Introduction: The present study aimed to evaluate the impact of PbO nano and micro-sized fillers on ordinary and heavy concretes for different photon energies. Material and Methods: The MCNPX Monte Carlo code (version 2.6.0) was used for all simulations in the present study. A model of narrow-beam geometry was validated and utilized to calcul...

One research field in Leipzig deals with the design of high strength lightweight-aggregate concretes (HSLWAC). Due to the huge waveband of this concretes with all possible combinations of lightweight-aggregates and mortar matrix the formulation of general rules is difficult. Therefore both components lightweight-aggregates and mortar matrix will be investigated in detail in order to achieve a d...

The core catcher is arranged in an unattended, unventilated sub-reactor space. It designed to receive molten corium emergencies, and thus the concrete used must be resistant high temperatures without significant loss of strength. During nuclear power plant (NPP) operation, these concretes are subjected considerable radiation exposure, which may also affect their physical–chemical properties. Co...

As regards if curing stops for some time and then resumes again, then strength gain will also stop and reactive, in this study with choose suitable curing conditions after improper first curing (recurring) for normal and silica-fume concrete, Effect of this curing conditions on strength and permeability was investigated. The results from tests such as compressive strength, capillary water absor...

concrete has a special place at the current century; it has been and is the most widely used building material. producing concrete has several environmental impacts that should be considered to prevent consequent problems. in recent years, several methods have been developed to produce concrete that is compatible with the environment and sustainable development basis. in these concretes, beside...

DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclose...

In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite, sometimes blended with unr...

Bio-concretes are receiving special attention in recent research as an alternative for climate change mitigation due to their low carbon footprints. Different bio-based materials can be used, e.g., wood shavings, bamboo, rice husk, and coconut. However, various methodological parameters influence the footprint of materials, especially bio-concretes, like biogenic carbon, amount dry matter, rota...

Currently, in civil engineering, high performance concrete i.e. concretes whose minimum compression strength is equal or more than 65 MPa are increasingly used. Side effect of it is need for determination of their construction strength. In particular, recently built high performance structures suffer from sampling of drill cores. Therefore, noninvasive impact hammers – to be specific Schmitt im...

Concrete rheological properties need to be properly measured and predicted in order to characterize the workability of fresh concrete, including special concretes such as self-consolidating concrete (SCC). It was shown by a round-robin test held in 2000 [1,2] that different rheometer designs gave different values of viscosity for the same concrete. While empirical correlation between different ...