Conclusions

We have presented preliminary results on the modification of cement pastes by two types of nanostructures nanosilica and carbon nanotubes. The impact of these nanostructures in the compressive strength is analysed. Two types of nanosilica have been used colloidal suspension and agglomerated dry silica. We have observed that colloidal silica behaves much better than the agglomerated silica, since with lower weight of silica better results are obtained. This is due to the fact that colloidal...

Extended Abstract

How can we convey, something of Nanotechnology and its relevance to society and to industries and to people There's so much to think about. I can only start to prompt, from a personal perspective and that is essentially all that I will try to do. Over the coming days, months and years, more discussion and exchange should help all of us to think widely and freely. It is easy to get dazzled by the glitz and the headlines of Nanotechnology. By images Nanobots and nanomachines that self-assemble....

Nanotechnology In Construction

Construction was among the earliest of industrial sectors in identifying nanotechnology as a promising emerging technology, e.g. in the UK Delphi survey of the early 1990s,16 and in foresight reports of Swedish and UK construction.1 18 Two sectors of the construction industry, namely ready mixed concrete and concrete products, were also identified as among the top 40 industrial sectors likely to be influenced by nanotechnology within 10-15 years. However, the application of nanotechnology in...

Contents

Nanotechnology and Construction in the 21st Century From nanotechnology to new production systems the EU perspective. 3 Nanotechnology in civil engineering. 13 Nanotechnology business and investment opportunities. 23 Integration of european nanotechnology research in construction. 25 Application of nanotechnology in construction - current status and future 31 W. Zhu, J. C. Gibbs and P. J.M. Bartos Nanotechnology for construction beyond the imagery. 47 Focused Ion Beams (fib) - tools for serial...

Nanosilica

In the concrete industry silica is a well-known agent that plays an important role as both binding and filling agent in the development of HPC. The usual product is the so-called silica fume or microsilica18 with diameters ranging from 0,1 nm to 1 pm and a content of silica usually above 90 by weight. In this way, microsilica is in the limit of nanometer sized materials that are added to cement to increase performance of cementitious composites. Nanosilica is just nanometric size silica (S1O2)....

Swnt

TEM image of MWNT employed in this work Results for the compressive strength at 28 days of cement pastes with the different types of nanosilica presented in Table 1 are plotted in Fig. 3 as a function of the grams of admixture. This coincides with the by weight of cement, since we have always used 100 gr. of cement as stated in the previous section. Therefore, 0 grams corresponds to plain cement paste. Each value represents the average over twelve measurements, and the bars represent the...

From Nanoscale To Macroscale

Cement based materials, such as hydrated cement pastes, mortars, plain and fibre reinforced concretes are widely used in the construction of modem structures. During their service life, depending on the environmental conditions they are in, many structures are exposed to various types of aggressive agents. Intrusion of the aggressive agents into the cement based materials, which directly affects durability, is generally controlled by the diffusivity and permeability of the material. In...

Fak

Among geopolymer samples the best performance in both tests had the samples activated by sodium hydroxide with the weight loss in acetic and sulphuric acid solutions respectively 0.45 and 1.96 . Next in performance were samples activated by sodium silicate solution, which had 3.83 weight gain in acetic acid solution, and 2.56 weight loss in sulphuric acid solution. The performance of the samples prepared with sodium hydroxide and potassium hydroxide solutions was good in acetic acid solution...

Info

0 2 4 6 8 10 12 14 Figure 3 Compressive strength at 28 days of nanosilica modified cement pastes In the case of colloidal silica the results are even more pronounced. This can be understood taking into account that in this case the nanosilica is purely nano, i. e., it is not agglomerated due to the stabilisation of the medium in which is dispersed. Levasil Grade 100 (white triangles), which is stabilised by a solution of 0,23 Na20 in water, shows a remarkable increase with respect to Nyacol...

Introduction

The Greek philosopher Democritus (465-370), who is often considered as one of the precursors of modern chemistry, assumed that attempts to understand the basic properties of matter would finally lead us to adoption of inseparable entities. He called these entities atoms. At that time he did speculate about the size of those atoms. His assumptions show, however, that throughout the centuries people have been looking for a reference from which on they could explain phenomena observed in the real...

Xrd

Figure 4 presents XRD traces of the samples prepared with sodium silicate and sodium hydroxide solutions. It was found that the main phases formed in the samples are amorphous, and only in case of materials prepared with sodium hydroxide solution semi-crystalline zeolitic phases were present after 1 month of storage. The zeolitic products formed depended on the curing regime. In materials with 2 hours precuring at room temperature and exposed to elevated temperature curing at 75 C as in Case I...