EXPERIMENTAL EVALUATION OF PERFORMANCES OF DIFFERENT SOLUTIONS OF FINISHING FOR MASONRY BUILDINGS FOR DETERMINING DURABILITY

The components of the building envelopes have to provide performances of different types: it is supposed to resist to the weather agents, to have a good water vapor permeability in order to prevent some degradation phenomena, and to inhibit the capillary rising dampness. But it must also maintain all these features over the time, in other words it must have a high durability. The designers, when they have to choose finishing solutions, are put in front of very complex evaluations, with the aim of finding the most appropriate one, given the specific context stress factors. To provide a useful guide for those frequent situations, two Departments of University of Naples Federico II conducted combined tests in the laboratories and on the field, on four types of finishing solutions (plaster + painting) for tuff masonry, which is typical of Southern Italy. In the DICMAPI laboratory the specimens were subjected to tests of water absorption by capillarity, tests of water vapor permeability, tests of water absorption at a low pressure, and tests of accelerated aging in a QUV machine. The field assessments were carried out on 500 sampled buildings in the city of Naples, over 10 years of monitoring, showing the different behavior of the four types of selected specimens: for example, the characteristics of the finishing solutions of macroporous plaster + silicate paint and cement plaster + quartz paint have remained almost the same, without significant performance decay. The results could represent a good starting point for the creation of a useful handbook for designers of recovery interventions

Recyclability Process of Standard and Foamed Gypsum

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Crushed Bricks: Demolition Waste as a Sustainable Raw Material for Geopolymers

Demolition activity plays an important role in the total energy consumption of the construction industry in the European Union. The indiscriminate use of non-renewable raw materials, energy consumption, and unsustainable design has led to a redefinition of the criteria to ensure environmental protection. This article introduces an experimental plan that determines the viability of a new type of construction material, obtained from crushed brick waste, to be introduced into the construction market. The potential of crushed brick waste as a raw material in the production of building precast products, obtained by curing a geopolymeric blend at 60 °C for 3 days, has been exploited. Geopolymers represent an important alternative in reducing emissions and energy consumption, whilst, at the same time, achieving a considerable mechanical performance. The results obtained from this study show that the geopolymers produced from crushed brick were characterized by good properties in terms of open porosity, water absorption, mechanical strength, and surface resistance values when compared to building materials produced using traditional technologies

Fibre-reinforced lime-based mortars: A possible resource for ancient masonry restoration

In order to design binding materials able to historical buildings restoration, physical–mechanical properties and microstructure of fibre-reinforced lime-based hydraulic mortars, have been studied, in comparison with a reference hydraulic lime-based mortar with no addition. Fibre-reinforced mortars, even characterised by larger porosity and lower mechanical strength than the reference, pointed up a clear improvement in the post-cracking behaviour and, regardless of nature and concentration of fibres, turned from brittle materials to ductile materials. It was demonstrated that the addition of as low as 2% of glass fibres leads to a toughening of the mortar and jointly to an improvement of the flexural load

Hydraulicity and Mechanical Properties of Mortars Manufactured with a Commercial Zeolite

Further to a recent exploratory investigation on the possible use of cheap, commercially available, synthetic zeolites as pozzolanic addition to portland cement, the present study aims at characterizing a low-silica sodium zeolite, named Na-A, as possible component of hydraulic lime mortars. In order to evaluate the action played by the zeolite in developing hydraulicity and mechanical properties, three lime-zeolite mortars with different ratios of the two components were prepared and characterized in terms of compositional features and mechanical and physical properties. The pozzolanic activity of the zeolitic addition was also evaluated by measuring the amount of free lime in experimental pastes, as a function of ageing time. The main results worked out are: (a) zeolite addition gives rise to a clear benefit on compressive strengths of the hardened mortars; (b) hardening is rapid, as more than 60% of the final compressive strengths is developed after only 7 days; (c) lime/zeolite ratio does not affect to a great extent porosity and water absorption of the manufactured mortars; (d) mortars containing equal amounts of lime and zeolite show the best performances, either from a compositional point of view (absence of unreacted zeolite) or from mechanical and porosimetric properties, also in comparison to an analogous, non-zeolitic, commercial mortar

Fiber-reinforced lime-based mortars: Effect of zeolite addition

In a previous paper the authors demonstrated that adding glass fibers to hydraulic lime-based mortars leads to clear improvement in the post-cracking behavior. In order to enhance physical and mechanical performances of the above fiber reinforced mortars, the use of zeolitic addition was proposed. A phillipsite-rich tuff and a zeolite A [LTA] were selected and added in the mixtures. A significant decrease in open porosity and increase in mechanical behavior was achieved with each addition. In particular 20% of LTA produces an improvement of flexural and compressive strength up to 150% compared with fiber reinforced mortars without addition