Concrete Engineering

The main objective of asphalt mix design is to achieve a mix with economical blending of aggregates with asphalt to achieve the following :

(i) workability to facilitate easy placement of bituminous materials without experiencing segregation;
(ii) sufficient stability so that under traffic loads the pavement will not undergo distortion and displacement;
(iii) durability by having sufficient asphalt;
(iv) sufficient air voids

In asphalt mix design, high durability is usually obtained at the expense of low stability. Hence, a balance has to be stricken between the durability and stability requirements.

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.

By
MS. SNEHAL R. METKAR
(P.G. STUDENT)
DEPARTMENT OF CIVIL ENGINEERING
(STRUCTURAL ENGINEERING IIND YEAR)
P.R.M.T OF TECH. & RESEARCH, BADNERA-AMRAVATI
SANT. GADGE BABA (AMARAVATI) UNIVERSITY (MAHARASHTRA)
COUNTRY INDIA – 444701

GUIDED BY
Prof A. R. Mundhada
(PROFESSOR)
DEPARTMENT OF CIVIL ENGINEERING,
P.R M.I.T.R., BADNERA, AMRAVATI.
MAHARASHTRA, INDIA-4444701,

Abstract
Water tanks are used to store water and are designed as crack free structures, to eliminate any leakage. In this paper design of two types of circular water tank resting on ground is presented. Both reinforced concrete (RC) and prestressed concrete (PSC) alternatives are considered in the design and are compared considering the total cost of the tank. These water tank are subjected to the same type of capacity and dimensions. As an objective function with the properties of tank that are tank capacity, width &length etc.

A computer program has been developed for solving numerical examples using the Indian std. Indian Standard Code 456-2000, IS-3370-I,II,III,IV & IS 1343-1980. The paper gives idea for safe design with minimum cost of the tank and give the designer the relationship curve between design variable thus design of tank can be more economical ,reliable and simple. The paper helps in understanding the design philosophy for the safe and economical design of water tank.

Keywords
Rigid based water tank, RCC water tank, Prestressed Concrete, design, details, minimum total cost, tank capacity
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Presented By
Er.T.RANGARAJAN, B.E, M.Sc(struct.engg), F.I.E, FACCE, LACI, LISSE, LIASE

WHO IS AN ENGINEER?
According to USA President Herbert Hoover, who was an engineer before he became a politician, said:
The great liability of the engineer …compared to men of other professions……is that his works are out in the open where all can see them.
His acts …..step by step …are in hard substances.
He cannot bury his mistakes in the grave like the DOCTORS.
He cannot argue them into thin air…..or blame the judge…..like the LAWYERS.
He cannot, like the ARCHITECT, cover his figures with trees and vines.
He cannot, like the politicians, screen his shortcomings by blaming his opponents….and hope the people will forget. The ENGINEER simply cannot deny he did it.
If his works do not work……he is damned.

Important Points from Presentation
A design engineer’s responsibility should include assuring the structural safety of the design, details, checking shop drawing.
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Let’s take an example to illustrate the sequence of closing and opening of joints (Ministry of Transport (1955)). For instance, an unreinforced concrete carriageway is constructed in winter. When temperature rises in the following summer, the section between expansion joints will expand as a whole single element resulting in the closure of expansion joints. This section of concrete pavement will move outwards from the mid-point
between the expansion joints. In the next winter, each bay (i.e. concrete pavement between adjacent contraction joints) of concrete contracts about the midpoint of its length with opening of contraction joints.

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.

Research Paper by
A.Dhasarathan^1, Dr. R. Thenmozhi², Mrs. S. Deepa Shree ^3
1 PG Scholar, Government College of Technology, Coimbatore
²Associate Professor, Government College of Technology, Coimbatore
³ Assistant Professor, Jansons Institute of Technology, Coimbatore

ABSTRACT
Ferro cement elements are generally more ductile when compared to conventional reinforced concrete elements but post peak portion of load- deflection curve in bending test of Ferro cement elements reveals that failure occur either due to mortar failure in compression or due to failure of extreme layers of mesh. In this paper a study has been made on the ductility behaviour of hybrid Ferro cement elements by strengthening it in its tension zone by using GFRP layers and by adding polypropylene fibers into concrete. In present study, slab specimens of each 700 mm X 300 mm with varying parameters such as number of layers of mesh (2 & 3 bundled), layers of GFRP sheets (0 & 1) along with and without a specified proportion (0.30%) of polypropylene fibers were cast. Two point loading test was conducted on slabs and parameters such as ultimate moment capacity, ductility ratio and crack pattern were observed. From experimental results it was found that wrapping of GFRP in tension zone of slab increases confinement of bottom zone and using of fibre reinforced concrete has an influence on ductility and flexural capacities of ferrocement slabs.

Keywords: ferrocement slabs, GFRP wrapping, fibre reinforcement, ductility factors
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Research Paper by N.Balasubramanian,R.B.Karthika and Dr.R.Thenmozhi
Government College Of Technology, Coimbatore-641 013, India

ABSTRACT
This paper comprises of the experimental study of eight double skinned concrete filled steel tubular (DSCFT ) beam columns of concentrically placed circular sections filled with self compacting concrete. Tests on the specimens were made by applying eccentric loads. The main experimental parameters for beam-columns were slenderness ratio and load eccentricity. Testing of specimens investigates the behaviour on load deflection, confinement effect, and the strength of the columns. The experimental observations were shown by load-deflection curves. Various characteristics such as strength, stiffness, ductility and failure mode are discussed. The predicted load versus deformation relationships are in good agreement with beam-column test results. The DSCFT columns in-filled with SCC show good strength and ductility. Modified equations are suggested to find the ultimate compressive strength of DSCFT columns filled with SCC.

Keywords : Composite; Double skinned concrete filled steel tubular columns; D/t thickness, fabrication and casting, load deflection, ductility.

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This paper by SOURADEEP GUPTA (National University of Singapore) is aimed at discussing properties of geopolymer concrete, how these differ from properties of ordinary Portland cement, durability properties of fly ash based geopolymer concrete and its advantage when used as a construction material as well. Also some focus has been made on relevant issues that need to be solved and research needs to make it a better construction material.

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The main purposes of reinforcement in concrete roads are:

(i) to control the development and pattern of cracks in concrete pavement.

(ii) to reduce the spacing of joints. In general, joints and reinforcement in concrete structures are common design measures to cater for thermal and shrinkage movement. Hence, the inclusion of reinforcement allows
the formation of tiny cracks in concrete pavement and this allows wider spacing of joints.
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Good quality concrete starts with the quality of materials, cost effective designs is actually a by-product of selecting the best quality material and good construction practices. Following are 10 Things to remember during Concrete Mix Design and Concrete Trials.
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The temperature resisting cement (Refractory Castable) consists of fine and coarse agregates pre-mixed. When we pour the dry material into gunning machine directly, we normaly land up with 35% rebound waste of material.

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