C. Sudha ¹, Ajesh K. Kottuppillil ², P. T. Ravichandran ¹, K. Divya Krishnan ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN
2 Department of Civil Engineering, SAINTGITS College of Engineering, Kottayam - 686532, Kerala, IN

Abstract

Background/Objectives: In the construction of structures river sand used as fine aggregate in concrete for centuries. River sand is not a renewable natural resource. In most of the area, river sand has been excessively exploited, which has endangered the stability of river banks and the safety of bridges, and creates an environmental problem. Hence, minimization of the use of river sand inevitable. Methods: In this study, the Manufactured sand (M-sand), produced by crushing rock depositions as a fine aggregate used in concrete. The M-sand is more angular and has rougher surface texture than river sand. In the M60 grade concrete, M-sand is used as fine aggregate and Bagasse Ash (BA) used as a pozzolanic material for the partial replacement of cement. Bagasse ash has partially replaced by the ratio of 0%, 10%, 20%, 30% and 40% by volume of cementation material in concrete. M-sand has been replaced by fully by volume of fine aggregate. In this investigation, to study the properties of concrete test likes Compressive Strength, Tensile Strength, Flexural Strength, Young’s modulus and Workability of concrete were carried out. The effects of M-sand on mechanical properties, studies with and without partial replacement of Bagasse ash were studies at the age of 7, 28 days. Findings: The test results show that the incorporation of Bagasse Ash up to 20% replacement level increases the mechanical properties of concrete. The variation in use of M-sand in concrete as compared to the river sand with the Bagasse Ash shows the minimum variation in the strength properties. Applications/Improvement: From this study, it is observed that the use of M-sand in high strength concrete can be use for the replacement of fine aggregate in M60 concrete. Use of Bagasse ash up to 20-30 % can be effectively used in concrete with or without the addition of M-sand, where the Bagasse ash available in plenty.

Keywords

Bagasse Ash, Compressive strength, Manufactured Sand.

Full Text

   

V. Umamaheswaran ¹, C. Sudha ¹, P. T. Ravichandran ², P. R. Kannan Rajkumar ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur – 603203, Tamil Nadu, IN
2 Department of Civil Engineering, SRM University, Kattankulathur – 603203, Tamil Nad, IN

Abstract

Due to rapid development in urban area, use of high strength concrete in the construction industry is increasing rapidly. Mineral admixtures such as Ground Granulated Blast furnace Slag (GGBS), Metakaolin, Silica fume and Alccofine are become unavoidable in high strength concrete because of their effects in hardened concrete properties. Replacing the Ordinary Portland Cement (OPC) by mineral admixtures is retaining the natural resources for future generation. In present scenario, replacement of river sand with manufactured sand is almost mandatory due to scarcity of the river sand. Superplasticizers are used to improve the workability of concrete at low water-cement ratio and increase the compressive strength by reducing it. In urban infrastructure development, the high strength concrete is mandatory to reduce the size of structural member, and to increase the utility space to carry heavier load. In this study M100 grade concrete mix was designed with replacement of OPC by different types of mineral admixtures using river sand and manufactured sand along with Polycarboxylate Ether (PCE) based superplasticizer. The Compressive strength, flexural strength and split tensile strength at various curing periods such as 28 and 56 days. The durability properties such as Rapid Chloride Penetration test, Water penetration test and water absorption test were carried out on the specimens at 28 and 56 days. Also, the Drying shrinkage of the concrete was tested at 14 days. From the experimental test results it is observed that, all the mixes were achieved the target mean strength, among these the Alccofine with Manufactured sand combination has achieved 21% higher than the target strength at age of 56 days and other strength parameters such as split tensile and flexural strength also slightly increased in this combination comparatively. The durability tests (Rapid chloride penetration, water penetration and drying shrinkage) were conducted and the obtained values at the age of 56 days are within permissible limit as per the codal provisions and the concrete with manufactured sand shows slightly higher value than concrete with river sand.

Keywords

Alccofine, Durability, High Performance Concrete, High Strength Concrete, M Sand, Metakaolin, Silica Fume

Full Text

   

Bobby A. Mathew ¹, C. Sudha ¹, P. R. Kannan Rajkumar ¹, P. T. Ravichandran ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur – 603203, Tamil Nadu, IN

Abstract

This paper focuses on the analytical and experimental investigations carried out on the tensile properties of High Strength Steel Fibre Reinforced Concrete (HS-SFRC). The steel fibres used here are circular double-end hooked steel fibres and the grade of concrete used is M60. The High Strength concrete is prepared using Silica Fume and Fly Ash as admixtures, along with a Super Plasticizer. The direct tensile tests have been carried out on specimens with different fibre combinations, viz., 0.5% and 1% as well as controlled concrete specimens. The analytical investigations were carried out using the Finite Element Analysis software ABAQUS (Version 6.10). The steel fibres were modelled using the geometry module before distributing and orienting them vertically based on the calculated fibre composition along critical failure zones identified within the concrete specimen. The plain concrete specimen was assigned a linear elastic property prior to analysis. Another model with a homogenous material property has also been generated and analysed for tensile loading. The results obtained from analysis were correlated using the experimental results.

Keywords

Fibre Volume Fraction, Heterogeneous Modelling, High Strength Steel Fibre Reinforced Concrete, Hooked Steel Fibres, Ultimate Tensile Strength

Full Text

   

C. Sudha ¹, K. Divya Krishnan ¹, P. T. Ravichandran ¹, P. R. Kannan Rajkumar ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur, Chennai - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: The construction industry mainly aims at sustainable construction with the available natural resources by reducing the negative environmental impacts on environment. Over a period of time, the scarcity of fine aggregate has become one of the most complex and challenging problem in the construction field. In India, the escalation in the price of natural river sand leads to the demand in the alternate construction material by considering Manufactured Sand (M sand) as a fine aggregate which solve the problem of scarcity. The focus of the present investigation is to assess the potential of using Manufactured sand as a replacement to fine aggregate in M60 grade concrete. Fly ash and silica fume also used to reduce the cement content and as a voids filler material. Methods Statistical Analysis: In the present investigation, it is aimed at to study 0, 25, 50, 75 and 100% of traditional fine aggregate replaced with M- sand. The test results are obtained by conducting compressive strength test, split tensile strength test and flexural strength test after 3, 14, 28 and 60 days of curing. Findings: The strength characteristics of concrete shows higher its strength with the partial and 100% replacement of M-sand in fine aggregate for all the curing period studied. An increase of 6.27% and 14.65 % in compressive and split tensile strength is observed by the full replacement of river sand with M- sand at the curing period of 28th day. Application/Improvements: Use of Manufactured sand in high strength concrete serves better alternative for the river sand. The utilization of manufactured sand in concrete as fine aggregate reduces the problem in scarcity of natural sand and reduces the time delay and cost of the construction.

Keywords

Compressive Strength, High Strength, Manufacatured Sand, River Sand.

Full Text

   

K. Divya Krishnan ¹, P. T. Ravichandran ¹, C. Sudha ¹, V. Janani ¹, Manisha Gunturi ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: Buildable land with good natural bearing capacity is reducing and it leads to the construction of buildings on poor soils which are finally leads to structural foundation failures. This necessitated the use of available admixtures for the improvement of soil characteristics economically. Among the available resources, industrial by- products can be effectively used as admixtures since it can solve the hazardous problems due to its disposal. Methods: Grain size analysis and Atterberg’s limits tests are conducted to classify the soils used in this study. To evaluate the effect of admixtures, strengths characteristics of soils were observed by Unconfined Compressive Strength and California Bearing Ratio tests. Weak soils having high expansive characteristics are used to study the activation of 5% fly ash blended with Phospho Gypsum (PG) at varying percentages of 2%, 4% and 6% with two weak soils at different curing conditions. Findings: Results shows higher strength development upto a percentage of 4% PG with 5% flyash with both the soils. Effect of curing periods on strength characteristics of treated soils at 7, 28 and 60 days were also considered in this study. Microstructural studies are also showing an improvement in microstructure which is examined in SEM micrographs and XRD results. The influence of flyash with different percentages of phosphogypsum on swelling characteristics shows a decrease in swell potential of treated soil with increase in curing periods. Improvement: This study gives an effective application of Phospho Gypsum and Fly Ash in geotechnical field by using it as a relevant soil stabilizer. Increase in CBR values were obtained with Fly Ash and Phospho Gypsum combinations with soils, which reduces the thickness of pavement and making more productive use of industrial wastes with considerable environmental benefits.

Keywords

Compressive Strength, Fly Ash, Phosphogypusm, Stabiisation

Full Text

   

P. T. Ravichandran ¹, K. Divya Krishnan ¹, Manisha Gunturi ¹, C. Sudha ¹, P. R. Kannan Rajkumar ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives: Problematic soils cause more damage to structures which are resting over it due to less strength to support the loads acting on them during the construction as well as in service periods. A proper treatment of the subgrade soil is required for providing a stable working area for the construction of structures. In geotechnical point of view, soil stabilization with suitable admixtures fulfils the improvement in the soil characteristics for construction of foundation for light structures and pavements. Methods/Statistical Analysis: In this study an attempt is made to analyse the effect of soil stabiliser RBI grade 81 on two different soils treated with varying percentages of admixture for different curing periods. The strength properties are studied by conducting the UCC and CBR test for treated soils with 2%, 4% and 6% of RBI for specific curing of 7, 28 and 60 days. Microstuctural studies by Scanning electron microscopy had done on untreated and treated soils shows the relevant structural changes which promotes the strength attainment with the addition of admixtures while curing period increases. Findings: This study shows a substantial improvement in problematic soils by treated with RBI grade 81 shows the increasing value of UCC ranging from 1.5 to 11 times and California Bearing Ratio values shows an increase of 65% and 41% from 2% and 2.19% for the both the soils with the addition of 6% RBI additives at the curing period of 60 days. Improvement/Applications: Use of RBI 81 in soil stabilisation renders a better stabilizing agent making the soils capable of meeting the constructional requirements with improved engineering properties.

Keywords

CBR, RBI 81, Soil Stabilisation, UCS

Full Text

   

K. Francis Yakobu ¹, P. T. Ravichandran ¹, C. Sudha ¹, P. R. Kannan Rajkumar ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203,Tamil Nadu, IN

Abstract

Limestone and clay which are the major ingredients of the cement production are non-renewable resources. Therefore, it is essential to identify a sustainable material to replace cement. The by-product from the steel plant is subsequently granulated to desired fineness and is termed as Ground Granulated Blast furnace Slag (GGBS). Superplasticizers (SP) are used to improve the workability of concrete at low water-cement ratios and increase the compressive strength by reducing it. But, this workability is sometimes lost rapidly as time progresses after contact between the cement and water. Therefore, it is necessary to understand the mechanisms that influence the cement-super plasticizer interaction for selecting an appropriate type of admixture at an optimum dosage. In this present research the compatibility study, between six combinations of cement using different percentages of GGBS with two different SPs were investigated. The optimum dosage was found using marsh cone test. The cement mortar flow test was conducted to find out the setting time and compressive strength of the mortar. It is found that the increase in addition of GGBS decreases the dosage of Superplasticizers to achieve the desired workability. The target mean strength of the M40 concrete was achieved with replacement of 50% GGBS using PCE based SP.

Keywords

GGBS, Saturation Dosage of SPs, Slump Retention

Full Text

   

P. R. Kannan Rajkumar ¹, K. Divya Krishnan ¹, C. Sudha ¹, P. T. Ravichandran ¹, T. D. Vigneshwaran ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN

Abstract

Background/Objectives:The present generation of fly ash in the country is about 90 million tonnes and quarry dust is about 65 million tonnes. The utilization of fly ash in cement and other related industries is less than 10%. Safe disposal of remaining fly-ash and quarry dust has become a challenging problem. It is therefore necessary to utilize fly-ash and quarry dust in structural elements. The most basic building material for construction of houses is the usual burnt clay brick. A significant quantity of fuel is utilized in making these bricks and the burning of these fossil fuels liberate green house gases which cause depletion of ozone layer. Also, continuous removal of topsoil, in producing conventional clay bricks, creates environmental problems. Methods/Statistical Analysis: A feasibility study was undertaken on Fly ash-Lime-Gypsum (FaL-G) bricks and Quarry dust-Fly ash-Lime-Gypsum (QuFaL-G) bricks to use as a building element. The bricks of size 220 x 100 x 75mm were casted to study the strength and durability characteristics. Results shows that the compressive strength of FaL-G bricks was 8.2 N/mm2 on the 28th day, which is much higher than the conventional burnt clay bricks (>3.5 N/mm2). Findings:The water absorption property of FaL-G brick is lesser than the water absorption of normal good quality burnt clay bricks (20%). Applications/Improvements: In view of the strength and durability characteristics of these bricks, it can be used in place where the fly ash and quarry dust available more in quantity to solve the consequences of pollution and at the same time to build houses economically by utilizing industrial wastes.

Keywords

Fly Ash, FaL-G Bricks, Gypsum, Lime, QuFaL-G Bricks

Full Text

   

C. Sudha ¹, P. T. Ravichandran ¹, K. Divya Krishnan ¹, P. R. Kannan Rajkumar ², A. Anand ¹

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu, IN
2 Department of Civil Engineering, SRM University, Kattankulathur - 603203, Tamil Nadu

Abstract

Background/Objectives: National Green Tribunal which has taken cognisance of this and has enforced severe restrictions on sand mining from river beds and relevant laws for obtaining licence have been made very stringent. Hence there is a need to look for alternatives to river sand without sacrificing performance of concrete / mortar. Methods/Statistical analysis:  In this work, experimentally investigate the effect of M-sand in concrete by replacing the river sand (0%, 25%, 50%, 75% and 100%) and develop a high performance high strength concrete with target strength of 40MPa. Findings: The investigations are carried out to study the effect of M-sand on mechanical properties of concrete such as Compression, Tensile and Flexural Strength at the age of 3, 7, 28 and 56 days. Result shows that, there is a liner increase in compressive strength with the replacement of 0 to 100% river sand by M-sand. Replacement of 100% of river sand by M-Sand induced higher compressive, split tensile and flexural strength at the end of 28 days. The increase in strength was in the order of 12-18% as compared to concrete with river sand. Similar results also showed an increase in the strength parameters at the longer duration of curing periods. Applications: Studies revealed that, the use of M-sand in concrete for the construction purpose is acceptable for the concrete of grade upto M40 and also reduce the exploitation of river sand

Keywords

Compressive Strength, Flexural Strength, Flyash, M-Sand, Split Tensile Strength

Full Text

   

K. Divya Krishnan ¹, Mani Deepika ¹, P. T. Ravichandran ¹, C. Sudha ¹, Ajesh K. Kottuppillil ²

Affiliations
1 Department of Civil Engineering, SRM University, Kattankulathur- 603203, Tamil Nadu, IN
2 Department of Civil Engineering, SAINTGITS College of Engineering, Kottayam - 686532, Kerala, IN

Abstract

Background/Objective: Civil engineering structure resting on expansive soils needs more attention since it causes undesirable engineering behavior when the soil comes in contact with water. The areas consisting of expansive soil need a proper stabilization method to solve the site problems faced by the civil engineers. Pavements constructed on such soil shows signs of damage continuously during the service life of the pavement eventually increase the maintenance costs. Stabilization of these soils is a usual practice for improving the strength. Methods: In this work an attempt was made on the utilization of Phospho Gypsum (PG) with soil by adding various percentages of 2, 4, and 6% in soils and accessed their geotechnical behaviour for different curing periods. The effects of PG treatment on the microstructure and strength improvement of compacted expansive clays are studied based on Microstuctural analysis and Unconfined Compression tests for different curing periods of 0, 14 and 28 days. Findings: UCS performed on these mixes and identified that addition of phosphogypsum attained high strength with the increasing percent of phosphogypsum in soils. From the test results, it was observed that the UCS peak stresses were increases to 162kPa and 336kPa from 75 kPa and 122 kPa for soil samples S1 and S2 at 28days of curing. X-ray Diffraction and Scanning Electron Microscopy were carried out for microlevel analysis and the results confirmed the presence of minerals and cementation nature in the treated soil. Improvement: From the experimental study, it is observed that the treatment of the expansive soil with the addition of Industrial waste material Phosphogypsum is more efficient in subgrade modification and other geotechnical applications.

Keywords

Compaction, Phosphogypsum, Stabiliser, UCS

Full Text