Weathering Research Papers - Academia.edu (original) (raw)

Abstract Inadequate and poorly maintained pavement markings are considered to be one of the largest contributing factors to fatal motor vehicle crashes. As a result, it is essential to apply the appropriate pavement marking material for... more

Abstract Inadequate and poorly maintained pavement markings are considered to be one of the largest contributing factors to fatal motor vehicle crashes. As a result, it is essential to apply the appropriate pavement marking material for all weather conditions in order to ...

A number of motored auger holes have been drilled in 2002 and 2006 in four sand-clay deposits preserved in dissolution pockets within the Dinantian limestones of the watershed north of the Vesdre valley. These deposits of unknown age are... more

A number of motored auger holes have been drilled in 2002 and 2006 in four sand-clay deposits preserved in dissolution pockets within the Dinantian limestones of the watershed north of the Vesdre valley. These deposits of unknown age are currently classified as (Tertiary) SBL in the new geological map of Wallonia. We present detailed lithostratigraphic logs of the deposits and describe the results of sedimentological and mineralogical analyses. In particular, K-Ar dating of neoformed Mn oxides found at the base of one augerhole at Rechain yielded ages ranging from Cenomanian to Santonian, allowing us to place the Rechain and Andrimont deposits within the early Late Cretaceous. This is fully consistent with their topographic location very close beneath the trace of the pre-Cretaceous erosion surface and makes them the westernmost remains of the Hergenrath Member of the Late Cretaceous Aachen Formation. To the west, the Magnee deposit is more "typical SBL", probably correspo...

Sediment geochemistry is a powerful tool to investigate earth surface processes because sediments record geochemical signatures of their provenance, generation, transport, deposition, and environmental conditions. A significant... more

Sediment geochemistry is a powerful tool to investigate earth surface processes because sediments record geochemical signatures of their provenance, generation, transport, deposition, and environmental conditions. A significant advancement in the technology of analytical geochemistry has made geochemical analyses of sediments more rapid and precise, which together provided an impetus to the study of sediment system. As a result, high-quality research papers on sediment geochemistry have been published during the last five years from India. A foreseeable growth of research and an increase in the publication are likely in the future because of the new setups of state-of the-art analytical instruments for geochemical research at various research and academic institutions in India. Here we are presenting the published important work on sediment geochemistry under three categories, i.e., weathering, erosion, deposition and provenance determination; sediment geochemistry as palaeoclimate proxy; and environmental geochemistry.

This paper reviews the research reported mostly in the last 10 years in the most common journals on the wood-cement composites field. The focused topics include: the problem of the compatibility (or not) between cement and woods, what... more

This paper reviews the research reported mostly in the last 10 years in the most common journals on the wood-cement composites field. The focused topics include: the problem of the compatibility (or not) between cement and woods, what causes it, ways of overcoming the problem; methods for manufacture and the properties exhibited by common wood-composites; special techniques to accelerate the curing of cement and to improve the properties of wood-cement composites; manufacture of nonwood vegetable raw materials-cement composites; durability against weathering and fungi; and construction materials. A discussion on the state-of-the-art is also presented. Dieser Artikel gibt einen Überblick über die Forschung der letzten 10 Jahre in den bekanntesten Zeitschriften, die über das Gebiet der Holz-Zement-Werkstoffe berichteten. Die konzentrierten Themen beinhalten: Das Problem der Kompatibilität oder Nicht-Kompatibilität zwischen Zement und Holz, was es verursacht und wie man es überwinden kann; Methoden zur Herstellung und die Eigenschaften, die bei üblichen Holz-Werkstoffen gefunden werden; spezielle Techniken, um die Aushärtung von Zement zu beschleunigen und die Eigenschaften von Holz-Zement-Werkstoffen zu verbessern; die Herstellung von Zement-Werkstoffen aus anderen Pflanzenrohmaterialien; Resistenz gegen Witterung und Pilze sowie Konstruktionsmaterialien. Eine Diskussion als Stand der Forschung wird ebenfalls präsentiert.

In southeastern Central African Republic the lateritic weathering mantles are capped by 2 to 5 m thick ferricretes, which previously formed under a seasonal tropical climate. The actual humid tropical climatic conditions result in the... more

In southeastern Central African Republic the lateritic weathering mantles are capped by 2 to 5 m thick ferricretes, which previously formed under a seasonal tropical climate. The actual humid tropical climatic conditions result in the biophysical disaggregation of the ferricretes everywhere the forest develop that lead to a soil formation composed of ferricrete relicts and ferruginous nodules embedded in a soft bioturbated micro-aggregated clay-ferruginous matrix. The potential effect of the biological activity (e.g., termites) on the soil and vegetation dynamics and therefore on the evolution of the previous consolidated ferricrete is discussed. Following its mechanical disaggregation by the forest tree roots, the ferricrete underwent a chemical degradation under the combined effect of hydration and redox conditions, which result from the biodegradation and oxidation of the organic matter. The transformation of the ferricrete into a soft bioturbated micro-aggregated clay-ferruginous soil matrix implies the hematite dissolution, and the kaolinite transformation into gibbsite, which may characterize a late "bauxitization" (secondary gibbsitization of kaolinite) of previous ferricrete profiles linked to a late Quaternary environmental (climate and vegetation) change. However, the geochemical and mineralogical patterns of the matrix not only reflect the geochemistry of the parental ferricrete but also depend on the physical transfers of quartz and heavy minerals from the lower horizons of the profile. Hence, the use of geochemical indexes such as Ti and/or Zr for mass balance calculations in the lateritic weathering profiles is precluded because these supposedly inert chemical elements are not simply accumulated by in situ chemical weathering process.

The petrographic and geochemical composition of the Dharla River sediments has been examined to infer their sediment type, degree of weathering, provenance, and tectonic settings. Petrographically the sediments are characterized by the... more

The petrographic and geochemical composition of the Dharla River sediments has been examined to infer their sediment type, degree of weathering, provenance, and tectonic settings. Petrographically the sediments are characterized by the high quartz content (64.97 to 74.24 wt%), followed by feldspar (7.04 to 15.20 wt%), mica (5.38 to 19.92 wt%), lithic fragment (3.46 to 8.14 wt%), and heavy minerals (1.98 to 6.94 wt%). Geochemical composition shows marked enrichment of SiO 2 (mean ~ 74.16%) and a strong negative correlation with the other major oxides because of quartz dilution. The Chemical index of alteration (CIA, 45.52 to 63.51); Plagioclase index of alteration (PIA, 43.13 to 66.55); W index (20.15 to 32.86) and Rb/Sr ratios (0.35 to 0.98) suggest low to moderate intensity of chemical weathering in the source area. Geochemical classifications of the studied samples show mostly litharenitic immature type of sediments also reflects high index of compositional variability (ICV, 0.96 to 1.72). The ternary diagrams of Al 2 O 3-(CaO + Na 2 O)-K 2 O (or A-CN-K) and of mafic rocks, felsic rocks and degree of weathering of the source rocks (or MFW) and several immobile trace element ratios (e.g. light rare earth element/heavy rare earth element or LREE

Soapstone is a main material used in Norwegian medieval stone architecture. It is a metamorphic, dense and durable stone, but like other stones, it is occasionally subject to severe weathering. This paper gives an overview of the core... more

Soapstone is a main material used in Norwegian medieval stone architecture. It is a metamorphic, dense and durable stone,
but like other stones, it is occasionally subject to severe weathering. This paper gives an overview of the core issues related to outdoor soapstone weathering in Norway and shows how the weathering has changed over time. First, objects that evidently weathered quite strongly during the Little Ice Age (14th–19th century), especially in the countryside, have now been relatively stable for a hundred years or more. Although a multitude of weathering processes might have been active, this could point to a higher frequency of damaging frost events in the Little Ice Age than at present. In the case of former ruins, the present stable condition might also be related to good roofing and less moisture in the masonry. Second, the weathering was in complex ways, often governed by changes in architectural design, influenced by air pollution in the cities from the late 19th century until the recent drastic reductions in SO2 emissions. Third, alkaline salts from Portland cement, sulfate from air pollution and some stones, as well as chloride from acid cleaning, greatly enhanced the salt load at many monuments in the 19th and 20th centuries, giving rise to severe weathering, especially at places where water leaks and damaging run-off have prevailed. This situation obviously continues to be problematic.

Tafoni and gnamma are cavernous weathering phenomena that have been extensively surveyed, discussed, and studied. From delicate, polygonal cells (2–4 mm) to huge circular pits (30 mþ), they develop in a variety of rock substrates,... more

Tafoni and gnamma are cavernous weathering phenomena that have been extensively surveyed, discussed, and studied.
From delicate, polygonal cells (2–4 mm) to huge circular pits (30 mþ), they develop in a variety of rock substrates, commonly in sandstone (tafoni) and granite (gnamma). Early research on their initiation and development was divisive, but current studies indicate polygenetic, differential weathering from intrinsic factors including hydrolysis, hydration of lithologic constituents, to extrinsic influences like moisture availability, insolation, and salinity. Increasingly, it is believed that complex, feedback cycles are responsible for their sigmoidal rates of development.

The book is a collection of 13 scientific articles presenting the problems of the weathering zone of anhydrite and gypsum rocks on the example of their exposures in western Ukraine, Poland, Spain, Canada and Russia. Most of the articles... more

The book is a collection of 13 scientific articles presenting the problems of the weathering zone of anhydrite and gypsum rocks on the example of their exposures in western Ukraine, Poland, Spain, Canada and Russia. Most of the articles are devoted to unusual forms of relief and associated caves, rare in the world, that are formed today as a result of the local increase in volume of the weathered rocks. Such forms (described in this book) are domes and hydration caves currently developing within anhydrites at Pisky near Lviv (Ukraine), as well as at Dingwall in Canada, and the so-called gypsum tumuli – developing in gypsum, near Sorbas in Spain. The book deals with various geomorphological, hydrogeological, microclimatic, petrographic, and speleological issues, as well as those related to the threats of active karst development. The articles were written in Polish, Ukrainian and English by 17 scientists from Poland, Ukraine and Germany.

tNovel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid par-ticles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) andnanosilica were synthesized via... more

tNovel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid par-ticles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) andnanosilica were synthesized via chemical oxidative and sol–gel polymerization techniques respectively.The prepared materials were characterized via (gel permeation chromatography (GPC), infra red (FT-IR), transmission electron microscope (TEM) and differential scanning calorimetry (DSC)). The binderused in this context is polyvinyl acetate (PVAc). Nanohybrid particles/PVAc emulsion composites (nHPsECs) were simply formed by individual mixing of the prepared neat PANI and nHPs of composition (1:1)with PVAc to produce the corresponding nanohybrid particles/PVAc emulsion composites EC1and EC2respectively. The chemical and basic properties including (acid and alkali resistance, adhesion, washabil-ity, gloss, opacity, whiteness, hardness, impact, and weathering) as well as the anticorrosion propertiesof the blank paint films and the paint films containing neat PANI and nHPs of different concentrations(5%, 10%, and 15%) were investigated and evaluated. The obtained experimental results revealed that thepresence of nHPs in the blank paint are highly enhanced both basic and anticorrosion properties of thecoated films.

The newly developed system presented in this paper is based on a three-step approach and on the probabilistic assessment of independently different failure mechanisms in a slope. First, the scheme classifies rock mass parameters in one or... more

The newly developed system presented in this paper is based on a three-step approach and on the probabilistic assessment of independently different failure mechanisms in a slope. First, the scheme classifies rock mass parameters in one or more exposures and allowance is made for weathering and excavation disturbance. This gives values for the parameters of importance to the mechanical behaviour of a slope in an imaginary, unweathered and undisturbed ‘reference’ rock mass. The third step is the assessment of the stability of the existing slope or any new slope in the reference rock mass, taking into account both method of excavation and future weathering. From the large quantity of data obtained in the field, the Slope Stability Probability Classification (SSPC) system has been proposed, based on the probabilities of different failure mechanisms occurring. Developed during 4 years of research in Falset, Tarragona province, Spain, it has been used with good results in Austria, South Africa, New Zealand and the Dutch Antilles.

The strength of a rock mass for foundation purposes is for a large part determined by the discontinuities in the rock mass. Numerical calculations of discontinuous rock masses prove often to be cumbersome and unreliable. Rock mass... more

The strength of a rock mass for foundation purposes is for a large part determined by the discontinuities in the rock mass. Numerical calculations of discontinuous rock masses prove often to be cumbersome and unreliable. Rock mass classification may be an equal or more reliable methodology. The Slope Stability Probability Classification (SSPC) system designed for slope stability may be used for this purpose. The system has been developed during four years of research in Falset, province Tarragona, Spain. The rock slope classification scheme assesses orientation dependent and orientation independent stability. The orientation independent stability assessment leads to a rock mass strength criterion based on classification data, e.g. intact rock strength, discontinuity spacing and discontinuity condition. The criterion is developed in the context of a slope stability classification system, however, there is no reason that the criterion is not also valid for the determination of rock mass strength for other purposes, such as foundations on a discontinuous rock mass. The results of the strength criterion are compared to the results of the ’modified Hoek-Brown strength criterion’ and to the rock mass strength as determined by Bieniawski’s classification system.

It is quite impossible to travel far in India without observing the remarkable ferruginous crust to which F. Buchanan in 1807 gave the name of laterite. In Indian peninsula it is a post-Cretaceous stratigraphic succession with polycyclic... more

It is quite impossible to travel far in India without observing the remarkable ferruginous crust to which F. Buchanan in 1807 gave the name of laterite. In Indian peninsula it is a post-Cretaceous stratigraphic succession with polycyclic nature of evolution which marks the unconformity with Recent Quaternary Alluvium. There are perennial problems and research gaps in the investigation of laterites in India as well as West Bengal – (1) defining, indentifying and classifying lateritic materials, (2) mode of formation of laterite and its other horizons, (3) determining the ages of laterites, (4) reliability of laterites as palaeoclimatic indicators, (5) identifying topographic requirements and pedo-geomorphic processes for laterite formation and (6) reconstructions of former lateritized landscapes. The formation of north – south lateritc cover (i.e. Rarh Bengal) on the Rajmahal Traps, Archaean granite – gneiss, Gondwana sedimentary, Paleogene gravels and Old Deltaic Alluvium is analyzed here to resolve the aforesaid problems and to depict the variable characteristics of laterites with special reference to its tectono – climatic evolution in northwest marginal part of the Bengal Basin. This paper reveals that the low-level secondary laterites (probably Pliocene – Early Pleistocene age) of Rarh Bengal are composed of heterogeneous iron – aluminum rich gravelly materials which were derived from the high-level primary laterites (probably Eocene – Miocene age) of Plateau since Paleogene Period by the peninsular river system, following the underlying structure of the Bengal Basin. Alongside the roles of drifting of Indian Plate, establishment of monsoon climate, neo-tectonic uplifts and re-lateritisation of ferruginous shelf deposits are determined here to unearth the palaeogenesis of primary and secondary laterites in West Bengal.

“Stone runs” is the Falklands vernacular term for openwork boulder accumulations, which include extensive blockstreams like the famous Darwin “stone-river” and associated features such as stone stripes. Since the early 20th century, they... more

“Stone runs” is the Falklands vernacular term for openwork boulder accumulations, which include extensive blockstreams like the famous Darwin “stone-river” and associated features such as stone stripes. Since the early 20th century, they have been interpreted as the product of a suite of periglacial processes, including frost-wedging, gelifluction, frost heave, frost-sorting and snowmelt runoff. Following a literature review, the results of recent field investigations of the valley-floor blockstreams of East Falkland are presented. Access to the internal structure of these forms provides evidence for the existence of a three-fold profile, with clear vertical size gradation presenting striking similarities with an inverted weathering profile. Micromorphological analyses, SEM, XRD, thin sections and grain-size analyses lead to the hypothesis of an alternative model of stone run formation. It is suggested that the material forming the stone run profile lato sensu (including the superficial pavement) is not of periglacial origin, but derives directly from the stripping and accumulation downslope of a regolith, possibly Tertiary in age and formed under subtropical or temperate conditions. The valley-floor stone runs should, therefore, be considered as complex polygenetic landforms that may have formed according to a six-stage scenario, including in situ chemical weathering, regolith stripping by mass movements, soil formation, further regolith stripping, downslope accumulation and matrix washing-out (all phases possibly achieved by the Early Quaternary). Periglacial reworking of the stone run material would have operated at a “final” stage, i.e. during Quaternary cold stages, with boulder bioweathering and limonite-staining operating during the temperate intervals including the present one. The suggested antiquity of the Falklands blockstreams is in accordance with Caine's pioneer interpretation of Tasmania blockfields and with recent analyses and cosmogenic datings of blockfields from Scandinavia and North America.