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Testing Concrete Cores

By
KAUSHAL KISHORE
Materials Engineer, Roorkee

The examination and compression testing of cores cut from hardened concrete is a well – established method, enabling visual inspection of the interior regions of a member to be coupled with strength estimation. Other properties which can be measured is also given in this paper.

IS: 456-2000 specified that the points from which cores are to be taken and the number of cores required shall be at the discretin of the engineer-in-charge and shall be representative of the whole of concrete concerned in no case, however, shall fewer than three cores be tested. Core shall be prepared and tested as described in IS: 516.

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Advance Construction Material – Micro Silica In Concrete

By
Prof. Balasaheb E.Gite,Prof. Madhuri K. Rathi, Prof.Rajesh S.Rajguru, Prof. Asif P.Shaikh
Amrutvahini College of Engineering, Sangamner
University of Pune.

Abstract:
Micro silica is an amorphous type of silica dust mostly collected in bag house filters as by-product of the silicon and ferro-silicon production. The paper summarizes important physical and chemical properties of micro silica and uses those results for an evaluation of micro silica from a Health Safety and Environment (HSE) standpoint. Micro silica consists of spherical particles with an average particle size of 150 nm and a specific surface area of typically 20 m3/g. The chemical and physical properties of this inorganic product are different as compared to other amorphous and crystalline silica poly morphs. More than 500.000 MT of micro silica are sold to the building industry world-wide and are used in fibre cement, concrete, oil-well drilling, refractories, and even in polymers.

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Study Of The Strength Geopolymer Concrete With Alkaline Solution Of Varying Molarity

By
M.ADAMS JOE (Associate Professor, Dept. of Civil Engineering, TREC, Nagercoil, Tamilnadu,India.)
A.MARIA RAJESH (Assistant Professor, Dept. of Civil Engineering, ACEW, Nagercoil, Tamilnadu,India.)
ROY MAMMEN (Director of Quality Assurance, Dept. Of Built Environment Engineering, Muscat College,Oman.)

ABSTRACT
Manufacture of Portland cement produces large of volumes of carbon dioxide and other gases. Releasing these gases causes atmospheric pollution and subsequent environmental degradation. Finding a suitable alternative solution to mitigate the environmental degradation caused by using Portland cement is very important for environmental sustainability. The use of geopolymer concrete as an alternative material over Portland cement concrete to reduce the adverse effects on the environment is investigated in this paper. The paper also critically analyses the economic and environmental benefits of geopolymer concrete and address the financial and environmental issues associated with the production and use of Portland cement. Geopolymer cement utilizes industrial waste materials such as fly ash from thermal power stations to provide a practical solution to waste management as well as environmental protection methods.

Geopolymer concrete products are known to possess far better durability and strength properties than Portland cement concrete. These properties are investigated extensively in laboratory to verify and confirm the superior durability and strength properties. The paper also discusses the factors which restrict the use of geopolymer concrete as an alternative to Portland cement concrete. Laboratory tests are conducted on compressive strength, split tensile strength and flexural tests for specimens with combination of different molarity. The results obtained are compared analytically and graphically

Keywords—GPC, Low calcium flyash, GGBS, steel fibres, Alkaline liquid, compressive strength, split tensile strength and flexural Strength
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Concrete Mix Design – ITS Acceptance

By
KAUSHAL KISHORE
Materials Engineer, Roorkee

Concrete mix design is the process of choosing suitable ingredient of concrete and determining their relative quantities with the object of producing as economically as possible concrete of certain minimum properties, notable workability, strength and durability. It should be explained that an exact determination of mix proportions by means of table or computer data is generally not possible. The materials used are essentially variable and many of their properties cannot be assessed truly quantitatively. A Laboratory trial mix does not provide the final answer even when the moisture condition of aggregates are taken into account. Only a mix made and used on the site can guarantee that all properties of the concrete are satisfactory in every detail for the particular job in hand. In fact mix selection requires a knowledge of the properties of concrete and experimental data, and above all the experience of the expert who conduct the mix design. The selection of mix proportions is an art as much as a science. It is not enough to select a suitable concrete mix; it is also necessary to ensure a proper execution of all the operation involved in concreting. It cannot be stated too strongly that, competently used, concrete is a very successful construction material but, in the literal service of the word, concrete is not fool proof. The mix proportions once chosen, cannot expected to remain entirely immutable because the properties of the ingredients (cement, sand, aggregate, water and admixture) may vary from time to time.
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Concrete Mix Design with Fly Ash and Superplasticizer

By
KAUSHAL KISHORE
Materials Engineer, Roorkee

Fly ash or pulverished fuel ash (pfa) is a finely divided powder thrown out as a waste material at the thermal power plants using pulverized coal for raising steam in the boilers. In the building industry, the use of fly ash a part replacement of cement in mortar and concrete at the construction site has been made all over the world including India and is well known. The important building materials which can be produced from fly ash are:

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