando geles amorfos con propiedades cementantes. El objetivo del presente trabajo es estudiar las modificaciones que produce la sustitución del 20% en peso de cemento por dos rocas zeolíticas cubanas finamente molidas, en la composición, estructura y microestructura de la pasta de cemento hidratada. Se prepararon tres pastas de cemento hidratadas elaboradas con un cemento CEM I 35 y con la mezcla de dicho cemento con dos rocas zeolíticas cubanas (al 20% en peso). A los ocho meses de hidratación las pastas se caracterizaron mineralógica, química y microestructuralmente a través de DRX, FTIR,29Si y 27Al MAS NMR, ATD/TG, microscopía electrónica de electrones retrodispersados y porosimetría de mercurio. La sustitución del 20%> en peso de cemento por las dos rocas zeolíticas finamente molidas, modifica de modo importante la composición, estructura y cantidad de productos de reacción de las pastas de cemento hidratadas así como su microestructura. Así se produce un aumento en la cantidad de gel C-S-H formado, cuya composición es diferente a la del cemento original. El gel C-S-H formado en la pasta de cemento exento de adición es más rico en Ca y más pobre en Al que el gel formado en las pastas con rocas zeolíticas, siendo, ademéis, menor la longitud de sus cadenas de silicatos. Finalmente, la adición de las puzolanas produce pastas menos porosas y un refinamiento del tamaño de los poros.

A study was conducted on the effect of a polycarboxylate (PC) admixture on the mechanical, mineralogical, microstructural and rheological behaviour of Portland cement pastes. It was observed that the presence of PC admixture retards the initial cement hydration reactions, although this effect may be offset by possible increased diffusion in later stages. Additionally, the PC admixtures produce a few alterations in the structure and composition of the formed C–S–H gel. The addition of 1% PC admixture in the pastes generates a higher percentage of silicate bridge (Si Q2 units) mainly at 2 days. The admixture used in this study induced microstructural modifications in the pastes which slightly reduced the porosity; however the admixture did not affect the mechanical strength of the pastes at either 2 or 28 days of hydration. Finally, from the results of the rheological studies it was concluded that a low dosage of PC led to a substantial reduction (over 70%) in the yield stress.

P2X7 is a purinergic receptor-channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non-cancerous and cancer patients were analyzed by immunohistochemistry. Ovarian surface epithelium in healthy tissue expressed P2X7 at a high level that was maintained throughout the cancer. The cell lines SKOV-3 and CAOV-3 were used to investigate P2X7 functions in OCA. In SKOV-3 cells, selective stimulation of P2X7 by 2'(3')-O-(4-benzoylbenzoyl) adenosine-5'-triphosphate (BzATP) induced a dose-dependent increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) but not cell death. Instead, BzATP increased the levels of phosphorylated ERK and AKT (pERK and pAKT), with an EC(50) of 44 ± 2 and 1.27 ± 0.5 μM, respectively; 10 μM BzATP evoked a maximum effect within 15 min that lasted for 120 min. Interestingly, basal levels of pERK and pAKT were decreased in the presence of apyrase in the medium, strongly suggesting an endogenous, ATP-mediated phenomenon. Accordingly: (i) mechanically stimulated cells generated a [Ca(2+)](i) increase that was abolished by apyrase; (ii) apyrase induced a decrease in culture viability, as measured by the MTS assay for mitochondrial activity; and (iii) incubation with 10 μM AZ10606120, a specific P2X7 antagonist and transfection with the dominant negative P2X7 mutant E496A, both reduced cell viability to 70.1 ± 8.9% and to 76.5 ± 5%, respectively, of control cultures. These observations suggested that P2X7 activity was auto-induced through ATP efflux; this increased pERK and pAKT levels that generated a positive feedback on cell viability.

P2X7 is a purinergic receptor-channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non-cancerous and cancer patients were analyzed by immunohistochemistry. Ovarian surface epithelium in healthy tissue expressed P2X7 at a high level that was maintained throughout the cancer. The cell lines SKOV-3 and CAOV-3 were used to investigate P2X7 functions in OCA. In SKOV-3 cells, selective stimulation of P2X7 by 2'(3')-O-(4-benzoylbenzoyl) adenosine-5'-triphosphate (BzATP) induced a dose-dependent increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) but not cell death. Instead, BzATP increased the levels of phosphorylated ERK and AKT (pERK and pAKT), with an EC(50) of 44 ± 2 and 1.27 ± 0.5 μM, respectively; 10 μM BzATP evoked a maximum effect within 15 min that lasted for 120 min. Interestingly, basal levels of pERK and pAKT were decreased in the presence of apyrase in the medium, strongly suggesting an endogenous, ATP-mediated phenomenon. Accordingly: (i) mechanically stimulated cells generated a [Ca(2+)](i) increase that was abolished by apyrase; (ii) apyrase induced a decrease in culture viability, as measured by the MTS assay for mitochondrial activity; and (iii) incubation with 10 μM AZ10606120, a specific P2X7 antagonist and transfection with the dominant negative P2X7 mutant E496A, both reduced cell viability to 70.1 ± 8.9% and to 76.5 ± 5%, respectively, of control cultures. These observations suggested that P2X7 activity was auto-induced through ATP efflux; this increased pERK and pAKT levels that generated a positive feedback on cell viability.

Sulphation of mortars and concretes is a function of diverse environmental factors (SO 2 aerosol, temperature, etc) as well as some material characteristics. One of the phases that could be formed as consequence of the sulphation of the hydraulic binder is thaumasite. In this paper different hydraulic mortars have been exposed to laboratory exposure chambers in order to reproduce thaumasite formation due to atmospheric SO 2 . Under the laboratory exposure conditions, thaumasite was formed in hydraulic lime mortars, and mortars elaborated with ordinary Portland cement as well as mineralized white portland cement. However, thaumasite was not formed in mortars made of lime and pozzolan. The first product formed as a result of the SO 2 -mortar interaction was gypsum. Gypsum reacted with calcite and C-S-H gel, present in the samples, giving place to thaumasite. Low temperature promotes thaumasite formation.

The chemical reactions that occur during the hydration of Portland cement can be modified in the additional presence of certain compounds, such as SO 2 , which may be present in areas of high pollutant gas concentration. This paper considers mortars that have been cured for 1 and 7 days and exposed to SO 2 gas under dry and wet conditions. The role of ozone as gaseous catalyst in the reactions is studied. Fourier transform infrared spectrum analysis of the surface of the samples revealed carbonation had occurred; however, X-ray diffraction of the bulk material from the samples revealed Ca(OH) 2 only when the samples were exposed to dry conditions. In wet conditions, in the presence of water, the dissolution of CO 2 gas is enhanced, the carbonation of the Ca(OH) 2 is promoted at higher levels, and thus no Ca(OH) 2 is detected. Under wet conditions, the degree of salt formation was greater than in dry conditions. In the presence of water, and due to Ca(OH) 2 carbonation, the pH of the pore solution is lower than 12; thus SO 3 2− formation is favored. For the mortars exposed to dry conditions, kinetic salts such as K 2 SO 4 are formed. However, in the additional presence of water, thermodynamically stable products as K 2 Ca(SO 4 ) 2 · 2H 2 O and CaSO 4 · 2H 2 O are detected. The results of scanning electron microscopy indicated that the morphological composition of C-S-H gel resembles needle-like structures radiating from a grain. This morphology has been described by Taylor as type I.

The reaction of portland cement mortars with SO2 gaseous pollutant and artificial 'acid rain' solution has been examined using laboratory exposure chambers, with realistic presentation rates of pollutants. The mortar were previously carbonated to produce superficial carbonation. Two mortars with different w/c ratio and hence specific surface were prepared and exposed into the chambers. For dry deposition of SO2 pollutant gas, the important roles of water and water plus oxidant in increasing chemical reaction are readily revealed. Further, accessible porosity also increases reaction through increased times of reaction of pollutant with the mortars. Interestingly, in the absence of deliberate surface wetting, the presence of oxidant, ozone, leads to a reduction in the already limited extent of reaction. Wet deposition studies using artificial 'acid rain' solution result in gypsum formation, which is more extensive for mortars of increased w/c ratios., Se han realizado ensayos de laboratorio de simulación de los procesos ambientales de "deposición" seca y húmeda sobre morteros de cemento portland, estudiándose las reacciones que se producen con el contaminante SO2 ("deposición" seca) y la disolución de 'lluvia acida' ("deposición" húmeda). Los morteros de cemento se carbonataron para favorecer la carbonatación superficial de los mismos. Se prepararon morteros con dos relaciones a/c con el fin de estudiar la influencia que la variable superficie específica tenía en el proceso de deterioro de dichos materiales. En los estudios de deposición seca con SO2 como gas agresivo se ha visto la importancia que el agua y el agua junto a un oxidante tienen en la reacción del contaminante con los componentes del mortero. La superficie específica Juega un papel importante, ya que al aumentar, aumenta la reacción con el contaminante. La reacción en presencia de oxidante, (SO2+O3) es inferior en medio con aporte sólo de S2. Los estudios de deposición húmeda usando una disolución de 'lluvia acida ', producen la formación de yeso, fundamentalmente para los morteros de mayor relación a/c .

Póster presentado en el International Congress Science and Technology for the Conservation of Cultural Heritage (TechnoHeritage), celebrado en Santiago de compostela del 2 al 5 de octubre de 2012., The effectiveness of two permanent anti-graffiti treatments, a commercial fluoroalkyl siloxane and an organically modified silicate (Ormosil), in two artificial building materials, brick and lime mortar, was analyzed. The research was based on the assessment of the physical properties, cleaning efficiency and durability of the coated construction materials. The results showed that both treatments induced minimal chromatic variations in the materials surface. Ormosil was a better water repellent for its greater capacity to fill the pore systems that enhanced materials resistance to freeze-thaw cycles while lowering their water vapour permeability. Graffiti (alkyd spray paint) cleaning was satisfactory for the brick, after 4 cycles, particularly with the commercial anti-graffiti. On the other hand, lime mortar resisted only one cleaning episode, which removed not only the paint, but part of the material surface., Funding from the Spanish Ministry of Education and Science (Project CONSOLIDER CSD2007-00058) and the Regional Government of Madrid (Geomaterials Programme) is gratefully acknowledged.

Comunicación presentada en el International Congress Science and Technology for the Conservation of Cultural Heritage (TechnoHeritage), celebrado en Santiago de compostela del 2 al 5 de octubre de 2012., Sulfate attack by ground waters, soils, etc. is one of the threats to the built heritage in concrete. This study validated through thermodynamic modeling with GEMS geochemical code a new sulfate-resistant formulation based on the addition of BaCO3 and BaO to ordinary Portland cement (OPC), which could be used to replace weathered concrete. The thermodynamic calculations pointed out that Ba ions were able to form an insoluble salt, barite (BaSO4) with the dissolved sulfate which inhibited the formation of ettringite, the latter oc- curred when the concentrations of BaCO3 and BaO were ≥ 6 and ≥ 4 wt.%, respectively. The results of a simulated sulfate a ttack revealed that ettringite precipitated upon ingression of ≥46 ml of a Na2SO4 solution (44 wt.%) in OPC blends with 20 wt.% of BaCO3; whereas with 20 wt.% of BaO, the sulfate that precipitated besides ba rite was monosulfoaluminate when sulfate solution was ≥40 ml (tested up to 52 ml)., Funding from the Spanish Ministry of Education and Science (Project CONSOLIDER CSD2007-00058) and the Regional Government of Madrid (Geomaterials Programme) is gratefully acknowledged.

We performed an observational study that compared baseline and subsequent blood pressure (BP) measurements and its association with haematoma enlargement (HE) in patients with intracerebral haemorrhage (ICH).We prospectively studied consecutive patients with supratentorial spontaneous ICH within the first 6 h after the onset of symptoms. HE was defined as an increaseor=33% in the volume of haematoma on the CT obtained 24-48 h after the onset of symptoms as compared with the CT at admission. We recorded systolic BP (SBP), diastolic BP (DBP) and mean BP (MBP) at admission and at 6, 12, 18 and 24 h after onset; the maximum SBP, DBP and MBP during the study period; the maximum SBP and DBP within intervals; the mean of all BP readings; administration of antihypertensive agents.We studied 60 patients whose mean age was 72.1 +/- 11.3 years. HE was observed in 27 (45%) patients. No statistically significant differences were observed in any of the analyses that compared BP parameters between the HE and non-HE groups (two-way anova).In an exploratory analysis, we did not find an association between BP and HE within the first 24 h after an acute ICH.

Publicación en versión impresa: mayo de 2007, The composition, structure and properties of the reaction product resulting from the alkali activation of metakaolin (MK) are directly impacted by the specific surface and composition of the initial kaolin and the type, concentration and relative amount of alkali activator used. This study aimed to analyze the effect of these parameters on the flexural strength, degree of reaction, porosity and chemical and mineralogical composition of alkali-activated metakaolin pastes. Two types of metakaolin with different specific surfaces were activated under hydrothermal conditions (85 °C, 2 h) using solutions consisting of waterglass and Na(OH) as activators (Na concentrations = 6, 8, 10, 12, 15, 18, 20 M) and two metakaolin/solution ratios. Regression analysis was used to quantify the effect of the parameters tested (activator concentration and MK/solution ratio) on flexural strength. Mathematical models were likewise built to relate the degree of reaction and amount of sodium fixed in the polymer structure to the synthesis parameters. According to 29Si and 27Al MAS NMR, XRD, FTIR, DTA/TG data and chemical analysis, the material obtained by activating two MKs with waterglass plus NaOH was an amorphous hydrated sodium aluminosilicate in which a Q4 Si (3Al) type three-dimensional structure predominated, i.e., a structure where three Al atoms are connected to SiO4 tetrahedra. The alkaline ions in the structure maintain the electrical balance. The general formula obtained for this inorganic polymer was Na2O·3SiO2·Al2O3·3H2O., The authors are grateful Dr. Jesu´ s Sanz and Dr. Mª Isabel Sobrados for their help in the interpretation of NMR. They also thank to CICYT for the funding received from project MAT2003-08343. Dr Sagrario Martı´nez-Ramı´rez participated in this research under a Ramon y Cajal contract awarded by the Ministry of Science and Technology and cofunded by the European Social Fund.

[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 behaviour of lime mortars containing sepiolite or sepiolite plus pentaclorophenol in atmospheric simulation chambers has been studied. The pollutant gases used in this study have been NO, NO2, and SO2. The studies has been done in wet and dry conditions as well as with and without ozone. In the case of NO and NO2, the aggressive agent would be HNO3, which reacts with lime mortar binder CaCO3, producing Ca(NO3)2 formation. On this process, the influence of the presence of an oxidant as well as water has been studied. The catalyst effect of the oxidation is known to be accelerated by water presence, so mortars exposed to NO + O3 + H2O and NO2 + O3 + H2O environments undergo a greater salts formation than those exposed to the rest of the aggressive media. The three mortars’ behaviours are similar and independent of their composition, producing small amount of salts in every case. When SO2 is the gas used, the aggressive agent of mortar will be H2SO4 that reacts with mortar binder, CaCO3 to produce calcium sulphate in the form of gypsum. Oxidant and/or water influence has been studied, and the (SO2 + O3 + H2O) chamber was found to be the one with greater aggressivity to mortars. However, in these conditions, sepiolite presence within the mortars delayed gypsum formation.