Precast prestreesed concrete braces are a new method for seismic strength of Concrete Structures which has the following benefits: a) no wet concrete work in construction site b) No bolt or anchorage to the existing frame c) easy to apply d) short construction period e) low construction cost, to evaluate seismic performance of strengthened structure a model consist of existing frame and concret...

There have been great developments in the area of civil engineering in the recent few decades and among these, construction and material innovation are quite prominent. Steel-concrete composite construction has emerged as one of the fastest methods of construction. Even though considerable research efforts on conventional reinforced concrete columns have been executed prior to now, concrete fil...

For more than 100 years, the primary theme underlying the NBS/NIST staff contribution to the crystallography of building materials has been the development of an improved understanding of concrete materials performance. Over that time period, portland cement concrete has become one of the most important of our construction materials for roads, buildings, and other large municipal structures. At...

We analyze the concrete security of a hash-based signature scheme described in the most recent Internet Draft by McGrew, Fluhrer and Curcio. We perform this analysis in the random-oracle model, where the Merkle-Damgård hash compression function is models as the random oracle. We show that, even with a large number of different keys the attacker can choose from, and a huge computational budget, ...

research on the heavy concrete technology expanded rapidly in the last decades. this kind of the concrete can be used for different purposes such as the protective shields of the medical centers and nuclear power plants. ilmenite, limonite, hematite, magnetite and barite are the common mineral aggregates which are used in the heavy concrete construction technology. in this research the mechanic...

Grout is a binding agent or binder often used with building materials to improve their durability functions. It may be organic or inorganic material used for sealing or consolidation of cracks, pores, or voids in order to improve the mechanical properties and impermeability of a particular system, whether soil, cementitious or of other building materials. Grouts act as dispersion agents where d...

concrete is one of the most widely used materials in construction industry. many large and important structures such as power plants, bridges, dams and buildings employ concrete as main material. propagation of crack is considered one of the main reasons in failure of concrete structures. the process of formation and crack growth is one of the major and complex issues in concrete, because concr...

in the construction process of a plastic concrete cut-off wall, concreting is usually performed using the termie pipe method. in this method, concreting is performed from the lowest point in the excavated trench (containing the slurry) using a funnel and the pipe connected to it. the concrete poured in the funnel gradually settles in the panel through the termie pipe which is beneath the slurry...

Nanotechnology will serve as a suitable solution to achieve high performance in future construction and construction. Using this new technology, creativity and innovation can be achieved in the building industry. one of these new technologies of smart concrete is that in recent years, many researches and experiments have been done in scientific research centers around the world, so that the con...

this paper describes a methodology in designing high-performance concrete for simply supported beams, using a hybrid optimization strategy based on a variable neighborhood search threshold acceptance algorithm. three strategies have been applied to discrete optimization of reinforced concrete beams: variable neighborhood descent (vnd), reduced neighborhood search (rns) and basic variable neighb...