Showing papers in "Bulletin of the International Association of Engineering Geology in 1984"

Rapport general@@@General report

Abstract: Les réformes “ NGP ” sont nées d’une combinaison de facteurs économiques, sociaux, politiques et technologiques. Les pays ayant choisi la NGP ont un trait commun : ils affirment que leur expérience de crises économiques et fiscales les a amenés à s’interroger sur l’efficacité des services publics et les moyens d’améliorer leur compétitivité. La polémique reste cependant ouverte quant à savoir si les « crises économiques et fiscales » constituent de vraies raisons ou sont des prétextes à fins politiques !

Influence of geological factors on soundness and abrasion resistance of road surface aggregates: A case study

Abstract: A study has been carried out on soudness and abrasion resistance of crushed-rock aggregates used in heavily trafficked road surfacings in Gauhati, a city situated in the State of Assam, India. The crushed-rock aggregates under study were obtained from Precambrian acid igneous rock outcrops in and around Gauhati. The grain, size and the volume of pore spaces were found to be the significant geological factors influencing soundness and abrasion resistance. The durability, in terms of resistance to weathering and resistance to wear, of the acid igneous rocks was found to increase with decrreasing grain size and decreasing volume of pore spaces.

Correlations entre les proprietes physico-mecaniques des roches et le comportement des granulats manufactures

Abstract: La revue des essais d'acceptation des granulats, quant a leur qualite mecanique ou leur resistance aux agents atmospheriques, montre qu'il existe de tres nombreux essais empiriques en usage dans le monde mais pratiquement aucun n'est employe universellement. Dans cette communication il est passe en revue les divers modes de sollicitation imposes au granulat depuis sa production en carriere jusqu'a son emploi, en se referant notamment aux principes de la comminution. Cette etude, appliquee a divers types de roche (sedimentaire, metamorphique, ignee) dont les âges varient de l'Ordovicien au Miocene, montre en particulier que leur resistance en tension ou compression et leur perte de resistance due a la saturation en eau sont des indices significatifs de comportement si on les compare aux resultats des essais Los Angeles, Deval et Micro-Deval. Ainsi il est recommande d'appliquer les essais conventionnels de mecanique des roches aux granulats avant ou durant la mise en exploitation de carrieres. L'analyse de ces resultats, en parallele avec ceux des essais d'acceptation conventionnels, permettront d'ameliorer les previsions de leur comportement et eventuellement d'accepter des granulats juges marginaux et qui auraient ete refuses selon les normes actuelles. In this paper the different stresses which are applied to the aggregates during the laboratory testing procedures are discussed. Sedimentary, metamorphic and igneous rocks are considered and their age is from Ordovician to Miocene. Very good correlations are observed between compressive or tensile strength and Los Angeles, Deval and Micro-Deval test results; these correlations are explained by rock mechanics and comminution principles. Therefore, the authors suggest to realize systematically conventional rock mechanics tests on rock samples from the quarries to optimize the utilization of marginal aggregates.

Prediction of aggregate and pavement polishing

Abstract: Pavement life is determined by structural performance and degradation of the properties controlling wet friction between tires and pavement. Expulsion of the water from the interface is controlled by aggregate size, binder and mix design. Friction develops where most of the water has been displaced and depends on aggregate microtexture. Traffic reduces this fine texture, but the polishing is not a simple, continuous process. During certain periods the process reverses. Dust and other contaminants further complicate the process. Laboratory machines and procedures are described, which attempt to duplicate the process. Results are presented and the utility of the procedures for pavement management systems is discussed.

Relations between petrography and the aggregate properties of icelandic rocks

Abstract: Research work and field experience show that in Iceland aggregate properties and petrography are usually closely related. All rocks are volcanic, and the main types are basalt, rhyolite and hyaloclastite (consolidated tuffs). Unaltered basalt has in most respects high qualities, but impact and abrasion strength, durability and other propertis diminish rapidly with increased alteration. Porosity has an influence on the wear of road surfaces, but in other relations, porous and fresh basalt lava is advisable. Rhyolite can cause damage in concrete by alkali-aggregate reaction, and overall, both rhyolite and hyaloclastite have worse properties than basalt.

The use of the sand-blast test to determine rock durability

Abstract: The suitability of the sand-blast test to assess resistance of hard rocks against abrasion is investigated for eight different rock types. The test provides a good discrimination between different types of hard rock and is also sensitive to anisotropy in rock materials. A microscope study of the result of the impact of sand particles on the rock surface has been made in order to determine the applicability of the test to practical circumstances. Volume loss due to sand-blasting on hard rocks shows a correlation with tensile strength.

L'essai au bleu de methylene turbidimetrique

Abstract: L'essai au bleu classique qui connait une rapide diffusion et qui figure desormais dans de nombreux documents reglementaires francais, s'applique cependant mal aux materiaux relativement propres: gravillons, sables a beton hydraulique, ... L'essai decrit dans cette communication permettra de caracteriser les argiles des granulats quand elles sont presentes en faible quantite. Il est fonde sur deux phenomenes: - D'une part, la turbidite, devant traduire en premiere approximation la surface developpee par les particules en suspension, d'ou le nom de tubbidimetrique. - D'autre part, les modifications des spectres d'absorption lumineuse lorsque les molecules de bleu passent de l'etat libre a l'etat adsorbe. Ce phenomene constitue un moyen optique commode pour determiner le degre d'adsorption que subit une quantite donnee de ce colorant mise en presence d'une surface minerale. On mesure de cette maniere la partie active de la surface developpee.

Climate and the durability of South African road aggregates

Abstract: The absence of noteworthy unconsolidated fluviatile deposits, and the complete absence of unconsolidated glacial deposits can be explained from the South African geological history and topography. Apart from the crushing of fresh rock, South African road “gravel” and “sand” therefore have to be obtained from weathered rock. The use of such aggregates involves the risk that they may deteriorate below the design standards because weathering does not cease when the aggregate is removed from its source; indeed, the rate of weathering mostly increases after the aggregate has been placed in the pavement. Assessing the durability of the aggregate is therefore a primary requirement during selection. The durability of an aggregate, which differs according to the pavement layer in which it is used, depends on the petrological type of the material, of which quartz is an important indicator. Durability also depends on environment. Of the environmental conditions that control weathering, climate is the most important. South Africa's climate varies from extremely arid to subtropical-humid with either summer or winter rainfall. These widely different conditions have been accommodated in an expression known as the Weinert N-value which is a ratio of the computed evaporation during the warmest month (EJ) to the annual precipitation (Pa). It reads: $$N = \frac{{12 E_J }}{{P_a }}$$

Valorisation routiere des tufs d'encroutements en Algerie

Abstract: En Algerie, depuis une trentaine d'annees des milliers de kilometres de routes economiques de desenclavement, peu circulees, ont ete realises, dans l'ensemble avec succes, en tufs d'encroutements calcaires dans les zones sub-humides et semi-arides (de 600 a 100 mm de pluie par an) et en tufs d'encroutements gypseux ou gypso-calcaires en zone saharienne aride (moins de 100 mm de pluie par an). Mais, maintenant, le trafic y devient plus dense et surtout plus lourd, du fait de l'industrialisation progressive de l'Arriere-Pays, alors que les chaussees nouvelles doivent rester “economiques”. Les tufs d'encroutements paraissent pouvoir encore fournir une solution acceptable, sans utilisation de liants, a condition de choisir preferentiellement des encroutements typiques a croute dure ou a nodules, et de s'assurer que dans les assises de chaussee humides, la portance hivernale reste suffisante.

A reexamination of specification parameters for sandy soil roadbase materials

Abstract: Red sandy soils from the north-west of Western Australia have been used for construction of local roads and some arterial roads, in some cases with a sprayed bituminous seal. The comparisons of the results of different soil test methods and an assessment of their effectiveness as indicators of performance was done by examining soil test reports made by the Main Roads Department, Western Australia, in the period 1980 to 1981, and by the laboratory examination of samples of sand to which could be assigned some description of their performance and behaviour when used as road construction materials.

Quality variations in whin sill aggregates from Northumberland, England

Abstract: The Whin Sill is a dolerite intrusion with extensive outcrops in North East England. Quarries in the sill, provide the bulk of the crushed rock aggregates in the region suitable for roadstone. The dolerite is generally of high strength and little affected by weathering and thus yields high quality aggregates. At some quarries, however, dolerite of poor quality, locally known as “Woodhead”, is found. The “Woodhead” material differs from the normal dolerite is having a distinctive colour, lower strength and higher porosity. It can be shown that the material is produced by hydrothermal alterations related to calcite veining. Inclusion of Woodhead material in aggregates from one quarry lead to their rejection by a Local Authority and, as it proved impossible to separate the poorer material, the quarry closed. Quality variations have been determined by a range of standard tests. Test results can be related to petrographic indices determined by quantitative thin-section analyses.

Aggregates in Hong Kong

Abstract: Hong Kong, with a land area of only 1050 sq km and a population of cover 5 million, has developed rapidly in the past 30 years. The Paper reviews the history of quarrying in this land-scarce Territory and provides information on the distribution, operation and control of quarries. It describes the private quarries, government quarries, site crushers and importation of aggregates, and it outlines the planning for future quarries. Information is given on the types, uses and properties of the granite aggregates.

Marginal aggregates for highway pavements

Abstract: Marginal aggregates have been used to a very limited extent in the construction of embankments and highway pavement structures. However, the State of Florida has successfully utilized relatively poor limestones for base course construction. It has been observed that limerock bases increase in strength with ageing. A study of this phenomena revealed that Sparry Calcite cementation and drying during ageing produced strength gains as high as 100 per cent. Investigations into moisture effects and behavior of a dense graded shale aggregate indicated strength losses due to moisture content fluctuation similar to that of good limestone aggregate. A structural equivalency of 1,4∶1,0 was obtained for shale and limestone base courses.

Role des caracteristiques physico-mecaniques des granulats sur la resistance en compression de betons a tres haute resistance

Abstract: La realisation de structures tres elevees en beton devient de plus en plus frequente et ceci impose la mise au point de betons a tres haute resistance (100 MPa et plus). Cette nouvelle orientation conduit a tenir compte des proprietes mecaniques des granulats alors que dans le passe, les etudes portaient surtout sur les pâtes, les granulats n'etant soumis qu'a des tests d'acceptation generaux.

Progress in the study of New Zealand aggregates

Abstract: Granular roadbases with surfacings of bitumen and crushed aggregate chippings can be used to sustain loadings in excess of 2×106 equivalent 8 tonne axles.

Quarrying of aggregates in and around gauhati: Impact on the environment

Abstract: The Gauhati city is situated in the northeastern part of India. Since the late 1960's Gauhati has been undergoin massive development with construction of innumerable buildings, roads and pavements leading to a huge demand for construction materials. Consequently, aggregate quarries have muschroomed on hillslopes in and around Gauhati, Unplanned quarrying activities on hillslopes have brought about the problem of aesthetic degradation and slope failure. This paper highlight these problems and suggests corrective and preventive measures for preservation of the beauty of the natural landscape and stability of the hill slopes.

Assessment of a microgranite source rock for use in concrete

Abstract: A microgranite, showing varying degrees of weathering with depth, has been investigated as a source of concrete aggregate for dam construction. Diamond drilled cores and percussion drilled samples, taken to 40 m depth, were used for mineralogical, petrological, and methylene blue dye adsorption (MBA) studies and for measurement of drying shrinkage in order to assess the influence of deleterious secondary minerals, largely swelling clays, on the dimensional stability of the rock.

Statistical methods of aggregate durability evaluation

Abstract: The advent of microcumputers and access to sophisticated statistical software packages allows the researcher unprecendented opportunities to evaluate his data. In aggregate research, it allows the comparison of basic aggregate properties with empirical tests often used in specifications of aggregate quality.

A simplified approach for mix design based on shape factors of coarse aggregates

Abstract: The stability of granular materials and bituminous mixes increases with increase in dry density or decrease in voids in the mix. Therefore the proportions of materials in the mix are designed to obtain a desired gradation which yields maximum density.

The pumice aggregates of Lipari Island (Aeolian Isles-Italy)

Abstract: In the Island of Lipari (Aeolian Archipelago) there is a large pumice deposit. The pumice is exploited in an open-cast mine through mechanical means and taken to crushing and screening plants. Aggregates for urban construction, gravel and powder are obtained. The aggregates are used in the manufacture of light concrete. Nowadays the possibility of using pumice aggregates in order to obtain light structural concrete is being studied.

Slurry seal texture as affected by aggregate gradation

Abstract: Although slurry seal has been used since the 1950s, consistently successful application has been difficult in achieving both durable and skid-resistant slurry seal. This paper presents the results of a study dealing with the effects of aggregate gradation on the surface texture which directly affects the skid-resistance of a slurry seal.

A geological approach to traditional and alternative aggregates in the Netherlands

Abstract: In the Netherlands aggregates are mainly used for construction materials. Because of the almost total absence of hard-rock outcrops in this country, all of the aggregates derive from unconsolidated deposits. This article reviews the distribution, provenance, depositional environment, composition and exploitation of the main traditional aggregates in The Netherlands and in the Dutch sector of the North Sea. Most of this information is provided by the Quarternary geological history of the North Sea Basin in which this country is situated. Attention is also paid to the present and possible future application of alternative aggregates in The Netherlands.

Recherches sur les argiles Egyptiennes pour la production de granulats legers

Abstract: Dans certains pays ou de graves problemes paraissent tres difficiles a resoudre, par suite de l'absence de graviers naturels, le developpement de la construction des bâtiments a partir de betons legers presente une option tres interessante.

Inventory of aggregates in an expanding urban area

Abstract: Faced with a potential shortage of aggregate, the Minnesota Department of Transportation funded a study to inventory the aggregates in four pilot areas of the state and compare it with the estimated requirements in these areas. Based on the results of the study, several methods were suggested to enhance the aggregate supply in these areas. The aggregate resources in the four pilot areas were determined by analyzing the geology of the deposits, both natural aggregate and crushed rock. In addition, reserves in permitted properties were determined using a questionnaire that was given to each quarry operator in these areas. Permitted properties were defined as those for which permits have been issued by the government unit having jurisdiction. Analysis of the questionnaire date was supplemented with interviews of county and state highway department personnel and local planning agencies. Aggregate demand in the four areas was determined from national and county models of demand. Computer-aided multiple regression models defined the relationships between aggregate demand and construction of public and private facilities, ratio of non-metal to metal construction products, and the price of aggregate. Four methods were suggested for enhancing the aggregate supply. These included the definition of quantity and quality of aggregate in the vicinity of urban areas, improvement in beneficiation techniques to maximize the utilization of mined material, development of end-use specifications to permit maximum use of lower grade reserves and of recycled pavements, and revision of land use regulations to prevent the loss of aggregate reserves to urban sprawl.

Les betons de demolition source de granulats

Abstract: La consommation de granulats en France malgre la conjoncture demeure importante. L'ouverture de nouvelles gravieres se heurte a une reglementation plus severe et a la reticence des populations.

Quantitative petrographic analysis of aggregate

Abstract: Petrographic properties of an aggregate particle determine to a large extent how it will behave in service—its resistance to frost, wear and impact. An estimate of alkali reactivity and skid resistance can also be made. Several provinces in Canada use a variance of “Petrographic Number” determination, which gives a quantitative assessment of the quality of the aggregate.

Influence de la petrographie sur les caracteristiques physiques et mecaniques de granulats calcaires de lorraine

Abstract: L'etude concerne des calcaires de la region de Nancy, choisis pour leur variabilite petrographique: calcaires construits a polypiers, calcaires oolithique et micritique. Ces roches sont caracterisees par l'etude, au Microscope Electronique a Balayage, de leur porosite et de leur texture, par la mesure de celerite des ondes elastiques et de l'indice de qualite. Des essais mecaniques de compression controlee sont egalement realises. Les granulats issus de ces roches sont soumis a des essais Los Angeles et Microdeval. Les resultats de tous ces essais sont correles avec l'analyse au Microscope Electronique a Balayage. On compare egalement les etats de surface du granulat avant et apres essai mecanique, ainsi que le mode de rupture des grains.

Utilisation de la photographie de moire pour mesurer l'usure des granulats dans les couches superficielles de chaussees

Abstract: L'auteur decrit une methode rapide et non destructrice de suivi et de mesure de l'evolution de la forme des granulats incorpores dans des couches superficielles de chaussees.

A comparison of particle shape characteristics of crushed basalt and granite rocks

Abstract: There is an opinion that the shape of comminuted particles first of all depends on: a) natural properties of the rock, and b) manner of rock crushing. The paper presents results of investigation relating to the first of above questions. The samples both granite and basalt rocks, taken from different deposits, were crushed in the same way. The rocks to be crushed were characterized by structure of mineral composition and some physical properties. Particles produced by crushing were characterized by three shape coefficients. These characteristics were analysed comparatively in the context of rock properties and particle diameter. From the analysis there is no evident relation between shape of particles and rock characteristics.

The performance of aggregates in a single surface dressing, subjected to wear by studded tyres

Abstract: The performance of aggregates in a single surface dressing, subjected to wear by studded tyres