Roller-compacted concrete (RCC) is an accepted and economical method for the construction of dams and pavements. Achieving adequate compaction is essential to the development of the desired properties in the hardened material. The compaction depends on many variables, including the strength of the subbase, materials used in RCC, mixture design proportions, mixing and transporting methods, discharge and spreading practices, compaction equipment and procedures, and lift thickness. The best performance characteristics are obtained when the concrete is reasonably free of segregation; well-bonded at construction joints; and compacted at, or close to, maximum density.
This report summarizes experience in compaction of RCC in various applications and offers guidance in the selection of equipment and procedures for compaction, as well as for quality control of the work. Compaction equipment and procedures should be appropriate for the work. In dam or massive concrete applications, large, self-propelled, smooth, steel-drum vibratory rollers are most commonly used. The frequency and amplitude of the roller should be suited to the mixture and lift thickness required for the work. Other roller parameters, such as static mass, number of drums, diameter, ratio of frame and drum mass, speed, and drum drive influence the rate and effectiveness of the compaction equipment. Smaller equipment, and possibly thinner compacted lifts, are required for areas where access is limited.
Pavements are generally placed with paving machines that produce a smooth surface and some initial compacted density. Final density is obtained with vibratory rollers. Rubber-tired rollers can also be used where surface tearing and cracks would occur from steel-drum rolling. The rubber-tired rollers close fissures and tighten the surface.
Inspection during placement and compaction is also essential to ensure the concrete is free of segregation before compaction and receives adequate coverage by the compaction equipment. Testing is then performed on the compacted concrete on a regular basis to confirm that satisfactory density is consistently achieved. Corrective action should be taken whenever unsatisfactory results are obtained. Roller-compacted concrete offers a rapid and economical method of construction where compaction practices and equipment are a major consideration in both design and construction.
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ACI CODE-355.2 prescribes testing programs and evaluation requirements for post-installed mechanical anchors intended for use in structural applications addressed by ACI 318 and subjected to static or seismic loads in tension, shear, or combined tension and shear. Criteria are prescribed for determining whether anchors are acceptable for use in uncracked concrete only, or in cracked as well as uncracked concrete. Performance categories for anchors are established, as are the criteria for assigning anchors to each category. The anchor performance categories are used by ACI 318 to assign capacity reduction factors and other design parameters.
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AASHTO T 85, 2022 Edition, 2022 - Standard Method of Test for Specific Gravity and Absorption of Coarse Aggregate
This method covers the determination of specific gravity and absorption of coarse aggregate. The specific gravity may be expressed as bulk specific gravity, bulk specific gravity (saturated surface-dry (SSD)), or apparent specific gravity. The bulk specific gravity (SSD) and absorption are based on aggregate after 15–19 h of soaking in water. This method is not intended to be used with lightweight aggregates.
The values stated in SI units are to be regarded as the standard.
This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this procedure to consult and establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to its use.
The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.
Code:
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AASHTO T 84, 2022 Edition, 2022 - Standard Method of Test for Specific Gravity and Absorption of Fine Aggregate
This method covers the determination of bulk and apparent specific gravity, 23/23°C (73.4/73.4°F), and absorption of fine aggregate.
This method determines (after 15–19 h of soaking in water) the bulk specific gravity and the apparent specific gravity, the bulk specific gravity on the basis of mass of saturated surface-dry (SSD) aggregate, and the absorption.
The values stated in SI units are to be regarded as the standard.
This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this procedure to consult and establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to its use.
The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.
Code:
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Greetings all.
I need a reference (in English) for construction methods in Iraq (in the past and present), especially in Kadhimiya. Please let me know if there exists such a reference.
I really appreciate any help you can provide.
Proceedings of the 1st Conference of the European Association on Quality Control of Bridges and Structures
Author(s): Carlo Pellegrino, Flora Faleschini, Mariano Angelo Zanini, José C. Matos, Joan R. Casas, Alfred Strauss Edition: 1st Publish Date: 2021 ISBN: 978-3-030-91877-4 Published By: Springer Related Links:
Code:
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Protection of Historical Constructions: Proceedings of PROHITECH 2021
Author(s): Ioannis Vayas, Federico M. Mazzolani Edition: 1st Publish Date: 2022 ISBN: 978-3-030-90787-7 Published By: Springer Related Links:
Code:
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can someone plese share a download link for this paper:
Particle breakage behavior of a foundation filling material on island-reefs in the South China Sea under impact loading
Author(s): Wang, X., Cui, J., Shen, JH. et al.
Publish Date: 2022 Published By: Springer Related Links:
Code:
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