Effect of Addition of Combination of Admixtures on the Properties of Self Compacting Concrete Subjected to Sulphate Attack

Vol.2 No. 4

Year: 2012
 
Issue: Sep-Nov

Title: Effect of Addition of Combination of Admixtures on the Properties of Self Compacting Concrete Subjected to Sulphate Attack

Author Name: Shanthappa. B. C., Prahallada M.C , Prakash K.B

Synopsis: 

This paper presents an experimental investigation on the effect of acid attack  on the properties of SCC produced by the combination of admixtures such as (Superplasticizer + Viscosity modifying admixture + Air entraining agent + Accelerator), (Superplasticizer + Viscosity modifying admixture + Air entraining agent + Retarder), (Superplasticizer + Viscosity modifying admixture + Air entraining agent + Water proofing compound ) and (Superlasticizer + Viscosity modifying admixture + Air entraining agent + Shrinkage reducing admixture). The concrete testing specimens was prepared by a mix proportion 1:2.7:6.1:5.1 with cement: fly ash: sand: coarse aggregate with a water/binder ratio of 0.38. Specimens after 28 days of curing were immersed in sodium sulphate solution of 5% and 10% concentrations for 90 days. After 90 days of immersion, the specimens were removed from sulphate media, weighed accurately and tested for their respective strengths. SCC produced with above combination of admixtures show better resistance to sulphate attack as compared to SCC produced with combination of admixtures (SP+VMA) only.

Effect Of Elevated Temperatures On The Properties Of Steel Fiber- Reinforced Self-Compacting Concrete

Vol.2 No. 4

Year: 2012

Issue: Sep-Nov

Title: Effect Of Elevated Temperatures On The Properties Of Steel Fiber- Reinforced Self-Compacting Concrete

Author Name: M.S. Shreenivas Reddy, P. Srinivasa Rao

Synopsis:

Mechanical and thermal properties of steel fiber-reinforced self- compacting concrete(SFR-SCC) subjected to elevated temperatures up to 600oC were experimentally investigated and reported in this paper. The variables considered in this study include grade of concrete (M35, M45, M55 and M65), fiber content (0, 0.5 and 1%), elevated temperatures (200oC, 400oC and 600oC) and period of exposure to the above temperatures (4hrs, 8hrs and 12hrs). Specimens were placed in an electric furnace and the heating was applied at the rate of five degree per minute until the desired temperature was reached. Specimens were then allowed to cool in the furnace and tested for loss in mass and compressive strength. Similar tests were also performed at room temperatures for the reference specimens. The experimental results show that the mass loss and strength loss does not exceed 10 and 50% respectively and also in case of fibreless specimens micro cracks were observed at 600oC.

Strengthening of RC Two-way Plates using Ferrocement

Vol.2 No. 4

Year: 2012

Issue: Sep-Nov

Title: Strengthening of RC Two-way Plates using Ferrocement

Author Name: S.P.Singh, Hardeep Singh Rai , Harpreet Gaba

Synopsis:

A structure consists of the load carrying members which transfer the superimposed load to the foundations below. Its proper function must be served during its life. But the deterioration starts with some passage of time in case of RC structures. Various factors are responsible for this i.e environmental factors, loads, fire, and earthquake and so on.  The concept of structure health monitoring and strengthening of structures is a major step towards well being of any structural system and its intended performance under various loads. Ferrocement have been widely used in various forms as structural element. In the present paper, feasibility of using ferrocement is assessed for strengthening of a deteriorated RC two way slab. Rebound hammer and ultrasonic pulse velocity tests were conduced to assess the degree of deterioration. Results were presented in the form of load-deflection response of the slabs along with crack pattern of the slab at various stage of loading. Results are found to be in well agreement with those obtained from analytical investigations.

Effect Of Replacement Of Natural Sand By Stone Crusher Dust On The Properties Of Waste Plastic Fibre Reinforced Concrete - An Experimental Investigation

Vol.2 No. 4

Year: 2012

Issue: Sep-Nov

Title: Effect Of Replacement Of Natural Sand By Stone Crusher Dust On The Properties Of Waste Plastic Fibre Reinforced Concrete - An Experimental Investigation

 

Author Name: Prahallada M.C, Prakash K.B 

Synopsis:

The waste plastic is causing a serious environmental pollution. The plastic don’t deteriorate. It is a non-biodegradable material. Once the plastic takes the birth, it is not subjected to any deteriorating actions. With all these things it is causing a serious environmental pollution. Such waste plastic fibres can be used in the concrete to produce waste plastic fibre reinforced concrete. Aim of this paper is to present the properties of waste plastic fibre reinforced concrete when natural sand is replaced by crushed stone sand by different percentages. The strength characteristics of waste plastic fibre reinforced concrete like compressive strength, tensile strength, flexural strength and impact strength are found along with workability characteristics when natural sand is replaced by crushed stone sand by different percentages like 0%, 10%, 20%, 30%, 40%, 50% and 60%. It can be concluded that 30% replacement of natural sand by stone crusher dust in waste plastic fibre reinforced concrete yield maximum strength and yields good workability characteristics. Thus, waste plastics and stone crusher dust which are causing environmental pollution can be effectively used in concrete.

Earthquake-induced vibrations of a buried pipeline including fluid-structure interaction – numerical solution

Vol.2 No. 4

Year: 2012

Issue: Sep-Nov

Title: Earthquake-induced vibrations of a buried pipeline including fluid-structure interaction – numerical solution

Author Name: Silviya Petkova, Dimitar Kisliakov

Synopsis:

In the present work, the governing equation of the dynamic response of a buried fluid-conveying pressure pipeline to a transverse earthquake excitation is solved numerically. The structural model of the buried pipe corresponds to the type implemented in hydropower systems. An Euler-Bernoulli beam on elastic Winkler foundation is applied in the transverse vibration model of the buried pipe with appropriate boundary conditions. The constant velocity flow of the inviscid fluid in the pipe is approximated as a plug flow. The Finite Difference Method (FDM) in the form of a fully implicit scheme is applied for the solution of the governing equation of motion. Since this differential equation is of fourth order, two additional mathematical functions are introduced for enabling such numerical treatment. Making use of the implicit FDM with appropriate boundary and initial conditions, the problem converts to a system of algebraic equations with block-tridiagonal structure for each time step within the solution mesh whose right-hand side depends on the results from the previous time step and the earthquake-induced kinematic excitation. The time and space shift of the input seismic excitation over all points of the FD mesh is calculated by means of a special external procedure. For practical application of this computational procedure, a computer program SIVBuPP was written in the MATLAB environment. The numerical algorithm was tested independently by means of a small example and external calculation tools. Further, a numerical example with real structural data and displacement and velocity records from the Duzce 1999 earthquake was solved as implementation of the developed procedure. Finally, conclusions were drawn, and some tasks for future research were formulated as well.