Data management using building information modeling for chemical building products

This paper shows the innovative solution based on BIM technology proposed for the digitalization of chemical products for buildings, focusing particularly on admixtures for concrete and products for restoration of existing buildings. The first step is leading the prospective buyer from his necessity to the selection of proper solution; the decisional process, that is based on the Fault Tree Analysis, starts from some generic questions, whose answers combined with themselves give the appropriate mix design in according to UNI EN 934-2 for concrete or the correct product and the prescription specifications for the other cases. Thanks to the digitalization of information made possible by the BIM process, established the correct product, it is now possible to define the products attributes necessary to inform the specific stakeholders and to import them to digital model in order to reduce the inaccuracies during the constructive phases and to draw a guideline for the eventual restoration

Chloride Diffusion in Concrete Protected with a Silane-Based Corrosion Inhibitor

One of the most important parameters concerning durability is undoubtedly represented by cement matrix resistance to chloride diffusion in environments where reinforced concrete structures are exposed to the corrosion risk induced by marine environment or de-icing salts. This paper deals with protection from chloride ingress by a silane-based surface-applied corrosion inhibitor. Results indicated that the corrosion inhibitor (CI) allows to reduce the penetration of chloride significantly compared to untreated specimens, independently of w/c, cement type, and dosage. Reduction of chloride diffusion coefficient (Dnssn) measured by an accelerated test in treated concrete was in the range 30–60%. Natural chloride diffusion test values indicate a sharp decrease in apparent diffusion coefficient (Dapp) equal to about 75% when concrete is protected by CI. Mechanism of action of CI in slowing down the chloride penetration inside the cement matrix is basically due to the water repellent effect as confirmed by data of concrete bulk electrical resistivity

Influence of Lithium Carbonate and Sodium Carbonate on Physical and Elastic Properties and on Carbonation Resistance of Calcium Sulphoaluminate-Based Mortars

In this study, three different hardening accelerating admixtures (sodium carbonate, lithium carbonate and a blend of sodium and lithium carbonates) were employed to prepare calcium sulphoaluminate cement-based mortars. The workability, setting times, entrapped air, elasto-mechanical properties such as compressive strength and dynamic modulus of elasticity, free shrinkage, water absorption and carbonation rate were measured and mercury intrusion porosimetry were also performed. Experimental results show that a mixture of lithium carbonate and sodium carbonate acts as a hardening accelerating admixture, improving the early-age strength and promoting a remarkable pore structure refinement. Finally, sodium carbonate also reduces the water absorption, the carbonation rate and the shrinkage of mortars without affecting the setting times and the workability

Carbonation of sustainable Portland-free CSA-based mortars manufactured with lithium and sodium carbonates

One of the most significant problem due to the calcium sulphoaluminate cement is the poor resistance to penetration of carbon dioxide. The aim of this study is to investigate the positive influences of lithium carbonate and sodium carbonate against the carbonation of sustainable mortars without Portland cement, manufactured with cal-cium sulphoaluminate, anhydrite and supplementary cementitious materials. In order to better define the behavior of these accelerator admixtures, several rheological, elasto-mechanical and physical properties like compressive strength,free shrinkage and dy-namic modulus of elasticity, have been investigated. Experimental results show that the addition of lithium carbonate and sodium carbonate could be used to reduce the depth of carbonation without affecting the other above-mentioned properties

Miglioramento strutturale ed energetico di edifici in muratura. Studio di intonaci armati termoisolanti privi di cemento

L’articolo tratta dello sviluppo di un innovativo intonaco strutturale alleggerito privo di cemento Portland in grado di migliorare la risposta sismica e l’efficienza energetica di edifici in muratura di pietra di scarsa qualità. Al fine di garantire la compatibilità elasto-meccanica con le murature storiche in pietra, l’intonaco deve esibire una resistenza a compressione a 28 giorni prossima a 8 MPa e, allo stesso tempo, deve possedere una ridotta massa volumica, non superiore a 1000 kg/m3, per poter incrementare la resistenza termica delle murature. Tali obiettivi sono antitetici tra loro e risultano di difficile ottenimento quando si impiegano leganti totalmente privi di cemento Portland. Lo studio ha indagato il possibile uso sia di miscele a base di loppa d’altoforno e calce idrata sia di leganti ad attivazione alcalina. Per poter realizzare intonaci alleggeriti l’aggregato naturale è stato sostituito parzialmente o totalmente con aggregati leggeri a base di vetro espanso. I risultati ottenuti indicano che l’intonaco a base di loppa d’altoforno attivata alcalinamente realizzata esclusivamente con aggregati leggeri e con l’aggiunta di un additivo aerante è in grado di garantire resistenze a compressione a 28 giorni prossime a 8 MPa e una conducibilità termica pari a 0.35 W/mK, ottenuta grazie alla ridotta massa volumica (700 kg/m3). Inoltre, grazie all’aggiunta di metilcellulosa, amido, fibre polipropileniche e di un additivo riduttore del ritiro, è stato possibile ottenere malte caratterizzate da un’ottima adesione, dall’assenza di microfessure e di distacchi dal supporto. Al contrario, le miscele di loppa d’altoforno e calce idrata non garantiscono il raggiungimento dei requisiti meccanici richiesti, evidenziando resistenze a compressione nell’ordine dei 2 MPa.The article focus on the development of a one-part alkali activated slag-based lightweight plaster for seismic retrofitting and energy upgrading of poor-quality stone masonry buildings. Two different alkali activated mortars were manufactured by using expanded glass aggregates and air entraining agent in order to guarantee the mechanical compatibility with historic stone walls (28-day compressive strength close to 8 MPa) and, at the same time, a low thermal conductivity by means of a low specific mass (< 1000 kg/m3). Experimental results evidenced that alkali activated plasters are able to provide a 28-day compressive strength equal to 8 MPa and a thermal conductivity of 0.35 W/mK due to density close to 700 kg/m3. Furthermore, by using methylcellulose (MC), modified starch (MS), polypropylene fibers and shrinkage reducing admixture (SRA), the shrinkage of mortars was strongly reduced and excellent adhesion to the substrate, absence of micro-cracks and detachments were achieved