Concrete Engineering

Submitted by :BILAL RIAZ CHUGHTAI.
Group members:BILAL RIAZ CHUGHTAI, MUDASSAR MEHMOOD GHUMMAN, MUHAMMAD SOHAIL SALEH and AOON MUHAMMAD HANIF.
Supervised by: Dr. ATTAULLAH SHAH.

INTRODUCTION
1.1 GENERAL
In the world of construction, concrete like other materials is playing an important role in development. concrete is a composite material which is a mixture of cement, fine aggregate , coarse aggregate and water .The major constituents of which is natural aggregate such as gravel, sand, Alternatively, artificial aggregates such manufactured sand furnace slag, fly ash, expanded clay, broken bricks and steel may be used where appropriate. It possesses many advantages including low cost, general availability of raw material, adaptability, low energy requirement and utilization under different environmental conditions.

The goal of sustainable construction is to reduce the environmental impact of a constructed facility over its lifetime. Concrete is the main material used in construction in the world. Due to increase in Construction and Demolition activities worldwide, the waste concrete after the destruction of any infrastructure is not used for any purpose which is totally loss in the economy of the country because natural resource are depleting day by day. The debris is also a major problem for municipal authorities to dispose of at particular location. It is most common practice in all over the world that most of the materials (paper, plastic, rubber, wood, concrete, etc) are being recycled to save the natural resources and environment. Concrete is such a costly material but Now a day’s waste concrete is only being used as a landfill material instead of recycling the concrete as a recycled concrete aggregate (RCA) to use for the construction purposes.

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ABSTRACT
plain concrete possess very low tensile strength, limited ductility and little resistance to cracking .Internal micro cracks are inherently present in concrete and its poor tensile strength is due to propagation of such micro cracks. Fibres when added in certain percentage in the concrete improve the strain properties well as crack resistance, ductility, as flexure strength and toughness. Mainly the studies and research in fiber reinforced concrete has been devoted to steel fibers. In recent times, glass fibres have also become available, which are free from corrosion problem associated with steel fibres. The present paper outlines the experimental investigation conducts on the use of glass fibres with structural concrete. CEM-FILL anti crack, high dispersion, alkali resistance glass fibre of diameter 14 micron, having an aspect ratio 857 was employed in percentages , varying from 0.33 to1 percentage by weight in concrete and the properties of this FRC (fibre reinforced concrete) like compressive strength, flexure strength, toughness, modulus of elasticity were studied.
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By
Prof. B. E. Gite, Mr. Yogesh S. Nagare
Amrutvahini College of Engineering, Sangamner

Abstract
“Continuously reinforced concrete pavement” as the title suggests this type of pavement is reinforced throughout in longitudinal direction. This type of pavement has no transverse joints unless and until there is end of pavement or the pavement comes in contact with some other pavement or bridge. A longitudinal joint exists only if the road is wider than 14 feet. Due to reduction of joints smooth and continuous riding is possible resulting in fuel saving. Also CRCP roads are maintenance free if properly constructed and care is taken while placement of steel. Once CRCP roads are constructed they need not to be taken care of for the next 50-60 years. The principal behind this roads is that “Let the road crack”, exactly opposite as in case of other type of roads where we avoid crack formation at any cost. CRCP is allowed to crack due to which stresses in the pavement are released. The cracks formed are held tightly by the reinforcement, due to which widening and deepening of cracks is restricted. Hence we can conclude that in CRCP controlled cracking is permitted. The initial cost of CRCP is high, but as it is maintenance free, and lasts for decades, overall cost of CRCP is less as compared to other type of reinforced concrete pavements. Study and observations have shown that this type of roads are alarmingly successful, hence CRCP is widely used in USA, GERMANY, BRITAN, and several other developed and developing nations. Use of CRCP will enhance the cement, and steel industries; it will reduce the fuel consumption by vehicles, and will save lots of money required for frequent construction and repairs of other type of pavements.
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By
Kaushal Kishore
Materials Engineer, Roorkee

INTRODUCTION:
For the last 20 years, the use of by products of various origins in the production of concrete has become an increasingly widespread practice in the world. The main advantages are all the elimination of scraps and a reduction in the over exploitation of quarries.

Blast furnace slag is used in blended cement. Although many studies have been conducted on the evaluation of the electric arc furnace slag to be use in concrete as aggregates replacing natural aggregates, no studies have been performed regarding the use of induction furnace slag in concrete as aggregates replacing natural aggregates.

In making mild steel ingot scrap to sponge iron is fed into the induction furnace which produces large quantity of slag. For example Kotdwar a small town of Uttarakhand Steel Mills induction furnances alone generates 15,000 tonnes of slag per year and about 1,50,000 tonnes of slag is lying as dump around this city posing an environmental problem. If about 20 steel factories of Kotdwar generate such quantity of slag it can be calculated how much slag is being generated by about 600 induction furnace units of India.
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By
Kaushal Kishore, Materials Engineer, Roorkee

ABSTRACT:
The stresses induced in concrete pavements are mainly flexural. Therefore flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. A simple method of concrete mix design based on flexural strength for normal weight concrete mixes is described in the paper.

INTRODUCTION:
Usual criterion for the strength of concrete in the building industry is the compressive strength, which is considered as a measure of quality concrete. However, in pavement constructions, such as highway and airport runway, the flexural strength of concrete is considered more important, as the stresses induced in concrete pavements are mainly flexural. Therefore, flexural strength is more often specified than compressive strength in the design of concrete mixes for pavement construction. It is not perfectly reliable to predict flexural strength from compressive strength. Further, various codes of the world specified that the paving concrete mixes should preferably be designed in the laboratory and controlled in the field on the basis of its flexural strength. Therefore, there is a need to design concrete mixes based on flexural strength.
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For the design of staircase, there are three main scenarios:

(i) Stairs spans longitudinally
This kind of stairs refers to stairs spanning between landings only without any side supports. In this case, the staircase should be designed as a beam between two end supports (i.e. landing) and the main reinforcement is provided at the bottom of staircase slabs.

(ii) Stairs spanning transversely
This kind of staircase is supported by sidewalls only and it may also be supported by stringer beams. For the case of sidewalls, it acts as a cantilever beam and the main reinforcement are provided the top surface of slab. For the case of staircase supported sideways by both sidewall and stringer beam, it should be designed transversely with end supports as sidewall and stringer beam and reinforcement is provided at the bottom of the staircase.

(iii) Stairs resting on solid support
For stairs resting on solid supports, only nominal steel reinforcement is provided to control thermal and shrinkage cracking.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.

Submitted By
Vinayak Ravindra Supekar.
(National Institute Of Construction Management And Research Center, (Nicmar))

ABSTRACT:
Now days the construction industry in the India is facing one of the major problem that is natural fine aggregate. And court awarded that totally band on excavation of fine aggregate from river because they affect on environment and changing the river direction. (fig.5). Thus the more natural fine aggregate are highly needed to replace with artificial fine aggregate. This paper presentation the study of crack pattern of concrete slab, each size is (500*300*50) mm and replacement of natural fine aggregate with artificial fine aggregate by 20%,40% 60% 100% and also finding the compressive Strength of that concrete cube. And these experiment is carried out maintain temperature 32 0cAnd the according to experimental result show that the replacement of natural sand by artificial sand up to 60% and gives best result that is maximum strength and minimum area of crack.

Key words: – Concrete slab, natural fine aggregate, artificial fine aggregate (grit), crack pattern.
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By
Nagesh Tatoba Suryawanshi
Asst.Professor in Civil Engg. dept
S. B. Patil, College of Engineering, Indapur,(Pune).

Abstract

This Paper reports an experimental study carried out to investigate the use of water-soluble polyvinyl alcohol as self-curing agent. In this study Compressive and tensile strength of self-curing concrete for 7 and 28 days is found out and compared with conventional concrete of similar mix design. The durability of self curing concrete is found out by exposing concrete cubes to chloride environment and effect of the same on strength of cubes is determined by finding out compressive strength of cubes. The results indicated that Water retention for the concrete mixes incorporating self-curing agent is higher compared to conventional concrete mixes, as found by the weight loss with time. The result also showed that compressive, tensile and flexural strength of self curing concrete is found to be higher than conventional concrete.

Key words: Self curing agent, polyvinyl acetate, polyvinyl alcohol, water Retentivity. etc.

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By
Amir Juma
(Amir Juma is in his final semester of Bachelor of Science in Civil Engineering in Koneru Lakshmaiah University-India. His research interests lie in the field of Self Compaction Concrete.)

E.Rama Sai
(E.Rama Sai is in his final semester of Bachelor of Science in Civil Engineering in Koneru Lakshmaiah University-India. His research interests lie in the field of Self Compaction Concrete.)

D.V.A.K.Prakash
(D.V.A.K.Prakash is in his final semester of Bachelor of Science in Civil Engineering in Koneru Lakshmaiah University-India. His research interests lie in the field of Self Compaction Concrete.)

Md. Shahbaz Haider
(Md.Shahbaz Haider is in his final semester of Bachelor of Science in Civil Engineering in Koneru Lakshmaiah University-India. His research interests lie in the field of Self Compaction Concrete.)

S.Kanakambara Rao
(Associate Professor in Department of Civil Engineering in Koneru Lakshmaiah University-India. He specialized in structural Engineering and research interests lie in the field of Self Compaction Concrete.)

Abstract
Self-compacting concrete, also referred to as self-consolidating concrete, is able to flow and consolidate under its own weight and is de-aerated almost completely while flowing in the formwork. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC particularly useful wherever placing is difficult, such as in heavily-reinforced concrete members or in complicated work forms.

The objectives of this research were to make a synergic effect of Rice husk Ash (RHA) and Sugar cane bagasse ash(SCBA) incorporated in self compaction concrete in order to increase in strength and a better bonding between aggregate and cement paste, . The mix design used for making the concrete specimens was based on previous research work from literature. The water – cement ratios varied from 0.3 to 0.75 while the rest of the components were kept the same, except the chemical admixtures, which were adjusted for obtaining the self-compactability of the concrete.

All SCC mixtures exhibited greater vaules in compressive strength after being tested, the compressive strength was around 40% greater. In addition, the SCC had a good rheological properties as per the requirements from European standards from economical point of view the pozzolanic replacements were cheap and sustainable.
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By
Kaushal Kishore, Materials Engineer, Roorkee

Foamed concrete, also called cellular light weight concrete is produced by the mixing of Portland cement, sand including or alone fly ash, water and preformed stable foam. The foam is produced with the help of a foam generator by using foaming agent. The air content is typically between 40 to 80 percent of the total volume. The bubbles vary in size from around 0.1 to 1.5 mm in diameter. Foamed concrete differentiates from (a) gas or aerated concrete, where the bubbles are chemically formed through the reaction of aluminium powder with calcium hydro oxide and other alkalies released by cement hydration and (b) air entrained concrete, which has a much lower volume of entrained air is used in concrete for durability. Curing of foamed concrete unit may be done as per IS: 456-2000. Curing can be speeded up by steam.
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