Search results for "Pozzo"

Morteros hidràulicos para enlucidos: caracterizaciòn mecànica y fìsica de remedios tradicionales y productos industriales

2009

An integrated analytical approach to define the compositional and textural features of mortars used in the underwater archaeological site of castrum …

2019

This paper aims to carry out an archaeometric characterization of mortar samples taken from an underwater environment. The fishpond of the archaeological site of Castrum Novum (Santa Marinella, Rome, Italy) was chosen as a pilot site for experimentation. The masonry structures reached the maximum thickness at the apex of the fishpond (4.70 m) and consisted of a concrete conglomerate composed of slightly rough stones of medium size bound with non-hydraulic mortar. After sampling, for a complete characterization of selected mortar fragments, different and complementary techniques (stereomicroscopy, polarizing optical microscopy, and X-ray powder diffraction analysis) were carried out in order…

Inconsistencies in the pozzolanic strength activity index (SAI) for silica fume according to EN and ASTM

2014

Published version of an article in the journal: Materials and Structures. Also available from the publisher at: http://dx.doi.org/10.1617/s11527-014-0457-6 Open Access New supplementary cementitious materials claimed to possess pozzolan properties emerge frequently. This development is driven both by economic and environmental pressures. Properties of new materials are compared with those of materials already well known, such as silica fume. Several test methods are standardized for making such comparisons, regulated by both European (EN) and American (ASTM) standards. Standardization indicates that procedures are secured to make comparisons valid and informative. In this article the sensit…

Retention of alkali ions by hydrated low-pH cements: Mechanism and Na+/K+ selectivity

2013

Low-pH cements, also referred to as low-alkalinity cements, can be designed by replacing significant amounts of Portland cement by pozzolanic materials. Their pore solution is characterized by a pH near 11, and an alkali concentration much lower than that of Portland cement. This work investigates the retention of sodium and potassium by a hydrated low-pH cement comprising 60% Portland cement and 40% silica fume. It is shown that sorption of potassium is higher than that of sodium and mainly results from counterion charge balancing of the C-S-H negative surface charge. To explain the greater retention of potassium compared to sodium, it is postulated that potassium, unlike sodium, may enter…

From the “Sacred Theatres” of Andrea Pozzo to the International Truncated Calotte: History and Representation of the Immacolatella Church’s Tribune i…

2022

The contribution, divided between history and representation, aims to analyse the design genesis and the sources used by the architect Giovanni Amico for the modernization of the Immacolatella church’s tribune in Trapani (since 1732). The church is devoid of studies and surveys with digital instrumentation but its unique compositional characteristics, which exploit the theme of the manipulation of space and light for scenographic and liturgical purposes, require in-depth analysis. The solution applied to the church tribune combines different compositional themes linked to the Roman design world and in particular by Andrea Pozzo in relation to the “sacred theatres” produced for the Jesuits a…

Effect of some additives on the reactions in fly ASH-Ca(OH)2system

2004

Differential thermal analysis and thermogravimetry were used to evaluate the effect of some additives, such as CaSO4, CaCl2 and silica fume amorphous silica from ferrosilicon synthesis on the mechanism and kinetics of reactions occurring in fly ash-Ca(OH)2 system. The accelerating role of these additives was demonstrated from the data relating to Ca(OH)2 consumption in hydrated pastes, determined by TG measurements.

Analysis of the chemical and microstructural modifications effects on the hydro-mechanical behaviour of a lime-treated clay

2019

The paper presents the results of a characterization of kinetic characteristics of pozzolanic reaction with the aim to investigate the time-dependent modification of clay properties as a consequence of mixing with lime. Results of chemical analyses are in agreement with the increase of mechanical properties and with the observed microstructure modifications up to one year of curing time. The rate of development of pozzolanic reactions seems to be almost constant while the time required for their completion is dependent on the lime content. Pozzolanic products are responsible for the time reduction of swelling strain upon saturation as well as for the increases of yielding stress, stiffness …

La arquitectura de la portada y retablos de San Miguel Arcángel de Burjassot. Reflejo de los modelos figurativos de A. Pozzo

2005

Friar-architects carried out important projects in the Valencia area. These monks, who combined architectural with spiritual labors, accomplished works in which they knew how to combine tradition with new architectural tendencies. The church of St. Michael Archangel of Burjassot by Friar Francisco de Santa Bárbara, provides the chance to study this constructive phenomenon in relation to its doorway and twin altarpieces at the crossing. Without doubt, these structures demonstrate the direct influence of the Jesuit Andrea Pozzo's treatise <i>Perspectiva Pictorum et Architectorum</i> (1693-1700), which had a broad repercussion in the Valencia region.<br><br>La actividad…

On the hydro-mechanical behaviour of a lime-treated embankment during wetting and drying cycles

2018

Abstract The paper presents some experimental results obtained on samples extracted from a full-scale embankment obtained by compacting a lime-treated clayey soil. A comprehensive test programme was carried out in order to highlight the improvement of mechanical behaviour induced by lime treatment as well as to assess the durability of the improved material, which may be affected by severe seasonal wetting and drying cycles. Direct shear tests, triaxial compression tests, swelling potential measurement and oedometric tests were performed on samples cured in controlled environmental conditions for at least 18 months. Wetting and drying cycles were applied in a very wide range of suction valu…

Physical and mechanical properties of sustainable hydraulic mortar based on marble slurry with waste glass

2021

This paper aims to propose and characterize a sustainable hydraulic mortar entirely obtained by the reuse of waste materials, with marble slurry coming from quarries in the north-western Sicily and glass powder coming from a waste collection plant in Marsala (Province of Trapani). The first was used as raw material to produce the mortar binder by a kilning and slaking process, while the second was used as a pozzolanic additive. The chemical and morphological characterization of the marble slurry was done by XRD, FTIR, STA and SEM analyses. Glass powder was analyzed through particle size distribution measurements, XRD and standard pozzolanic tests. Hydraulic mortars constituted by slaked lim…