Curing concrete is important to allow the cement hydration process to continue and develop strength over time. Proper curing ensures concrete reaches its designed strength and durability by controlling moisture loss. Common curing methods include water curing through ponding, sprinkling or wet coverings; membrane curing using plastic sheeting or curing compounds; and steam curing to accelerate strength gain. Curing should continue for at least 7 days for normal concrete and 14 days if blended cements are used. Inadequate curing can lead to reduced strength, increased permeability and poor durability.
Strength of concrete (for civil engineering) laxman singh
i have made all the slide for civil engineering and poly diploma civil.
these are 100% correct but in case of some error comment down or contact me on (laxmans227@gmail.com)
follow me for all updates
if u have any doubt fell free to ask on comment section
i upload new slides every sunday,
so keep calm and follow me(now).
software - power point presentation 2015
Strength of concrete (for civil engineering) laxman singh
i have made all the slide for civil engineering and poly diploma civil.
these are 100% correct but in case of some error comment down or contact me on (laxmans227@gmail.com)
follow me for all updates
if u have any doubt fell free to ask on comment section
i upload new slides every sunday,
so keep calm and follow me(now).
software - power point presentation 2015
Here, I attach a PowerPoint presentation created by me for a competition held by UltraTech. Have a look at this and feel free to share your views with me.
Here, I attach a PowerPoint presentation created by me for a competition held by UltraTech. Have a look at this and feel free to share your views with me.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
2. CURING OF CONCRETE
Lecturer Contents
•Introduction to curing of concrete
•Reasons to cure Concrete
•Duration of Curing of Concrete
•Methods of curing
- Water curing
- Membrane Curing
- Steam Curing
•Curing in Hot and Cold Weather
•Effect of curing on properties of concrete
•Consequences of inadequate curing
4. CURING
Curing is name given to the procedures used for
promoting the hydration of cement ,and
consists of a control of temperature and of
the moisture movement from and into the
concrete.
It has important role on strength development
and durability of concrete.
5. Concrete derives its strength as a result
of the chemical reaction of the mix water
and the cement, a reaction that starts at
the instant the two materials first come in
contact with each other and can continue
for long time.
6. Curing is done to control the rate and extent of
moisture loss from concrete to ensure an
uninterrupted hydration of Portland cement
after concrete has been placed and finished in
its final position.
Concrete that “dries” out will not reach its
design strength or meet specifications. The
longer the cure, the better the concrete.
7. Why Curing of Concrete is
Important
Cement requires a water/cement ratio
about 0.23 for hydration and a
water/cement ratio of 0.15 for filling the
voids in the gel pores. In other words, a
water/cement ratio of about 0.38 would be
required to hydrate all the particles of
cement and also to occupy the space in the
gel pores.
8. There are several important reasons why one should cure
concrete:
Concrete strength gain
Improves durability of concrete.
Harder, more abrasion-resistant surfaces
Enhanced Serviceability
Improved Microstructure
9. •Concrete strength gain - Concrete strength
increase with age as moisture and a favorable
temperature is present for hydration of
cement.
•An experimental investigation was conducted
by "Cement, Concrete & Aggregates Australia"
(CCAA) on the importance of curing.
10. •Figure-1 illustrates a comparison of the
strength of concrete at 180 days of moist
curing with various periods of moist curing
(0, 3, 7, 14 & 28 days) and then allowing it to
dry out. From the graph below, it can be
observed that concrete allowed to dry out
immediately, achieves only 40% of the
strength of the same concrete water cured
for the full period of 180 days.
11.
12. •Improved durability of concrete – The durability of
concrete is affected by a number of factors
including its permeability, porosity and absorptivity.
•Well cured concrete can minimize thermal, plastic &
drying shrinkage cracks, making concrete more
water tight, thus preventing moisture and water
borne chemicals from entering into the concrete
and thereby increasing its durability.
13. •Enhanced serviceability - Concrete that is
allowed to dry out quickly undergoes
considerable early age shrinkage. Inadequate
curing contributes to weak and dusty
surfaces having a poor abrasion resistance.
14. •Improved microstructure - Material properties are
directly related to their microstructure. Curing assists
the cement hydration reaction to progress steadily
and develops calcium silicate hydrate gel, which binds
the aggregates leading to a rock solid mass, makes the
concrete denser, decreases the porosity and
enhances the physical and mechanical properties of
concrete.
15. Duration of Curing
•The duration of curing of concrete depends
on the grade & type of cement, mix
proportion, desired concrete strength, shape
and size of the concrete member and
environmental & exposure conditions. The
duration may vary from few days to a month.
16. •In case of Ordinary Portland Cement (OPC),
Exposed surfaces of concrete shall be kept
continuously damp or in a wet condition by
ponding or by covering with sacks, hessian
cloth or other similar material and kept
continuously wet for at least 7 days from the
date of placing.
17. •In case of concrete where mineral
admixtures or blended cements are used, it is
recommended that the above minimum
periods may be extended to 10-14 days, for
assisting the secondary reaction.
19. Methods to Cure Concrete
Methods of curing concrete broadly fall into the
following categories:
1.Water curing-preventing the moisture loss from
the concrete surface by continuously wetting the
exposed surface of concrete.
2.Membrane curing-minimizing moisture loss from
the concrete surface by covering it with an
impermeable membrane.
3.Steam curing-keeping the surface moist and
raising the temperature of concrete to accelerate
the rate of strength gain.
20. Methods to Cure Concrete
1. Water Curing - is done by spraying or
sprinkling water over the concrete surface
to ensure that the concrete surface
remains continuously moist. This prevents
the moisture from the body of concrete
from evaporating and contributes to the
strength gain of concrete.
21. Ponding: This is the most common and
inexpensive method of curing flat surfaces
such as floor slabs, flat roofs, pavements and
other horizontal surfaces.
A dike around the edge of the slab, which may
be sub-divided into smaller dikes, is erected
and water is filled to create a shallow pond.
Care must be taken to ensure that the water
in the pond does not dry up, as it may lead to
an alternate drying and wetting condition.
Methods to Cure Concrete
1. Water Curing
23. •Sprinkling, fogging & mist curing: Using a
fine spray or fog or mist of water can be an
efficient method of supplying water to the
concrete surface especially during hot
weather, which helps to reduce the
temperature of concrete, eventually
conserving moisture inside the body of
concrete.
Methods to Cure Concrete
1. Water Curing
25. •Wet coverings: Water absorbent fabrics such
as hessian, burlaps, cotton mats, rugs etc.
may be used to maintain water on the
concrete surface by completely covering the
surface immediately after the concrete has
set. They must be continuously kept moist to
prevent the fabric from absorbing water
from the body of concrete, due to capillary
action.
Methods to Cure Concrete
1. Water Curing
27. 2. Impermeable Membrane Curing - Sometimes,
concrete works are carried out in places
where there is acute shortage of water .
•The quantity of water, normally mixed for
making concrete is more than sufficient to
hydrate the cement, provided this water is not
allowed to go out from the body of concrete.
•Concrete could be covered with membrane
which will effectively seal off the evaporation of
water from concrete.
Methods to Cure Concrete
28. •Formwork Leaving the formwork in place
during the early age of concrete is one of the
most efficient methods of curing, especially
for columns. However, the turn around time
of the formwork reduces considerably.
29. •Plastic sheeting Plastic sheets form an
effective barrier to control the moisture losses
from the surface of the concrete, provided
they are secured in place and are protected
from damage. They must be placed
immediately after the final set of concrete
without causing any damage to the surface.
•On flat surfaces like slabs, pavements, etc they
must be properly secured to the surface and
must extend beyond the edges of the slab, so
that they are not blown away by gusty winds.
30.
31.
32. •Membrane curing compounds - Curing
compounds are wax, acrylic and water based
liquids which are sprayed over the freshly
finished concrete to form an impermeable
membrane that minimizes the loss of
moisture from the concrete. These are cost
effective methods of curing where standard
curing procedures are difficult to adopt.
33. •Membrane curing compounds: When used to
cure concrete the timing of the application is
critical for maximum effectiveness. They must be
applied when the free water on the surface has
evaporated and there is no water sheen on the
surface visible. Too early application dilutes the
membrane, where as too late application results
in being absorbed into the concrete. Care must
be taken to avoid foot, machinery and vehicular
traffic over the concrete surface to prevent
damage of the coating.
34. 3. Steam Curing- Steam curing is a process
for accelerating the early hardening of
concrete and mortars by exposing it to steam
and humidity.
This type of system is most commonly used
for precast concrete products where standard
products are manufactured in the factory and
the turnaround time of the formwork is very
quick.
35. In the curing chamber, the control of
temperature and humidity is of prime importance
or else the concrete products are likely of
fracture, crumble and develop other problems
later in their service lives.
This type of curing systems are generally adopted
for railway sleepers, concrete blocks, pipes,
manhole covers, poles, pipe culverts, prestressed
precast concrete products, and so forth.
36. Curing in Hot weather
During hot weather, concrete must be
protected from excessive drying and from
direct sun and wind.
Curing materials which reflect sunlight to
reduce concrete temperature must be used.
Water curing is recommended and care
should be taken to prevent excessive stress
caused by alternative wetting and drying or
by cold water on warm concrete. Framed
enclosures of canvas tarpaulins or sun
shades may be used to protect the concrete
from direct sunlight.
37. Curing in Cold Weather
Some problems associated with temperature
below 4o C are:
•Freezing of concrete before adequate
strength is developed
• Slow development of concrete strength
• Thermal stresses induced by the cooling of
warm concrete to cooler ambient
temperatures.
38. •In cold weather, some procedures like
heated enclosures, insulating blankets &
curing compounds may be used.
•The temperature of fresh concrete must
be kept above 100C by using heated
raw materials and the curing shall be
continued for a longer period of time till
concrete gains the desired strength.
39. Conclusion
•The chemical reactions between cement
& water produces C-S-H gel which
bonds the ingredients of concrete, viz.
coarse & fine aggregates, mineral
admixtures, etc, and converts these
fragments into a rock solid mass.
•This is possible only if continuous curing
is done for at least 14 days; irrespective
of the type of cement used.
40. •To have a dense microstructure and
impermeability, prolonged curing is a
must which leads to enhanced
durability.
•Well designed concrete may give poor
durability if not properly cured and on
the other hand a moderately designed
concrete if well cured can give a better
durability. Hence importance of curing
should never be ignored.
Conclusion
41. •It has been observed that at several
sites, curing of concrete is left to the
decision and comfort of the unskilled
laborer.
•Site engineers & supervisors should put
an extra effort to ensure that curing is
not ignored at site & they should
provide the necessary resources to
maintain satisfactory levels of curing, by
using the best technique available at
site.
Conclusion
42. •Just as a new born baby, when it comes into
this world needs the utmost care for its
development and protection from this new
environment, in the similar manner, a freshly
placed concrete requires proper protection
and care from the encapsulating & aggressive
environment.
•Strictly adopting good curing practices at site
will help concrete to achieve the properties of
designed strength, enhanced durability,
improved microstructure and a long lasting
serviceability.
Conclusion