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Evaluation of the rheological behavior of fresh self-compacting rubberized concrete by using the Herschel–Bulkley and modified Bingham models

Güneyisi E., Gesoglu M., Naji N., Ipek S.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 1

9--19

EN

The study herein presents the use of the Herschel–Bulkley and modified Bingham models to monitor the rheological behavior related to workability of the fresh self-compacting concrete containing waste rubber. Therefore, the self-compacting rubberized concretes were produced at a constant water-to-binder ratio of 0.35 and binder content of 520 kg/m3. Class F fly ash was incorporated as 30% of total binder content by weight. Two types of waste scrap tire rubber, crumb rubber and tire chips, were utilized instead of natural fine and coarse aggregate at various level, respectively. The tire chips and three different graded crumb rubbers (No.18, No.5, and mixed crumb rubber) and five designated rubber contents of 5%, 10%, 15%, 20%, and 25% were considered as experimental parameters. The rheological behavior related to workability of the fresh concretes was investigated by using the ICAR rheometer. The torque–speed relationship obtained from rheometer was used to characterize the rheological behavior of fresh self-compacting rubberized concrete by applying the Herschel–Bulkley and modified Bingham models to experimental data. The results revealed that the self-compacting concretes produced in this study exhibited shear thickening behavior and increasing the rubber content resulted in higher exponent ‘n’ values for the Herschel–Bulkley and c/μ coefficients for the modified Bingham models.

2

Sedimentological and micropalaeontological evidence to elucidate post-evaporitic carbonate palaeoenvironments of the Saudi Arabian latest Jurassic

Hughes G., Naji N.

Volumina Jurassica

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2008

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Vol. 6, no. 1

61-73

EN

The Hith Formation forms the youngest lithostratigraphic unit of the Jurassic Shaqra Group. It represents the culmination of a succession of hypersaline and euryhaline cycles that characterise the Late Jurassic of Saudi Arabia. The Formation is poorly exposed in central Saudi Arabia, but it has been studied in detail in subsurface eastern Saudi Arabia where the upper carbonate member hosts an important hydrocarbon reservoir called the Manifa Reservoir. Chronostratigraphic control is absent from the formation itself, and the Tithonian age is suggested for the Hith Formation based on its stratigraphic position between the underlying Arab Formation of Late Kimmeridgian age, and the overlying Sulaiy Formation, of Late Tithonian to Berriasian age. The Hith Formation needs redefining in the light of new lithological evidence, and a tripartite member scheme is suggested. This includes the lower anhydrite-dominated member here termed the “anhydrite” member, and considered to represent hypersaline subaqueous deposition within a restricted deep lagoon during the lowstand systems tract of the Manifa sequence. A “transitional“ member consists of interbedded anhydrites and carbonates and approximates with the transgressive zone. The overlying “carbonate” member represents the results of a prograding shallow, normal salinity marine succession related to the highstand systems tract. Interbedded carbonates within the evaporites are interpreted to represent superimposition of a higher frequency, possibly 4th order eustatic cyclicity. The “carbonate“ member hosts the Manifa Reservoir, and here proposed as the Manifa Member, consist of five parasequences, each of which represents a shoaling-upwards cycle with a succession of up to five repeated lithofacies and biofacies that commences with a stromatolitic, microfaunally-barren unit followed by fine-grained grainstones with a monospecific but abundant ostracod biofacies. A succession of coarse pelloidal grainstones with rare foraminifera, including Redmondoides lugeoni, Trocholina alpina with a variety of unidifferentiated valvulinids and miliolids then follows, that passes vertically into coarse ooid grainstones, with rare Redmondoides lugeoni, forming the uppermost part of each parasequence.

3

Post-evaporitic carbonates of the Saudi Arabian Late Jurassic

Hughes G., Naji N., Al-Khaled M., Harland T., Bacchus D.

Volumina Jurassica

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2006

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Vol. 4, no. 1

91-91

EN

The Hith Formation forms the latest lithostratigraphic unit of the Jurassic Shaqra Group, and was deposited during the Tithonian. The Formation outcrops in central Saudi Arabia, but has been studied in detail in subsurface eastern Saudi Arabia where the upper carbonate member hosts an important hydrocarbon reservoir called the Manifa reservoir. Chronostratigraphic control is absent, and the Tithonian age is based on stratigraphic position between the underlying Kimmeridgian Arab Formation, and the overlying Sulaiy Formation, of Berriasian age. The lower anhydrite-dominated member is un-named, and considered to represent subaqueous deposition representing the transgressive systems tract of the Manifa sequence. A transitional unit, consisting of interbedded anhydrites and carbonates, approximates with the maximum flooding zone, and the overlying carbonates are considered to represent the results of a prograding shallow marine succession related to the highstand systems tract. The carbonates of the Manifa reservoir consist of five parasequences, each of which represents a shoaling-upwards cycle that commences with a stromatolitic, microfaunally-barren unit that is followed by fine-grained grainstones with a monospecific but abundant ostracod biofacies. A succession of coarse pelloidal grainstones with rare Foraminifera, including Redmondoides lugeoni, Trocholina alpina and miliolids, then follows, that passes vertically into coarse ooid grainstones that form the uppermost part of each parasequence. The Hith Formation represents the culmination of a succession of hypersaline and euryhaline cycles that characterise the Late Jurassic of Saudi Arabia, and provides an insight to the palaeoenvironmental conditions that existed across the Arabian Plate at the end of the Jurassic.