Influence of nano-SiO 2 on properties of fresh and hardened high performance concrete: A state-of-the-art review

2017 ◽  
Vol 148 ◽  
pp. 648-658 ◽  
Author(s):  
Peng Zhang ◽  
Jinyi Wan ◽  
Kejin Wang ◽  
Qingfu Li
Author(s):  
Jean-Michel Bosgiraud ◽  
Maurice Guariso ◽  
Franc¸ois Pineau

The research and development work presented in this paper was initialized by Andra in 2007. The work necessary for manufacturing and testing a full scale demonstrator is presently implemented. The case story is twofold. The first part is related to the initial development of a high performance concrete formulation used for fabricating concrete storage containers (containing Intermediate Level and Long Lived Waste primary canisters) to be stacked and emplaced into 400-m long concrete lined horizontal disposal vaults (also called cavern), excavated in the Callovo-Oxfordian clay host formation at a 550 to 600-m depth, with an inside diameter of approximately 8-m. The fabrication of the concrete boxes is illustrated. The second part presents the outcome at the end of the detailed design phase, for a system which is now being manufactured (for further test and assembly), for the emplacement of the concrete containers inside the vault. The application was engineered for remote emplacing a pile of 2 concrete containers (the containers are preliminarily stacked in a pile of 2, inside a hot cell, thanks to a ground travelling gantry crane). The emplacement process is justified and the related emplacement synoptic is illustrated. The test campaign is scheduled in 2011–2012. The successful completion of the technical trials is mandatory to confirm the mechanical feasibility of remotely emplacing concrete containers into large horizontal disposal caverns over long distances. The later display of the machinery at work in Andra’s showroom will be instrumental for the confidence building process involving the various stakeholders concerned by the public enquiry period (mid-2013) preceding the deep geological repository license application (2014–2015).


2017 ◽  
Vol 3 (3) ◽  
pp. 190-198 ◽  
Author(s):  
Mohamadtaqi Baqersad ◽  
Ehsan Amir Sayyafi ◽  
Hamid Mortazavi Bak

During the past decades, there has been an extensive attention in using Ultra-High Performance Concrete (UHPC) in the buildings and infrastructures construction. Due to that, defining comprehensive mechanical properties of UHPC required to design structural members is worthwhile. The main difference of UHPC with the conventional concrete is the very high strength of UHPC, resulting designing elements with less weight and smaller sizes.  However, there have been no globally accepted UHPC properties to be implemented in the designing process. Therefore, in the current study, the UHPC mechanical properties such as compressive and tensile strength, modulus of elasticity and development length for designing purposes are provided based on the reviewed literature. According to that, the best-recommended properties of UHPC that can be used in designing of UHPC members are summarized. Finally, different topics for future works and researches on UHPC’s mechanical properties are suggested.


2017 ◽  
Vol 2 ◽  
pp. 45-52 ◽  
Author(s):  
Pierre Pimienta ◽  
Maria Cruz Alonso ◽  
Robert Jansson McNamee ◽  
Jean-Christophe Mindeguia

High-performance concrete (HPC) is one of the most recent types of concrete among the materials used routinely in building and civil structures. Their development in structures applications and the growing need for the justification of their fire resistance has led several laboratories to carry out research on their properties at high temperature. This letter presents some main aspects related to their physicochemical changes, thermal properties and mechanical properties at high temperature. It introduces a State of The Art prepared by the RILEM Technical Committee 227-HPB (Physical properties and behaviour of High-Performance Concrete at high temperature) and untitled “Behaviour of High-Performance Concrete at high temperatures”. This State of the Art will be publish in a next future.


1997 ◽  
Vol 30 (S1) ◽  
pp. 47-53
Author(s):  
Raymundo Rivera-Villarreal ◽  
Süheyl Akman ◽  
Shigeyoshi Nagataki ◽  
Richard Gagné

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