Effect of Replacement of Cement by Metakalion on the Properties of High Performance Concrete Subjected to Acid Attack

Vol.2 No. 3

Year: 2012

Issue: Jun-Aug

Title: Effect of Replacement of Cement by Metakalion on the Properties of High Performance Concrete Subjected to Acid Attack 

Author Name: Beulah M., Prahallada M.C 

Synopsis: 

This paper presents an experimental investigation on the effect of partial replacement of cement by metakalion by various percentages viz 0%, 10%, 20%, and 30% on the properties of high performance concrete, when it is subjected to acid attack. An aggregate binder ratio of 2 and different water binder ratios viz 0.3, 0.35, 0.40 and 0.45 was used in this investigation. Concrete specimens of size 150 x 150 x 150 mm were casted to find residual compressive strength and specimens of size 100 x 100 x 100mm were casted to find percentage weight loss; both the sizes of specimens were casted and cured as per IS specification. After 28 days water curing, the concrete specimens were kept immersed in 5% concentrated acid solution for 30, 60 and 90 days for observation. Before immersion, they were weighed accurately and after required days of immersion and observation, the specimens were removed from acid media, weighed accurately and tested for their compressive strength; weight loss and hardness of concrete were studied. The various results which indicate the effect of replacement of cement by metakalion on HPC are presented in this paper to draw useful conclusions. The results were compared with reference mix. Test results indicate that use of replacement cement by metakalion in HPC has improved performance of concrete up to 10%

Durability of Steel Fibre Reinforced High Strength Metakaolin Blended Concrete

Vol.2 No. 3

Year: 2012

Issue: Jun-Aug

Title: Durability of Steel Fibre Reinforced High Strength Metakaolin Blended Concrete 

Author Name: P. Srinivasa Rao, Abdul Rahim.Z , Seshadri Sekhar Tirumala 

Synopsis: 

Cement Concrete is most widely used material for various constructions. When compared with steel, concrete is most widely used in construction. But concrete has some of the drawbacks like low tensile strength, less ductility, heavy weight, high shrinkage and high permeability. To overcome these drawbacks many researchers all over the world are actively involved in improving the properties of the concrete according to their applications. As a part of my research work an attempt is made to study the strength & durability of steel fibre reinforced Metakaolin blended concrete, when it is exposed to certain types of chemicals. Metakaolin is a thermally structured, ultra fine pozzolona, which replaces industrial byproducts such as silica fume,  fly ash, etc.,. This paper presents experimental investigations carried out to evaluate the strength and the durability in terms of Chemical Resistance and weight loss of steel fibre reinforced concrete with and without Metakaolin for concrete of M50 grade. Concrete cubes are made with partial replacement of ordinary Portland cement by Metakaolin. Water to cementitious material ratio used is 0.55. The optimized dosage of super plasticizer is noticed as 1 % weight of binding material. In this investigation an attempt is made with chemicals like H2SO4 and HCl. Crimped Steel fibres with 80 as aspect ratio at 0, 0.5%, 1.0% and 1.5% of volume of concrete are used. The results show that the percentage of weight loss is reduced and compressive strength is increased in the case of Steel fibre reinforced concrete and concrete containing 10 % Metakaolin replaced concrete when compared to the normal concrete. Also the less percentage weight loss is noticed in the case of HCl and severe in the case of H2SO4.

Studies on High Strength Self Compacting Concrete Mixes Using Mineral Admixtures

Vol.2 No. 3

Year: 2012

Issue: Jun-Aug

Title: Studies on High Strength Self Compacting Concrete Mixes Using Mineral Admixtures 

Author Name: Seshadri Sekhar Tirumala, S. Sesha Phani , P. Srinivasa Rao , P. Sravana 

Synopsis: 

In the present investigation a rational mix design is established and self compactability testing methods have been carried out from the view point of making it a standard concrete by using   mineral admixtures like micro silica and fly ash for imparting High Strength Self Compacting Concrete. The  flow properties of resulting concrete is characterized in the fresh state by methods used for Self compacting concrete, such as Slump-flow, V-funnel and L- box tests respectively. Further the mechanical properties compressive strength, split tensile strength and flexural strength of concrete are examined for High Strength Self Compacting Concrete mix of grade M100.

Impact Strength Of Steel Fibre Reinforced High Strength Self Compacting Concrete

Vol.2 No. 3

Year: 2012

Issue: Jun-Aug

Title: Impact Strength Of Steel Fibre Reinforced High Strength Self Compacting Concrete 

Author Name: Vasusmitha Joshi, P. Srinivasa Rao 

Synopsis: 

Cement based materials are quasi-brittle and are known to exhibit a highly stress-rate sensitive behavior. In structures that are subjected to impact forces, this causes concern in two ways: first the brittleness may result in catastrophic failure without warning and second, the properties of concrete during such events may be very different from those measured in standardized quasi static tests. Unfortunately, there are no standardized tests available for testing concrete under impact loading and there is significant confusion as to what constitutes an appropriate test. Concrete is a mostly used construction material in the world. As the use of concrete becomes wide spread the specifications of concrete like Durability, Quality, Compactness and Optimization of concrete becomes more important. Self Compacting Concrete (SCC) is a very fluid concrete and a homogeneous mixture that solves most of the problems related to ordinary concrete. Besides, SCC gets compacted under its own weight and there is no need for an internal vibrator for the body of the mould. This specification helps the execution of construction components under high compression of reinforcement. This paper concentrates mainly on studying the properties like workability and Impact strength of Fibre Reinforced High Strength Self Compacting concrete using Steel Fibres in various proportions ranging from 0 to 1.5 % for SCC mixes of Grade M 80.The resulting concrete is characterized in the fresh state by methods used for Self compacted concrete, such as Slump flow, V-funnel and L-Box tests respectively.

Studying The Effect Of Maintaining The Urban Roads At Different Serviceability Levels And Applying Deferred Maintenance

Vol.2 No. 3

Year: 2012

Issue: Jun-Aug

Title: Studying The Effect Of Maintaining The Urban Roads At Different Serviceability Levels And Applying Deferred Maintenance 

Author Name: Yogesh Shah, S.S. Jain , Tiwari, Devesh , Jain M.K 

Synopsis : 

The level of service defines the appropriate level of maintenance and the priority placed on the work. These levels can be used in planning, performing and evaluating the various maintenance activities with available funds. According to Indian codes, the priorities for levels of service are set for three possible levels of maintenance funding viz. (i) desirable level (highest level of funding) (ii) average level (iii) acceptable level (lowest level of funding). The main objective of a pavement maintenance management system is to provide a scientific tool to maintain roads at desired serviceability levels. It is also well accepted fact that due to paucity of funds it is not possible to provide the highest level of serviceability and hence there’s a need to evaluate the pavement conditions at lower serviceability levels. This case study demonstrates the determination of fund requirements for maintaining the urban pavement sections as per three serviceability levels defined as desirable, average and accepted. The analysis has done using HDM-4 shows the effect of changing the serviceability level on varying fund requirements and the pavement network condition. Also, the effect of applying the deferred maintenance to the urban pavement sections due to scarcity of funds is analyzed. The 23.7 Km road length of Noida urban city, near Delhi is selected for this study.

Practical Way To Identify The False Target Signatures In Gpr Images Of Ground Profile

Vol. 2 No. 2

Year: 2012

Issue: Mar-May

Title: Practical Way To Identify The False Target Signatures In Gpr Images Of Ground Profile 

Author Name: D.C. Bala, S.S. Jain 

Synopsis: 

The application of ground penetrating radar (GPR) for pavement evaluation is relatively new concept in India, especially for transportation infrastructure study to evaluate its defects and condition rapidly, continuously and non-destructively. The images of the studied pavement section containing underground utility (here metallic water pipes & electric cables are taken) items show hyperbolic signatures and by using velocity calibration by hyperbolic matching approach it is possible to determine the depth and leakage status. But, generally the main problem that is encountered in the analysis of the GPR image is the occurrence of false hyperbolic signatures which may appear due to the reflection from nearby big trees, houses and overhead bridges/ under ways.  It is therefore, important to resolve the issue of detection of false target in air by GPR. Thus, in the present work practical data have been acquired using 250 MHz ground coupled GPR from the areas having big objects that can interfere with the GPR images. The GPR signatures of the trees, fly over and overhead pathway have been collected, and based on the GPR acquired velocity (from GPR image) of the electromagnetic (EM) wave propagating through the ground has been analyzed to differentiate between the air objects and the ground objects. After analysis it has been found that if the GPR extracted velocity is within the range of (0.050 m/ns to 0.150 m/ns), it represents all sorts of ground materials (generally used for construction) under various moisture conditions (presence of huge water to dry condition), and the object is under the earth surface. Whereas, if the velocity is above 0.19 m/ns or 0.200 m/ns and above represents false air events i.e. object is in air. This work can provide technical assistance to the beginners involved in the GPR based manpower development programmes.

 

 

 

Experimental Studies On Ferrocement Slabs Using Self Compacting Mortar

Vol. 2 No. 2

Year: 2012

Issue: Mar-May

Title: Experimental Studies On Ferrocement Slabs Using Self Compacting Mortar 

Author Name: Deepa Shri, R. Thenmozhi 

Synopsis: 

Now-a-days ferrocement elements are used as building material as well as structural materials, since ferrocement can put the building into diet. Ferrocement elements are thin, flexible and the steel reinforcement is distributed widely throughout the cement mortar. Instead of cement mortar, self compacting mortar is used in order to eliminate the external vibration and to overcome the difficulties and problems in the construction process and it can flow through congested formwork and corners where the conventional cement mortar cannot facilitate perfect filling and compaction. The objective of this study was to develop the properties of self compacting mortar using SCC principles. 3 mixes of SCM were prepared by maintaining constant percentage of Super Plasticizer and Viscosity Modifying Agent of 0.85% and 0.23% respectively and varying w/c in the range of 0.40, 0.45 and 0.50 with mortar ratio of 1:2. For each mixes 9 cubes (7cm X 7cm X 7cm) were cast. The workability of the fresh mortar determined using slump flow and V-funnel tests. The hardened properties were determined at 3, 7, 28 days of age. The SCM test results were compared with the control specimen to see the inference of self-compatibility. This mortar developed is applied in the construction of the ferrocement slabs and their behaviour was studied.