Manufactured sand differs from natural sea and river dredged sand in its physical and mineralogical properties. These can be both beneficial and detrimental to the fresh and hardened properties of concrete. This paper presents the results of a laboratory study in which manufactured sand produced in an industry sized crushing plant was characterised with respect to its physical and mineralogical...

Concrete Vibration can take some time ans sometimes it just seems to take longer than it should to pour and consolidate a precast product, such as concrete pipe or a manhole section. Frustrated by sluggish procedures, The Cretex Companies’ Rapid City, South Dakota, plant determined to improve on the half hour it took to pour zeroslump concrete, consolidate it, and get the top ring in place on t...

The results of an environmental study on concrete manufacture that follows the standard protocol of life cycle assessment are shown in this document. The study has been done for seven types of concrete: one conventional and six containing cement kiln dust (10%), marble sludge (10%) and demolition waste (10%, 80% and 100%) respectively, in partial or total substitution of natural aggregate. Six ...

As for all materials, the performance of concrete is determined by its microstructure. Its microstructure is determined by its composition, its curing conditions, and also by the mixing method and mixer conditions used to process the concrete. This paper gives an overview of the various types of mixing methods and concrete mixers commercially available used by the concrete industry. There are t...

Materials issues are a key concern for the existing nuclear reactor fleet in the United States as material degradation can lead to increased maintenance, increased downtime, and increased risk. Extending reactor life to 60 years and beyond will likely increase susceptibility and severity of both known and new forms of degradation. A multitude of concrete-based structures are typically part of a...

the present work has been performed to eliminate sewage dry sludge of alborze city wastewater treatment plant by using them as fine aggregate in concrete. on this basis, at first the selected dry sludge was analyzed for xrd and xrf for crystalline phases and chemical composition, respectively. the results showed that more than 50% of the sludge is formed of sio2 and it had more than 20% organic...

having observed the costly failures of different cutoff walls, that had been constructed according to the mix design specified by reputable consultants in iran, a research programme was conducted to study the effects of constituent materials on the properties of plastic concrete. the main properties, such as compressive strength, biaxial and triaxial strains, permeability, and modulus of elasti...

This paper explains concepts underlying a just-in-time production system. Just-in-time production systems as implemented by Toyota are pull systems in which ‘kanban’ convey the need to replenish the right inventory at the right time and in the right amount. In this paper, symbols from manufacturing are introduced to map resource flows in order to help distinguish traditionalfrom lean production...

Hemp concrete is more and more recommended by eco-builders because hemp is a renewable plant, recyclable and does not degrade within time. To integrate this material into buildings, it is important to study its hygrothermal behaviour. In this paper, two models have been investigated: a heat transfer model (Th) and a hygrothermal model accounting for heat and moisture transport through building ...