X
Courses » Hydration, Porosity & Strength of Cementitious Materials
Unit 10 - Week 8 - Concrete
Announcements Course Ask a Question Progress FAQ
Register for Register for Certification exam Certification exam
Course outline
How to access the portal Assignment 0
Week 1 - General Discussion on Concrete and its Properties
Week 2 - Aggregates, Mix Design of concrete and Chemical Admixtures
Week 3 - Portland Cement Based Paste Systems
Week 4 - Portland Cement Based Paste System (contd.) and heat of hydration
Week 5 - Mineral Admixtures
Week 6 - Mineral Admixtures (Contd.)
Due on 2019-03-27, 23:59 IST.
1) 1 point
2) 1 point
3) 1 point
Assignment-8
The due date for submitting this assignment has passed.
As per our records you have not submitted this assignment.
Identify the FALSE statement with regard to the stress strain curve of concrete
Prior to the external loading, micro-cracks are not present in hydrated cement paste of the concrete
Concrete can be reasonably assumed to show linear elastic behavior until stress level of 30% of ultimate stress
At the stress level of 50% of ultimate stress, micro cracks start propagating but not in mortar phase
The stress-strain curve of concrete doesn’t show a definite yield point No, the answer is incorrect.
Score: 0
Accepted Answers:
Prior to the external loading, micro-cracks are not present in hydrated cement paste of the concrete Identify the TRUE statement with regard to the modulus of elasticity of concrete
As per IS 456:2000, the modulus of elasticity of concrete can be estimated using the actual strength of cubes determined during construction
Modulus of elasticity of concrete is influenced by the moisture condition of specimen Dynamic modulus of elasticity is obtained from the slope of the tangent drawn at the non-linear part of the stress-strain curve
Modulus of elasticity of concrete is independent of the modulus of elasticity of aggregate No, the answer is incorrect.
Score: 0
Accepted Answers:
Modulus of elasticity of concrete is influenced by the moisture condition of specimen Identify the FALSE statement with regard to the strength of concrete
A project of In association with
Funded by
© 2014 NPTEL - Privacy & Terms - Honor Code - FAQs -
Hydration, Porosity & Strength of Cementitiou... https://onlinecourses.nptel.ac.in/noc19_ce03/un...
1 of 4 Friday 10 May 2019 10:22 AM
Powered by Lecture 35 -
Behavior under load
Lecture 36 - Curing of concrete Lecture 37- Stress strain behaviour Lecture 38 - Durability of concrete - I Lecture 39 - Durability of concrete - II - Specifications Lecture 40- Evaluation and overview Quiz : Assignment-8 Assignment 8-Solution
4) 1 point
5) 1 point
6) 1 point
7) 1 point
platens and the specimen.
The observed strength is related to the rate of loading No, the answer is incorrect.
Score: 0
Accepted Answers:
The strength measured using a cylindrical specimen (100mm x 200mm) is higher than that measured using a cube (150mm side).
Identify the TRUE statement with regard to the strength of the concrete
Strength of concrete (S) can be modelled as S = S0[exp(-kp)], where S0 and p are the strength of coarse aggregate and the porosity of hardened cement paste, respectively, with k being an empirical constant
Under moist curing condition, complete hydration is achieved when concrete achieves more or less its 100% strength
If the rate of application of load is low, the strength of specimen will be low due to the effect of creep
Strength gained by concrete is directly proportional to the w/c ratio in concrete No, the answer is incorrect.
Score: 0
Accepted Answers:
If the rate of application of load is low, the strength of specimen will be low due to the effect of creep Identify the FALSE statement with regard to the curing of concrete
Curing is performed to prevent the loss of moisture from the concrete Steam curing is used in case where higher early strength is required
Gain in strength of concrete will happen only when concrete remains moist with a minimum relative humidity of 80% and favorable ambient temperature
Membrane curing is achieved by covering the surface of concrete with wet cloth or by wet sand
No, the answer is incorrect.
Score: 0
Accepted Answers:
Membrane curing is achieved by covering the surface of concrete with wet cloth or by wet sand Identify the FALSE statement with regard to the maturity of concrete
The datum temperature for computing maturity is considered as -5°C Maturity is the function of time and temperature
As maturity of concrete increases, its strength gain also increases
Batches of same concrete mixtures of same maturity will attain the same strength regardless of the time-temperature combinations
No, the answer is incorrect.
Score: 0
Accepted Answers:
The datum temperature for computing maturity is considered as -5°C Identify the TRUE statement with regard to the durability of concrete
Permeability of concrete is independent of the durability of concrete
Ingress of harmful material occurs through the pores and not from the ITZ of the concrete Concrete in tidal zone generally cracks due to freeze-thaw or chemical decomposition of hydrated cement
Hydration, Porosity & Strength of Cementitiou... https://onlinecourses.nptel.ac.in/noc19_ce03/un...
2 of 4 Friday 10 May 2019 10:22 AM
8) 1 point
9) 1 point
10) 1 point
Concrete in submerged zone generally cracks due to the corrosion in steel No, the answer is incorrect.
Score: 0
Accepted Answers:
Concrete in tidal zone generally cracks due to freeze-thaw or chemical decomposition of hydrated cement Identify the TRUE statement with regard to the environmental exposure condition of
concrete
IS 456:2000 classifies four environmental exposure conditions based on the exposure of concrete to environment
Japanese code classify three environmental exposure conditions based on the corrosive nature of environment
Only EN-1992 includes sulfates in the classification of environmental exposure condition Only ACI 318M includes chemical attack in the classification of environmental exposure condition
No, the answer is incorrect.
Score: 0
Accepted Answers:
Japanese code classify three environmental exposure conditions based on the corrosive nature of environment
Identify the TRUE statement with regard to the IS 456:2000 durability specification
Plain and reinforced concrete exposed to extreme environmental condition require a minimum grade of M25 concrete to be used
In order to mitigate AAR, the maximum alkali content is specified as 0.8 kg/m3of concrete In RCC, the maximum total acid soluble chloride content in cement is specified as 0.60%
In order to mitigate sulfate attack, the maximum total water soluble sulfate content is specified as 4% by mass of cement
No, the answer is incorrect.
Score: 0
Accepted Answers:
In order to mitigate sulfate attack, the maximum total water soluble sulfate content is specified as 4% by mass of cement
Identify the FALSE statement with regard to the durability of concrete
Map cracking is the pattern of cracking observed in alkali aggregate reaction distress With cyclic exposure to freezing and thawing, ‘pop-outs’ of aggregates are often seen in damaged concrete
In sulfate attack, cracks are often seen on hydrated cement paste as well as on the aggregate of concrete
Chloride attack result in reinforcement corrosion which causes the spalling of concrete along the reinforcement
No, the answer is incorrect.
Score: 0
Accepted Answers:
In sulfate attack, cracks are often seen on hydrated cement paste as well as on the aggregate of concrete
