Search or add a thesis

Advanced Search (Beta)
Home > Properties of High Performance Concrete With Supplementary Cementitious Materials

Properties of High Performance Concrete With Supplementary Cementitious Materials

Thesis Info

Access Option

External Link

Author

Elahi, Ayub

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2009

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1054

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727038584

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


The aim of this research was to evaluate the performance of high performance concretes (HPC) containing supplementary cementitious materials in both binary and ternary systems. Concretes were prepared to have a slump between 60-90 mm at a constant water-binder ratio of 0.30. The test variables included the type and the amount of supplementary cementitious materials (SCMs) such as silica fume (SF), class F fly ash (FA) and ground granulated blast-furnace slag (GGBS). Portland cement was replaced with FA up to 40%, silica fume up to 15% and GGBS up to a level of 70%. The physical properties were assessed from the compressive strength and transport properties (air permeability and sorptivity), whilst the durability characteristics were investigated in terms of carbonation, chloride diffusion, chloride migration, electrical resistivity and salt- scaling resistance. The hydration properties of cement pastes containing SCMs have also been investigated in order to understand the behaviour of HPC. For the hydration properties, cement pastes were prepared in two series (A and B). Mixes of series A had a fixed water-binder ratio of 0.30 with superplasticiser, whereas the water-binder ratios of mixes in series B were equivalent to the standard consistencies. The results confirmed that silica fume performed better than other SCMs for the strength development and bulk resistivity. In terms of the resistivity of concrete, the best performance was obtained for 15% SF concrete. When 7.5% SF was used in 40% FA and 50% GGBS concrete, the resistivity was less than that of the 15% SF concrete. However, in both cases, this was greater than the control concrete. The ternary mixes containing GGBS/FA and SF performed the best amongst all the mixes to resist the chloride diffusion. The mix containing FA showed favourable permeation results. All the ternary combinations can be considered to have resulted in high performance concretes with excellent durability properties. The maximum carbonation depth observed for concrete containing 40% FA and 7.5% SF was about 5 mm, which is less than the cover of reinforcing steel bars to cause corrosion. The non-steady state migration coefficients of concretes containing different types of ivSCMs were significantly lower than that of the control concrete. The coefficient was minimum for concrete containing 15% SF. The scaled mass for 40% FA concrete was the maximum among all the mixes. For concrete containing GGBS, there was no significant change in the scaled mass, when compared to the control concrete. However, the use of 15% SF was found to reduce the scaled mass. The use of 7.5% SF in 40% FA and 50% GGBS concrete was found to reduce the scaled mass. The X-ray diffraction (XRD) data showed that with the addition of high volumes of FA, GGBS and SF the peak intensity of Ca(OH) 2 was retarded and quartz peaks appeared in paste containing FA denoting a certain amount of crystalline silica in FA. This was more pronounced at later age. The combination of 40% FA and 7.5% SF showed the highest consumption of Ca(OH) 2 . Thermo-gravimetry (TG) data confirms that the addition of SCMs in cement resulted in the formation of decreased amount of Ca(OH) 2 in the hydration products considerably at later age when compared to the early age. Although the addition of high volumes of SCMs decreased the compressive strength of cement pastes particularly at the early age, the use of 15% SF improved the strength. However, from the cost point of view, t is suggested that a combination of 40% FA and 7.5% SF or 50% GGBS and 7.5% SF can be beneficially used to improve the hydration properties and compressive strength of cement paste.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

احسان دانش

احسان دانش
قلم یہاں تک پہنچا تھا کہ ایک اخبار میں اچانک اپنے عزیز اوردیرینہ دوست احسان دانش کے انتقال کی خبر نظر سے گزری توصدمہ ہوا۔ مرحوم ضلع مظفر نگر کے ایک قصبہ میں پیداہوئے، لاہور پہنچ کرمزدوری کی،اسی سے مزدوروں کے شاعربنے۔ بڑی شہرت اورمقبولیت پائی، تقسیم کے بعد مرجھا سے گئے تاہم اطمینان اورفارغ البالی کی زندگی بسر کرتے تھے۔ طبعاً مرنج ومرنجان،متواضع و منکسر المزاج اورعقیدہ وعمل کے اعتبار سے پکے مسلمان تھے۔
اللھم اغفرلہ وارحمہ۔
[اپریل۱۹۸۲ء]

 

Exploring the Success Factor Of Digital Marketing: A case study of Private Healthcare Organization in an Emerging Economy

Abstract The purpose of this study is to assess the potential of social media platforms to build a successful marketing campaign for the private health-care industry. This will be accomplished by studying the current trends, audiences, and marketing tactics that are applied to these channels. In addition, the research will make a contribution to this understanding by investigating the efficacy of various types of marketing strategies that are used in the private health-care industry, such as influencer marketing, content marketing, and social media advertising, and how these strategies can be leveraged to create marketing strategies that are more effective. This research project will also focus on identifying any bottlenecks that could be hindering the utilisation of these channels and providing solutions to improve their effectiveness in the marketing mix. This will be done as part of the overall goal of improving the effectiveness of the marketing mix. At the end of the day, the purpose of this research is to develop an understanding of how social media channels can be utilised successfully as an important instrument in marketing for the health-care industry.

Synthesis, Electrical Properties and Bio-Compatibility Analysis of Barium Manganate Nanostructures

Single phase barium manganate nanorods, nanoparticles, nanofibers and microparticles were prepared using composite–hydroxide mediated (CHM) method, hydrothermal (HT) technique, electrospinning (ES) and solid state reaction (SSR) route respectively. Size and uniformity of BaMnO 3 nanorods were optimized against different reaction times and reaction temperatures. BaMnO 3 powders consisting of nanorods of an average diameter ~ 200 nm and length ~1 – 1.5 μm, prepared at reaction temperature 200 °C and reaction time 48 hours, were chosen for electrical characterization. Impedance spectroscopy (IS) from 300 – 400 K and 20 Hz – 2 MHz, revealed presence of non-ideal Debye type behaviour in BaMnO 3 samples and was attributed to the presence of heterogeneity in the sample. The heterogeneity was explained on the basis of “brick layer model”. In BaMnO 3 nanorods sample, on the basis of extracted capacitance values, two electro-active regions were investigated i.e., dominant grain boundaries and sample-electrode interfaces. No indication from the bulk effect was observed. Experimental results were fitted using equivalent circuit model (R gb Q gb )( R e Q e ). The ac and dc conduction mechanisms in BaMnO 3 pellets can be explained by correlated barrier hopping (CBH) model and Poole– Frenkel conduction mechanism respectively. While IS analysis of bulk BaMnO 3 sample revealed that different electro-active regions such as grain, grain boundary and sample- electrode interface exist that overlapped with each other in the applied frequency domain. These results were also modelled via a best fit equivalent circuit model (R g C g )(R gb Q gb )(R e Q e ) and the response from different overlapped electro-active regions were separated. The ac conductivity obeys CBH model for bulk BaMnO 3 sample. Uptake of PEGylated BaMnO 3 NPs alone and loaded with photosensitizer (5-ALA) were examined on Hep2c cell lines. It was observed that PEGylated BaMnO 3 NPs loaded with 5-ALA has higher uptake as compared to 5-ALA. The high uptake was attributed to large surface area of BaMnO 3 NPs. It was also observed that BaMnO 3 NPs are non-toxic when administrated to Hep2c cell lines. BaMnO 3 nanofibers were synthesized for the first time using ES technique. Effect of different polyvinyl pyrrolidone (PVP) concentration on uniformity and homogeneity of nanofibers was investigated.