Filetype PDF | Posted on 13 Sep 2022 | 3 years ago
Authentication
digital resources
35x Filetype PDF File size 0.33 MB Source: media.neliti.com
INTERNATIONAL JOURNAL ON HUMAN COMPUTING
STUDIES
www.journalsresearchparks.org/index.php/IJHCS e-ISSN: 2615-8159|p-ISSN: 2615-1898
Volume: 02 Issue: 02 | 2020
Comparison of strength between normal concrete & admixture
concrete
1Akoba A.S, 2Phulari R.C, 3Kembhavi S.B, 4N.A. Gram
1,2,3 4
Department of Civil Engineering , Lecturer in Civil Engg. ääääïää ä
á
---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract cement concrete by adding some supplementary
Materials scientists, chemists, engineers, and substances named admixtures.
ï
The function of each admixture focuses on a specific
the concrete industry to improve our ability to control need, and each has been developed independently of
work times, workability, strength, and durability of the others. Some admixtures already have chemistry
Portland cement concrete by adding some that affects more than one property of concrete, and
supplementary substances named admixtures. some have simply been combined for ease of addition
The function of each admixture focuses on a specific during the batching process.
need, and each has been developed independently of Admixture is an essential component of any
the others. Some admixtures already have chemistry modern concrete mix, providing a compromise for the
that affects more than one property of concrete, and conflict between water and workability and
some have simply been combined for ease of addition performance of hardened concrete. The advancement
during the batching process. To better understand in admixture technology has played a significant role
recommended usage for various application of these in the development of concrete technologies. The
chemicals admixture in concrete, the present study is advanced PCE based admixtures have demonstrated
planned to be obtained more specific information in various performance benefits and technical
this direction. advantages over conventional super plasticizers in
In this investigation on performance of concrete with meeting the diversified challenging technical
GGBS and different PCE based water reducing requirements of various high performance concrete
admixture the tests on compressive strength and technologies for construction.
Workability of the concrete with Ordinary Portland In this investigation on performance of concrete with
cement and Portland pozzolana cement with GGBS GGBS and different PCE based water reducing
and admixture are carried out at different curing admixture the tests on compressive strength and
periods for M45 grade of concrete to conclude its Workability of the concrete with Ordinary Portland
behavior. cement and Portland pozzolana cement with GGBS
and admixture are carried out at different curing
1. INTODUCTION periods for M45 grade of concrete to conclude its
behavior.
1.1. General
Concrete is a composite construction material, 1.2. Admixtures:
composed of cement (commonly Portland cement)
and other cementitious materials such as fly ash and General:
slag cement, aggregate (generally a coarse aggregate ACI 116R-rr ò
made of gravels or crushed rocks such as limestone, material other than water, aggregates, hydraulic
or granite, plus a fine aggregate such as sand), water, cement, and fiber reinforcement, used as an
and admixtures. Materials scientists, chemists, ingredient of a cementitious mixture to modify its
á
ï
freshly mixed, setting, or hardened properties and
representatives have helped the concrete industry to
äó
improve our ability to control work times, tstäuò
workability, strength, and durability of Portland are used to enhance the properties of concrete and
9 2020, IJHCS | Research Parks Publishing (IDEAS Lab) www.researchparks.org | Page 51
INTERNATIONAL JOURNAL ON HUMAN COMPUTING
STUDIES
www.journalsresearchparks.org/index.php/IJHCS e-ISSN: 2615-8159|p-ISSN: 2615-1898
Volume: 02 Issue: 02 | 2020
mortar in the plastic and hardened state. Admixtures Polycarboxylate ether super plasticizer (PCE) or just
have long been recognized as important components polycarboxylate (PC), work differently from
of concrete used to improve its performance. sulfonate-based super plasticizers, giving cement
Function: dispersion by steric stabilization, instead of
In ACI 212-3R, the reasons for the use of admixtures electrostatic repulsion. This form of dispersion is
is outlined by the following functions that they more powerful in its effect and gives improved
perform: workability retention to the cementitious mix.
Increase workability without increasing water Polycarboxylate ether (a free flowing, spray-dried
content or decrease the water content at the same powder) high-range water reducer is the third
workability; generation super plasticizer and high performance
Retard or accelerate time of initial setting; polycarboxylate (purity 100%),specifically developed
Modify the rate or capacity for bleeding; a high range water reducing agent for concrete .It has
Reduce segregation; several aspects such as, comprehensive property
Reduce rate of slump loss; indexes , an environmental protection product with
Retard or reduce heat evolution during early high property, good dispersing property, high water
hardening; reducing rate ,good compatibility with various
Accelerate the rate of strength development at cements and good powder fluidity, it is especially
early ages; suitable to be used in dry-mixed mortar to improve its
Increase strength (compressive, property.
tensile, or flexural);
Decrease permeability of concrete; Uses:
Increase bond of concrete to steel Polycarboxylate ether is mainly used as a major
reinforcement; ingredient to produce a high-performance water
Increase bond between existing and new reducers or plasticizers for the following applications:
concrete; High performance concrete
Improve impact and abrasion resistance; Self-compacting concrete
Produce colored concrete or mortar Pump able or flow able concrete
Concrete containing silica fume, fly ash or
1.3. Chemical admixtures: blast furnace slag
Plasticizers or dispersants are additives that increase Specially shaped concrete elements
the plasticity or fluidity of the material to which they Architectural concrete
are added; these include plastics, cement, concrete, Lightweight concrete
wallboard, and clay. Although the same compounds
are often used for both plastics and concretes the Notes:
desired effects and results are different. Plasticizers
ï
or water reducers, and super plasticizer or high range naphthalene sulfonate. Unreliable rheological
water reducers, are chemical admixtures that can be behaviors may be experienced
added to concrete mixtures to improve workability. It should be stored at temperature 5-40 (40-
Unless the mix is "starved" of water, the strength of 104F). When it freezes; full strength can be restored
concrete is inversely proportional to the amount of after complete thawing and thorough agitation. Keep
water added or water-cement (w/c) ratio. In order to container closed when it is not in use. Do not store the
produce stronger concrete, less water is added product directly under sunlight.
(without "starving" the mix), which makes the The shelf life is twelve (12) months.
concrete mixture less workable and difficult to mix, LITERATURE REVIEW
necessitating the use of plasticizers, water reducers, Admixtures-enhancing concrete
super plasticizers or dispersants. performance: Mario Collepardi, Enco,
Engineering Concrete, Ponzano Veneto (Italy);
1.3.1. Polycarboxylate ether: Studied that super plasticizers are the most
9 2020, IJHCS | Research Parks Publishing (IDEAS Lab) www.researchparks.org | Page 52
INTERNATIONAL JOURNAL ON HUMAN COMPUTING
STUDIES
www.journalsresearchparks.org/index.php/IJHCS e-ISSN: 2615-8159|p-ISSN: 2615-1898
Volume: 02 Issue: 02 | 2020
important admixtures enhancing concrete dispersion capability and flexibility in molecular
performance. The development of new design, PC admixtures enable the production of
superplasticizers during the last decades has concrete at low water cementitious ratio with
determined the most important progress in the high workability, use of more blending
field of concrete structures in terms of higher materials, and to cater to different challenging
strength, longer durability, lower shrinkage and requirements, such as high strength, high
safer placement particularly in elements with durability, high workability and long
very congested reinforcement. The progress from workability retention, etc. Some cases of
sulphonated polymer to polycarboxylate has advanced admixture application in high
resulted in higher water reduction at a given performance concrete infrastructural
workability and lower slump loss. More recently construction, such as marine bridges, high-rise
poly-functional super plasticizers have been buildings, water treatment plants in Asia, are
developed which are able to completely keep the presented as well.
initial slump for at least 1 hr. without any New trends in the development of chemical
retarding effect on the early strength. Moreover, admixtures in japan by Etsuo Sakai, Atsumu
multi-purpose and poly-functional super Ishida and Akira Ohta: This paper describes the
plasticizers have been invented which are able to history and new trends in the development of
reduce drying shrinkage. The recent progress of chemical admixtures in Japan. PC (polycarboxylic
super plasticizers was examined in this paper. acid)-based agents are the main products in the
Compatibility Issues of Nsf-Pce Super super plasticizer market. A low-stickiness type
plasticizers with Several Lots of Different PC-based super plasticizer has been developed
Cement Types (Long-Term Results) by Luigi based on the conventional PC-based super
Coppola, Sergio Lorenzi and Alessandra plasticizer. The flowing speed of concrete with
Buoso: This paper focuses on the compatibility low stickiness type PC-based super plasticizer is
issue between cement and chemical admixtures. faster than that with the conventional PC-based
Different kind of chemical admixtures were super plasticizer. By addition of a new viscosity
considered belonging to naphthalene (NSF) and agent consisting of a mix of anionic and cationic
polycarboxylate-based families. Five lots of six surface active agents, the three- dimensional
different cements widely spread in Italy were reticulation structures are formed in fresh
considered. Mortars and concretes were cement paste and the viscosity of the cement
manufactured by varying super plasticizer paste can be increased and segregation can be
dosage to achieve fixed workability at the end of prevented. The hydration of cement in sludge
mixing. Flow retention up to sixty minutes and water is controlled by addition of a set-retarder,
tendency to entrap air in the mortars and and the specific surface area of cement does not
concrete were measured to evaluate increase while a large amount of unreacted alite
performances in terms of water reduction and remains in the sludge water. Recycling of
workability loss of each chemical admixture. concrete at ready mixed concrete plants is
Compressive strength at 1, 7 and 28 days was possible without adversely influencing the
also considered. The rheological and mechanical properties of concrete when sludge water with
behavior of manufactured concretes showed the set-retarder containing gluconate salt is used.
good agreement with results collected on The slurry type and powder type calcium
mortars. aluminate based accelerator (CA) and
Advanced admixture applications in high calciumsulfoaluminate based accelerator (CSA)
performance concrete infrastructure for shotcrete have been developed. In the case of
construction Jiang Jiabiao PhD W. R. Grace CA, the final setting time of the mortar is
(Singapore) Pte. Ltd., Singapore: This paper accelerated by increasing the dosage. By adding
discusses new generation poly-carboxylate (PC) of CSA, both the initial and final setting times of
based admixture technologies and its mortar are shortened with increased dosages.
application in high performance concrete for Effect of superplasticizer and shrinkage-
infrastructure building. With the powerful reducing admixtures on alkali-activated slag
9 2020, IJHCS | Research Parks Publishing (IDEAS Lab) www.researchparks.org | Page 53
INTERNATIONAL JOURNAL ON HUMAN COMPUTING
STUDIES
www.journalsresearchparks.org/index.php/IJHCS e-ISSN: 2615-8159|p-ISSN: 2615-1898
Volume: 02 Issue: 02 | 2020
greater fluidity retention of the mixtures
pastes and mortars by M. Palacios, F. Puertas: containing the polycarboxylate-based HRWRA.
This paper shows how several The incorporation of a water-reducing agent in
superplasticizers (polycarboxylates, vinyl mixtures made with polynaphthalene
copolymers, melamine and naphthalene-based) sulphonate- based HRWRA is shown to increase
and shrinkage reducing (polypropylenglycol lateral pressure development of the plastic
derivatives) admixtures affect the mechanical concrete over time.
and rheological properties and setting times of
alkali-activated slag pastes and mortars. Two
activator solutions, waterglass and NaOH, were
used, along with two concentrations4% and 1.
5% of Na2O by mass of slag. All admixtures, with 1.1. Cement:
the exception of the naphthalene-based product,
lost their fluidifying properties in mortars Two types of cements were used during the
activated with NaOH as a result of the changes in experimental investigation:
their chemical structures in high alkaline media. 1. Ordinary Portland Cement 53 grade (Brand:
The difference in the behavior of these Ultra Tech) confirming to IS: 12269-1987 in
admixtures when ordinary Portland cement is case of control mix. The physical properties
used as a binder is also discussed in this paper. of the cement obtained on conducting
Effect of w/cm and high-range water- appropriate tests as per IS:269/4831 and
reducing admixture on formwork pressure the requirements as per IS:12269-1987
and thixotropy of self-consolidating concrete 2. Portland Pozzolana Cement 53 grade
by Kamal H. Khayat and Joseph J. Assaad: An (Brand: Ultra Tech) confirming to IS 1489:
experimental program was undertaken to 1991 (Part 1) in case of control mix is used
evaluate the effect of water- cementitious 1.2. GGBS:
material ratio (w/cm) and type of high- range GGBS was brought from Ultra TECH
water-reducing admixture (HRWRA) on the Ready Mix Concrete plant. Properties of GGBS
development of formwork pressure that can be are as per specification.
exerted when using self-consolidating concrete
(SCC). Test results show that the variations in
lateral pressure and thixotropy of SCC are 1.3. Fine Aggregate:
significantly affected by the w/cm. Irrespective
of the HRWRA type, mixtures proportioned with Locally available clean river sand was
0.46 w/cm exhibited greater initial pressure and sieve analyzed and tests for specific gravity were
lower thixotropy compared with mixtures made carried out. The fine aggregate used belongs to
with a w/cm of 0.40 and 0.36. This is related to Grade II.
the higher water content and lower coarse
aggregate volume in concrete proportioned with
the higher w/cm, which can lead to a reduction 1.4. Coarse Aggregate:
in shear strength properties of the plastic Crushed granite of 20 mm maximum size
concrete. The rate of pressure drop and increase and retained on IS: 480 sieves have been used as
in thixotropy with time, however, were greater coarse aggregate; approximately 36.45% (390
in mixtures made with a higher w/cm. This is
tr
attributed to the lower HRWRA demand that can xuäww¨ xzr
lead to sharper fluidity loss with time. For any aggregate passing 10 mm sieve size were
given w/cm, the type of HRWRA appears to have combined to obtain coarse aggregate in the
a limited effect on initial lateral pressure. investigation. The sieve analysis of aggregate
Compared with naphthaleneand melamine- conforms to the specifications of IS 383:1970 for
based HRWRA, the use of polycarboxylate- graded aggregates. Test results are given in
based. HRWRA in SCC resulted in lower rate of Table below.
pressure drop with time. This is reflected by the
9 2020, IJHCS | Research Parks Publishing (IDEAS Lab) www.researchparks.org | Page 54
no reviews yet
Please Login to review.
