the purpose of the present study was to synthesize and characterize nanosilica from alkali-extraction of silica fume under controlled conditions using poly (vinyl alcohol) (pva) as a dispersing agent. the dissolution efficiency of silica fume was affected by various factors such as concentration of the reagent, reaction time and temperature. a maximum dissolution efficiency of 91% was achieved ...

Despite its few inherent shortcomings, concrete has proved to be the most widely used construction material, no substitute in time still to come. In the present investigation, study of admixture of concrete was carried out. The strength of concrete depends on its mix proportions. We used so many admixture e.g. ‘silica. Fumes, fly ash etc , when we used these type of admixture the result was ver...

Nanosilicas have been known as super-pozzolanic materials and compared to silica fume, these materials have higher purity of silica and finer particles. However, in contrast to silica fume, nanosilicas are produced by various methods, leading to different morphologies and agglomeration statuses in their initial form. On the other hand, due to several mechanisms such as the bridging effect of ca...

recent tendencies in concrete technology have been towards to high- performance concrete with a low water-cement ratio. however, high performance concretes have some problems. one of the problems is early-age cracking due to autogenous shrinkage. this study presents the results of an experimental investigation carried out to evaluate the autogenous shrinkage of high-strength concrete. accordin...

This paper presents the results of an experimental investigation carried out to evaluate the shrinkage of High Strength Concrete. High Strength Concrete is made by partially replacement of cement by flyash and silica fume. The shrinkage of High Strength Concrete has been studied using the different types of coarse and fine aggregates i.e. Sandstone and Granite of 12.5 mm size and Yamuna and Bad...

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...

The results of experimental investigations on the study of concrete with partial replacement of cement are presented in this paper. The concrete grade of M30 has been selected and designed as per Indian Standard method. The specimens based on control mix have been cast without fly ash and silica fume. Cement was replaced by 0%, 10%, 20%, 30%, 40%, 50% and 60% of fly ash by the weight. 20 % of s...

The current paper proposes skew Gaussian mixture models for speaker recognition and an associated algorithm for its training from experimental data. Speaker identification experiments were conducted, in which speakers were modeled using the familiar Gaussian mixture models (GMM), and the new skewGMM. Each model type was evaluated using two sets of feature vectors, the mel-frequency cepstral coe...