A.E. Paolini

Sapienza University of Rome, Roma, Latium, Italy

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Publications (35)61 Total impact

  • Teresa Mangialardi · Mario Berra · Antonio Evangelista Paolini

    No preview · Article · Jul 2015 · Waste and Resource Management
  • Mario Berra · Teresa Mangialardi · Antonio Evangelista Paolini
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    ABSTRACT: The reuse of woody biomass fly ash (WBFA) as a mineral admixture or as a filler/partial sand replacement material in cementitious mixes was investigated. Three different WBFAs were used, two coming from virgin wood and one from treated wood combustion. The physical and chemical characteristics of these ashes and the technological properties (workability, setting, compressive strength) of cementitious mixes incorporating WBFA were evaluated. It was found that, in spite of the satisfactory technological properties exhibited by most related blended cements, the studied WBFAs did not meet the UNI EN 450-1 requirements for reuse as mineral admixtures, even if they were subjected to a preliminary water-washing treatment. The reuse of raw wood fly ash as a filler/partial sand replacement material was found to be satisfactory and possible for low-quality concrete.
    No preview · Article · Feb 2015 · Construction and Building Materials
  • Umberto Costa · Teresa Mangialardi · Antonio Evangelista Paolini
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    ABSTRACT: The effectiveness of blended cements (three pozzolanic cements - two with natural pozzolana and one with coal fly ash - and one blast-furnace cement) in counteracting alkali-silica reaction (ASR) was assessed by using both the ASTM C1567 accelerated mortar bar expansion test and the accelerated concrete prism expansion test at 38°C and 100% RH. A low-alkali Portland cement was also tested as ASR inhibitor. The results of the mortar and concrete expansion tests were analyzed through a kinetic-based model (KAMJ model) to evaluate the expansion rate constant, k, and the Avrami exponent M. These two kinetic parameters were taken as efficacy parameters for each type of inhibitor. The results of the concrete prism expansion tests were also analyzed through an innovative methodological approach and a third efficacy parameter, such as the potential minimum alkali contribution by the inhibitor to concrete (Lim), was evaluated. It was found that the values of ln(k)mb =-6.0 for mortar bars and ln(k)cp = -7.7 for concrete prisms were appropriate efficacy criteria for discriminating between deleteriously expansive and non-deleteriously expansive mortar or concrete mixes, respectively. In the case of concrete mixes, a good relationship between the efficacy parameter Lim and the kinetic parameter Mcp was found, thus demonstrating the suitability of Mcp as a criterion for ranking not expansive concrete mixes. With respect to the kinetic parameters ln(k)cp and Mcp, the efficacy parameter Lim appears to be of greater technological interest, the last being strictly related to the composition of the concrete mix.
    No preview · Article · Aug 2014 · Journal of Advanced Concrete Technology
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    Full-text · Dataset · Jul 2014
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    Full-text · Dataset · Jul 2014
  • Mario Berra · Umberto Costa · Teresa Mangialardi · Antonio E. Paolini
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    ABSTRACT: A new methodological approach, based on two innovative parameters such as the threshold alkali level (TAL) of aggregates and the tolerable driving force (Δtol) provided by an inhibitor of the deleterious alkali-silica reaction (ASR), was used for the assessment of the ASR expansivity of concrete mixes made with different alkali-reactive aggregates and different cements (one limestone-Portland (or Portland) cement, three pozzolanic cements and one blast furnace cement). Concrete prism expansion tests were performed under two different test conditions: 38 °C and 100 % RH or 60 °C and 100 % RH. The alkali-reactivity of the aggregates was also evaluated by using the petrographic examination and the ultra-accelerated mortar bar expansion test in 1 M NaOH solution at 80 °C. The test results were interpreted according to the innovative methodological approach, as well as according to a traditional approach based on pass-fail criteria. It was found that the two parameters, TAL and Δtol, are appropriate for both assessing the alkali-reactivity of aggregates (TAL) and comparing the efficacy of blended cements as ASR inhibitors (Δtol). These two parameters may be rapidly evaluated (150 days of testing) by using the accelerated concrete prism expansion test at 60 °C and 100 % RH.
    No preview · Article · Jan 2014 · Materials and Structures
  • Antonio Evangelista Paolini · Mario Berra · Marco Sebastiani · Fabio Carassiti · Teresa Mangialardi
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    ABSTRACT: The influence of nanosilica (nanoscale-size particles of amorphous silica) on the leaching behaviour of Portland cement pastes made with a relatively low water/binder ratio (w/b 0.36) and different nanosilica contents (0-3.8 wt% of binder) was investigated through the use of an ultra-accelerated leaching test (using concentrated ammonium nitrate solution as a leachant) coupled with scanning electron microscopy-energy dispersive spectroscopy and differential scanning calorimetry-thermogravimetric analyses. The effect of leaching on the physical and mechanical properties of such pastes was assessed and their chemical resistance to leaching was evaluated through a parametric model. It was found that the addition of nanosilica improves the chemical resistance of cement pastes by producing a significant leaching deceleration (up to 69%). As a result, the decay of compressive strength of leached specimens (about 60% reduction) is significantly retarded. Higher residual compressive strengths were also obtained for totally leached specimens containing nanosilica, as a result of the ability of this admixture to consume portlandite during cement hydration and then reduce the porosity associated with portlandite dissolution during leaching.
    No preview · Article · Dec 2013 · Advances in Cement Research
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    ABSTRACT: The effect of nano-size particles of amorphous silica (nanosilica) on the rheological behaviour and mechanical strength development of cementitious mixes is addressed. Mini-slump and rheometric tests were carried out on cement pastes made with three dose levels of nanosilica at different water/binder ratios. Cement paste workability resulted to be significantly lower than expected for the adopted water/binder ratios, as a consequence of instantaneous interactions between nanosilica sol and the liquid phase of cement pastes, which evidenced the formation of gels characterised by a significant water retention capacity. The resulting reduction of the mix workability was avoided by suitable addition procedures of superplasticizers. No appreciable improvement in the compressive strength development of cementitious mixes by nanosilica addition was observed, in contrast with some results from literature. This confirms conflicting experience on the problem, but some parameters affecting the strength development were identified and discussed.
    No preview · Article · Oct 2012 · Construction and Building Materials
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    ABSTRACT: A methodological approach, based on some innovative reactivity parameters such as the threshold alkali level (TAL) of aggregates and the tolerable driving force (Δtol) of the deleterious expansive process associated with alkali–silica reaction (ASR), is proposed in order to assess the alkali-reactivity of aggregates and compare the effectiveness of different types of ASR inhibitors (low-alkali Portland cements, lithium compounds, and blended cements manufactured with active mineral additions). The effectiveness of the ASR inhibitors, expressed in terms of Δtol, is related to the naturally available alkali content of concrete and the TAL of the aggregate used in the concrete mix. The potential minimum contribution of alkalis (L im) by a given ASR inhibitor to the concrete mix is proposed as a specific efficacy parameter. The relationships between the effective dose levels of mineral additions or lithium compounds and the efficacy parameters Δtol and L im have also been identified. The test procedures for the experimental determination of such parameters are described and some methodology applications to published ASR expansion data are reported.
    No preview · Article · Jun 2012 · Materials and Structures
  • Marcello Dell'Orso · Teresa Mangialardi · Antonio Evangelista Paolini · Luigi Piga
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    ABSTRACT: A new leaching test on comminuted (0.125-2.0mm gradation) cementitious matrices, designated as Modified-Pore Water (M-PW) test, was developed to evaluate the effect of varying leachate pH (4-12.8) and/or liquid-to-solid, L/S, ratio (0.6-50 dm(3)/kg) on the availability factor, F(AV), of heavy metals. The M-PW test was applied to leaching of lead and zinc ions from ground Portland cement mortar incorporating Municipal Solid Waste Incinerator (MSWI) fly ash. Correlation of M-PW test results (F(AV)-L/S data) allowed the determination of the pore-liquid availability factor, F(AVP), at different leachate pHs. These F(AVP) values were utilized, in conjunction with a kinetic pseudo-diffusional model, to evaluate the leaching behavior of monolithic mortar specimens subjected to dynamic leaching tests (constant leachant pH 4 or 6).A good agreement was found between the effective diffusion coefficients, D(e), of lead and zinc ions calculated by such a methodological approach and those obtained from recognized microstructural models. In contrast, no satisfactory agreement was found when these D(e) values were compared with the ones calculated from the results of other availability tests on granular solid samples (NEN 7341 and AAT tests).
    No preview · Article · Apr 2012 · Journal of hazardous materials
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    ABSTRACT: The feasibility of using woody biomass fly ash (WBFA) as a mineral admixture in cement-based materials was investigated. This fly ash was characterized for chemical composition and used to prepare a cement blend with 70wt% Portland cement and 30wt% WBFA. Cubic specimens were cast from a blended cement paste (water-to-binder ratio 0.50) and, after 28 days of curing at 20°C and 100% relative humidity, these specimens were tested for heavy metal leachability through the use of a sequential leaching protocol, at a constant pH of leachant (deionized water; pH6.0). It was found that, except for the chloride content, the WBFA is able to meet the European chemical requirements established for reuse of coal fly ash in cement-based materials. Although the WBFA is characterized by a significant content of heavy metals of particular environmental concern (Cd, Cr, Cu, Ni, Pb, Zn), the results of the monolith leaching test have shown a good immobilization capacity of such metals by the cementitious matrix and, consequently, a good environmental quality of the blended cement investigated.
    Full-text · Chapter · Jul 2011
  • M. Berra · G. Faggiani · T. Mangialardi · A. E. Paolini
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    ABSTRACT: The primary objective of this study was to ascertain whether the Threshold Alkali Level (TAL) of the concrete aggregates may be taken as a suitable reactivity parameter for the selection of aggregates susceptible of alkali-silica reaction (ASR), even when ASR expansion in concrete develops under restrained conditions. Concrete mixes made with different alkali contents and two natural siliceous aggregates with very different TALs were tested for their expansivity at 38°C and 100% RH under unrestrained and restrained conditions. Four compressive stress levels over the range from 0.17 to 3.50N/mm2 were applied by using a new appositely designed experimental equipment. The lowest stress (0.17N/mm2) was selected in order to estimate the expansive pressure developed by the ASR gel under “free” expansion conditions. It was found that, even under restrained conditions, the threshold alkali level proves to be a suitable reactivity parameter for designing concrete mixes that are not susceptible of deleterious ASR expansion. An empirical relationship between expansive pressure, concrete alkali content and aggregate TAL was developed in view of its possible use for ASR diagnosis and/or safety evaluation of concrete structures.
    No preview · Article · Sep 2010 · Cement and Concrete Research
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    Berra M. · De Casa G. · Ergul S. · Mangialardi T. · Paolini A.E.
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    ABSTRACT: Fly ashes from co-fired woody biomass (virgin wood chips) and peat combustion were considered for their use as cement replacement in cementitious mixes. The objective of this work was to investigate the effects of two additions (15 and 30 wt.% of binder) on the flow and rheological properties, setting, and compressive strength of such mixes. The effectiveness of a water-washing pre-treatment of fly ashes was also ascertained. The preliminary results obtained showed that the studied fuel ash may be used as a mineral addition in cementitious mixes. It produces a remarkable increase in the water demand but does not adversely affect cement setting and strength development in the case of superplasticized cement mixes. The washing pre-treatment of raw fly ash is able to reduce or eliminate its adverse effect on the flow and rheological property, but it does not significantly modify the mechanical strength development
    Full-text · Conference Paper · Sep 2009
  • Maria Anna Cinquepalmi · Teresa Mangialardi · Liliana Panei · Antonio Evangelista Paolini · Luigi Piga
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    ABSTRACT: The reuse of cement-solidified Municipal Solid Waste Incinerator (MSWI) fly ash (solidified/stabilised (S/S) product) as an artificial aggregate in Portland cement mortars was investigated. The S/S product consisted of a mixture of 48 wt.% washed MSWI fly ash, 20 wt.% Portland cement and 32 wt.% water, aged for 365 days at 20 degrees C and 100% RH. Cement mortars (water/cement weight ratio=0.62) were made with Portland cement, S/S product and natural sand at three replacement levels of sand with S/S product (0%, 10% and 50% by mass). After 28 days of curing at 20 degrees C and 100% RH, the mortar specimens were characterised for their physico-mechanical (porosity, compressive strength) and leaching behaviour. No retardation in strength development, relatively high compressive strengths (up to 36 N/mm2) and low leaching rates of heavy metals (Cr, Cu, Pb and Zn) were always recorded. The leaching data from sequential leach tests on monolithic specimens were successfully elaborated with a pseudo-diffusional model including a chemical retardation factor related to the partial dissolution of contaminant.
    No preview · Article · Apr 2008 · Journal of Hazardous Materials

  • No preview · Conference Paper · Sep 2007
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    G De Casa · T Mangialardi · A.E. Paolini · L Piga
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    ABSTRACT: A step-wise treatment of Municipal Solid Waste (MSW) incinerator fly ash including washing, milling and sintering was investigated in order to manufacture ceramic materials with improved physical, mechanical and environmental properties and, possibly, to reduce the power input of the sintering process. An interpretation of the test results based on the microstructure of sintered products and sintering kinetic modeling was also attempted to identify the densification mechanisms. It was found that milling of washed fly ash represents a basic step for manufacturing high-density ceramic materials with very high compressive strengths (up to 500 N/mm2). A significant reduction in the power input of the sintering process (reduction of firing temperature from 1210 degrees C for washed fly ash to 1140 degrees C for milled-washed fly ash) is also achieved. A dense, well-sintered microstructure is formed through an intermediate-stage, liquid-phase sintering mechanism controlled by liquid-phase diffusion and grain shape accommodation. Such a microstructure is able to strongly immobilise heavy metals, thus giving good environmental properties to sintered product.
    Full-text · Article · Feb 2007 · Waste Management
  • M. Berra · T. Mangialardi · A. E. Paolini
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    ABSTRACT: In this study, the suitability of the threshold alkali level, TAL, the kinetic parameter, In k, and the microstructural disorder coefficient, Cd, of the aggregates, taken as alkali-silica reactivity criteria, was assessed using different typologies of Italian natural ASR-susceptible aggregates of known field performance. The TAL, In k, and Cd were determined using a modified version of the RILEM AAR-3 concrete prism expansion test, the ASTM C1260 mortar-bar expansion test, and the infrared spectroscopy test, respectively. It was found that the three reactivity criteria are all appropriate for discriminating between reactive and innocuous aggregates. However, the TAL proves to be a more suitable criterion for interpreting the field performance data of the aggregates investigated. There exists a linear relationship between TAL and In k, or between TAL and Cd, which provides a rapid means of estimating the threshold alkali levels of ASR-susceptible aggregates from the results of the ultra-accelerated mortar-bar test and/or the infrared spectroscopy test. A TAL-based classification of the degree of reactivity of the aggregates, as well as some modifications of the reactivity domains established by the infrared spectroscopy method are also proposed.
    No preview · Article · Jan 2005 · Materials and Structures
  • M. Berra · T. Mangialardi · AE Paolini
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    ABSTRACT: The suitability of an ultra-accelerated concrete prism expansion test (testing concrete mixes in alkaline solutions at 150°C) for the assessment of alkali-silica reactivity (ASR) was investigated using concrete mixes made with different alkali levels and different typologies of Italian natural aggregates of known field performance. The results of previous concrete prism expansion tests at 38°C and 100% RH were used for comparative purposes. It was found that the ultra-accelerated test is appropriate for discriminating between innocuous and potentially alkali-reactive concrete mixes and may also be used as a rapid method for evaluating the threshold alkali levels of ASR-susceptible aggregates. The results of the ultra-accelerated test may be interpreted on the basis of apercent expansion criterion (0-12% at 21 days) or through the use of a reactivity parameter, In k, the latter being determined from the correlation of the test results with a kinetic-based method. A value of -3.4 for ln k appears to be a suitable reactivity criterion for interpreting the results of the ultra-accelerated concrete prism test.
    No preview · Article · Jan 2005 · Magazine of Concrete Research
  • M. Berra · T. Mangialardi · A. E. Paolini
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    ABSTRACT: Cette étude a eu pour but de vérifier la fibilité de la méthode de qualification française AFNOR P18-542 [3] et de son équivalent canadien CSA A23.2-27A [4], lorsque ces dernières sont utilisées pour évaluer la réactivité potentielle alcalis-silice (A-S) de certains sables siliceux naturels d'origine italienne, dont le comportement en service à long terme était déjà bien connu. On a également mis au point une nouvelle méthodologie de qualification qui repose sur l'utilisation de l'examen pétrographique (ASTM C295) [9], de l'essai d'expansion sur mortier MICROBAR (AFNOR P18-588) [13] et d'une méthode de détermination du niveau de seuil des alcalis, NSA [8]. S'il a été démontré que la méthode de qualification canadienne n'est pas la plus indiquée pour évaluer la réactivité potentielle A-S des sables examinés, l'évaluation diagnostique fournie par la méthodologie française semble quant à elle pleinement satisfaisante. Toutefois, ces deux méthodes semblent inadéquates lorsqu'il s'agit de prévoir, en termes rigoureux, le comportement expansif d'un granulat donné, en réponse à une variation de la composition et/ou des conditions d'exposition ambiante du béton. Par contre, la méthodologie de qualification proposée, qui repose essentiellement sur le niveau de seuil des alcalis, NSA, servant de paramètre de réactivité pour les granulats siliceux, semble présenter de meilleures garanties, tout du moins en ce qui concerne les sables examinés. In this study, the reliability of both the French (AFNOR P18-542) [3] and the Canadian (CSA A23.2-27A) [4] test methodologies for the qualification of aggregates susceptible of alkali-silica (A-S) reaction in concrete was verified on some Italian natural siliceous sands of known long-term field performance. A new test methodology, based on the utilization of the petrographic examination (ASTM C295) [9], the mortar-microbar expansion test (AFNOR P18-588) [13] and a method of determination of the threshold alkali level, TAL, [8] was also developed. It was found that the Canadian test methodology does not appear to be appropriate for evaluating the potential alkalireactivity of the tested sands. Conversely, a correct diagnosis for the A-S reactivity of these sands is obtained through the use of the French test methodology. However, both test methodologies do not appear suitable for strictly predicting the expansive behaviour of a given aggregate when subjected to variations of composition and/or environmental exposure conditions of concrete. The proposed test methodology, which is essentially based on the use of the threshold alkali level, TAL, as a reactivity parameter, appears to be more appropriate for such a prediction, at least for the sands investigated.
    No preview · Article · Jun 2003 · Materials and Structures
  • M. Berra · T. Mangialardi · AE Paolini
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    ABSTRACT: The effectiveness of Li2CO3 and LiNO3 in preventing expansive alkali-silica reactivity in concrete mixes made with two natural siliceous aggregates and different alkali contents was investigated using both the expansion test at 38degreesC and 100% RH and the ultra-accelerated expansion test in alkaline solutions at 150degreesC. LiNO3 proves to be always effective while Li2CO3 is effective only when the difference between the concrete alkali content (L-ac) and the threshold alkali level of the aggregate (TAL) does not exceed 1.7 kg Na(2)Oeq/m(3) and the concrete mixes are stored at 38degreesC and 100% RH. The ultra-accelerated test methods proves to be appropriate for determining the effective dosages of LiNO3 in concrete mixes made with different alkali contents. There exists a linear relationship between the effective dosage of LiNO3 in terms of Li2O/Na(2)Oeq molar ratio and the difference Lac-TAL, indicating a remarkable increase of Li2O/Na(2)Oeq with L,c.
    No preview · Article · Jan 2003 · Advances in Cement Research