Criteria for Laboratory Studies on Fine Soils Treated with Lime

When selecting the appropriate materials for constructing road infrastructures, an important way for minimizing both the economical and environmental impact is to make use of lime for treating those natural soils that, involved in the earthwork for opening road fences, are not suitable, as they are in nature, to fulfill the specific requirements for being used as part of road construction, such as road embankments (including the capping layer) or the improved subgrade or, again, the sub-formation. From this point of view, the treatment of fine soils with lime (if needed, with lime and cement) can be considered as one of the main measures for preserving the natural environment since it fulfi…

Definition of a laboratory optimization protocol for road bitumen improved with recycled tire rubber

Abstract Bearing in mind the need to answer one of the most frequent needs for civil construction, in general, and major project such as road infrastructures in particular, this paper presents the results of a laboratory experimental study in order to evaluate the performance improvement that is possible to achieve when modifying road bitumen with CRM (Crumb Rubber Modifier) from discarded tire rubber (TR), using a Wet Process. The environmental advantage is double, since the aim of the research is to obtain high performance road bitumen thanks to the re-use of a discarded material, such as the rubber tires, which otherwise would be dumped in scrap-yard. In particular, this experimental stu…

Prova di campo per i lavori di trattamento delle terre argillose con calce per lavori stradali e ferroviari [Field test of lime treatment of clayey soils for railways and road works]

Si presentano i risultati di una prova di campo svolta su un rilevato sperimentale appositamente progettato e costruito per le finalità del trattamento con calce delle terre argillose. Tale prova di campo è stata sviluppata nell’ambito dei lavori di ammodernamento di una infrastruttura di grande comunicazione in Sicilia, per consentire il reimpiego delle argille di risulta dagli scavi previsti in progetti nella costruzione delle parti in rilevato della stessa. Il programma sperimentale messo a punto si è pertanto concentrato sull’identificazione e la caratterizzazione geotecnica delle argille di scavo al fine di definire le modalità esecutive del loro trattamento con calce. Attraverso le pr…

Evaluation of the laboratory prediction of surface properties of bituminous mixtures. Construction and Building Materials. Volume 23. Issue 2. Elsevier Ltd, Amsterdam. ISSN: 0950-0618 pp. 943–952

An experimental and analytical investigation was carried out both in laboratory and in situ on wearing courses. The approach presented in this paper aims to predict the in situ density and surface properties of bituminous layers, during the phase of mix design in laboratory. Therefore, the main attempt of this study is to identify, amongst the commonly available laboratory equipments, the most adequate for producing specimens that, used for carrying out simple and reliable laboratory test, allow the prediction of the surface characteristics of the mixture as laid on site. This is done by comparing the data collected from an experimental site with those calculated from laboratory specimens c…

Impatto delle Norme Funzionali e Geometriche per la Costruzione delle Strade sulla qualità dei progetti ed orientamenti per la loro revisione

PREVISIONE DA PROVE DI LABORATORIO DELLA COMPATTEZZA DEGLI STRATI BITUMINOSI IN OPERA.

Conglomerati bituminosi migliorati con materie polimeriche di scarto

Criteri e studi di progetto per il trattamento con calce dei terreni fini di scavo

Evaluation of the laboratory prediction of surface properties of bituminous mixtures

Abstract An experimental and analytical investigation was carried out both in laboratory and in situ on wearing courses. The approach presented in this paper aims to predict the in situ density and surface properties of bituminous layers, during the phase of mix design in laboratory. Therefore, the main attempt of this study is to identify, amongst the commonly available laboratory equipments, the most adequate for producing specimens that, used for carrying out simple and reliable laboratory test, allow the prediction of the surface characteristics of the mixture as laid on site. This is done by comparing the data collected from an experimental site with those calculated from laboratory sp…

TRATTAMENTO CON CALCE DEI TERRENI ARGILLOSI: STATO ATTUALE DELLA TECNICA

Experimental testing for physical and functional characterization of wearing courses

Tecniche esecutive e controllo di qualità dei lavori in terra-calce

Sebbene si tratti di una tecnica largamente sperimentata da diversi anni, ormai, e sviluppata per impieghi differenti che vanno dalla realizzazione di rilevati (stradali, ferroviari ed aeroportuali) alla formazione di strati di sottofondazione ed anche di fondazione delle pavimentazioni, la stabilizzazione con calce (o con calce e cemento), per essere applicata secondo le attuali regole dell’arte, richiede: · conoscenze tecniche comprovate negli studi di progetto delle miscele e nell’adeguamento della composizione delle stesse, in corso d’opera, in relazione alla variabilità dei fattori di cantiere (contenuto naturale d’acqua dei terreni, condizioni climatiche, dispersioni di dosaggio); · m…

Costruzione dei rilevati stradali e ferroviari: valutazione delle metodologie di progetto delle terre trattate con calce

Nella costruzione delle opere civili e, soprattutto, delle infrastrutture di trasporto, elemento qualificante per la minimizzazione degli impatti economici ed ambientali è l’adozione del trattamento con calce dei terreni argillosi di scavo, di per sé non idonei ad essere impiegati nei manufatti in terra, e la loro utilizzazione - previo trattamento con calce, appunto - per la costruzione di rilevati ed altre opere in terra. La tecnica del trattamento con calce delle terre argillose permette di ottenere diversi vantaggi di ordine tecnico, economico ed ambientale. I progressi tecnologici conseguiti negli ultimi decenni, particolarmente per quanto riguarda gli studi di progetto, i mezzi di can…

Design Procedures for Soil-Lime Stabilization for Road and Railway Embankments. Part 2-Experimental Validation

AbstractAs detailed in Part 1, the most common Italian Technical Specifications refer to different design methodologies for design of lime-soil mixtures, some being quite different from those internationally adopted. Therefore, it seemed appropriate to the Authors to compare these methodologies, via a wide experimental program.It is shown that the Italian methodology of the National Road Agency is different not only from those used in Italy, but also from the main international standards. The experimental results highlight that a revision of that methodology is needed in order to bring it into line with what is prescribed by the European standard.

PROPRIETÀ STRUTTURALI DI CONGLOMERATI BITUMINOSI MIGLIORATI CON PLASTICHE POST-USO

PG dei bitumi stradali per il territorio italiano

L’ARTICOLO SINTETIZZA IL LAVORO DI RICERCA SVOLTO DALL’UNIVERSITÀ DI PALERMO PER DEFINIRE - SU BASE TERRITORIALE NAZIONALE - LE TEMPERATURE CARATTERISTICHE DETERMINANTI PER LA QUALIFICAZIONE DEI BITUMI, CONFORMEMENTE ALLE SPECIFICHE SUPERPAVE. NE SONO DERIVATE CARTE TEMATICHE DELLE TEMPERATURE MASSIME E MINIME DI PROGETTO DELLE PAVIMENTAZIONI STRADALI CHE I TECNICI POTRANNO UTILIZZARE PER LA SELEZIONE DEI LEGANTI BITUMINOSI.

Conglomerati bituminosi additivati.

Design Procedures for Soil-Lime Stabilization for Road and Railway Embankments. Part 1-Review of Design Methods

AbstractWhen selecting the appropriate materials for constructing road infrastructures, an important way for minimizing both the economical and environmental impact is to make use of lime for treating soils that are not suitable for road or railways construction.Advances in lime stabilization technique allowed the successful use of this technique also for improving the bearing capacity of the subgrade, with noticeable savings on both aggregate and disposal charges.In this paper a review of internationally adopted design methods for soil-lime mixture is presented, in order to compare testing methods and requirements of the adopted criteria, as discussed in Part 2.

Effect of the construction process on the performances of asphalt paving mixes with crumb rubber from scrap tires

This paper presents the results of an experimental study on the use of CRM (Crumb Rubber Modifier) in bituminous mixtures for asphalt pavements, using a Dry Process. Employing experimental methods capable of ensuring that the mixtures obtained and the stress conditions that they undergo in pavements are representative, we clarify some aspects relating to the design and production of mixtures; we also show the effects of the bitumen-rubber interaction on mechanical performances (fatigue resistance and rutting). Among the various factors involved in manufacture, a particular investigation was carried out on the effects of asphalt content, mixing temperatures and mixture compaction. The experi…

EFFECT OF PROCESSING TEMPERATURE VARIATION ON STORAGE STABILITY OF TIRE RUBBER MODIFIED BINDERS

Tire Rubber Modified Binders (TR-MBs), produced through wet process and used worldwide (e.g. asphalt rubber), have been demonstrated to provide various benefits to pavements and, moreover, represent a good opportunity for recycling tire rubber. However, this technology is still struggling to be fully adopted in Europe, mainly because of the poor stability of TR-MBs during high temperature storage, which leads to high initial costs in modifying existing asphalt plants. No-agitation TR-MBs (also known as terminal blends) are proving to be a great option and their development could also be the key to spreading the use of tire rubber in paving applications in Europe. This paper aims to enrich t…