Concrete is the 1 of the oldest building stuffs created by homo. It is used widely around the universe in assorted signifiers, particularly in constructing building. Many people felt that concrete will be continued to be the primary edifice stuff for several decennaries.
By and large, the usage of concrete as a edifice stuff is the most of import component than other stuffs for most of edifice constructions. The use of concrete does hold many advantages, either during the building procedure until the usage in the constructions. This is because this stuff is easy available and can besides supply a strong edifice construction every bit good as being effectual in a cost building.
However, the concrete as a edifice stuff has a certain disadvantages. Its physical feature which is brickle causes itself to be unable to run into the needed strength in all conditions. Besides, concrete has a low tensile strength, low ductileness, less stable volume, ratio of strength towards little weight, high permeableness, high drying shrinking and hapless opposition to some chemicals.
Therefore, alterations must be made to better the public presentation of concrete so that it can be used more efficaciously. In the line with current engineering, there are many alterations being done to the concrete to better and heighten the belongingss of concrete. The usage of additives in the concrete mix is one of the engineerings that have been used in the building industry to better the belongingss of concrete belongingss such as strength, workability, lastingness, bleed, weirdo and so on.
One of the efforts to better these belongingss is to use the polymer in the concrete. Concrete technological developments besides give the different types of polymer additives that can impact the nature of concrete and its application.
By and large there are three types of polymerized concrete vary by method of production. The first group is polymer-modified concrete, the 2nd group is polymer impregnated concrete, while the 3rd group is polymer concrete. We will find the features of each of group of polymerized concrete.
Aim
To cognize about concrete and its features
To cognize about polymer and its features
To analyze about polymer that uses in concrete
To find a group of polymerized concrete
LITERATURE REVIEW
Concrete
Introduction TO CONCRETE
The use of concrete today is the of import component in a building industry. In general, concrete is a stuff made from a mixture of cement, sums, sand and H2O at a specified rate or ratio designed. In certain event, an additive is assorted to bring forth a concrete with certain character. Mixture designs that normally used, is defined as the compressive strength standards in a period of 28 yearss and designed harmonizing to class. For illustration, grade 30 of concrete has strength 30 N/mm2 at 28 yearss. ( Blackledge, 1987 )
Because of concrete is one of the most abundant stuffs used, fabricating techniques of good quality concrete must be understood and carefully observed. The quality of concrete is dependent on the quality of the natural stuffs used, the mixture, the water-cement ratio, the manner of commixture, the manner to reassign, the manner to stack ( puting the concrete ) , how to pack the assorted concrete, the quality of the cast and the method of saving.
If the natural stuffs used have low quality or the readying which does non follow the regulations that have been set, so as a consequence, concrete will be in low quality. Besides, it may ensue as the concrete can non keep a burden as expected. If this happens, the consequence is really bad.
Elementss IN CONCRETE
Cement
Cement is a stuff which has cohesive and adhesion belongingss that can adhere stones into a solid organic structure. Cement is produced from a mixture of clay and limestone. In general, the production of cement is including clay and limestone that will be milled and heated up to be coal or cinder in the rotary burner. The cinder will be ground into all right dust and a small gypsum will be included at the terminal of blending. ( R.H Elvery, 1969 )
There are many types of cement made in a mill for a peculiar intent, and to run into the demands of the class. The types of chief cement are:
a. Ordinary Portland Cement
B. Modified Cement
c. Rapid Hardening Cement
d. Low Heat Cement
e. Sulphate Resisting Cement
The content ratio of chemical substances in assorted types of cement influences the belongingss and the name of the cement. Chemical composing of the Portland cement is shown in Table 1 and the major compounds of Portland cement are shown in Table 2. ( M.S Shetty, 1986 )
Table 1: Types of assorted oxide in Portland cement ( Beginning: M.S Shetty, 1986 )
Oxide
Percentage from the net weight ( % )
Lime, CaO
60.0 – 67.0
Silica, SiO2
17.0 – 25.0
Alumina, Al2O3
3.0 – 8.0
Iron oxide, Fe2O3
0.5 – 6.0
Magnesium oxide, MgO
0.1 – 4.0
Sulfur Trioxide, SO3
0.4 – 1.3
Bases, ( K2O, Na2O )
1.0 – 3.0
Table 2: Main compound in Portland cement ( Beginning: M.S Shetty, 1986 )
Name of chemical compound
Formula
Simple Formula
Percentage of content ( % )
Tricalcium silicate
3CaO.SiO2
C3S
54.1
Dicalcium silicate
2CaO.SiO2
C2S
16.6
Tricalcium aluminate
3CaO.Al2O3
C3A
10.8
Tetracalcium aluminoferrite
4CaO.Al2O3.Fe2O3
C4AF
9.1
Gypsum and others
–
–
9.4
Water
Water is needed in concrete for hydration and workability of concrete. The H2O used must be free from inordinate sums of drosss because it will has an inauspicious consequence on the procedure of indurating, volume stableness, lastingness, stain and corrosion of support. Some of these drosss are acerb, alkalic, sulphate, clay, chloride and others.
Different types of H2O available on Earth are doing the demand to happen the H2O that can be used for concrete plants. The H2O used for blending concrete should be clean. It can be taken from any approved beginning. It should besides be free from soil and suspended solids, organic affair and sea salt. Water that incorporating algae is non suited for concrete because algae is trap the air and high air content will cut down the strength of concrete. Increased algae from 0.09 % to 0.23 % will increase the air content of 10.6 % and resulted in a decrease of concrete strength by 50 % . ( Mehta, 1991 )
The usage of sea H2O in strengthened concrete and prestressed concrete shall non be used. It will be a danger of corrosion of support due to chloride content in the H2O, even to the concrete as the crumbly disfigure work. ( Mehta, 1991 )
In the context of Malaysia, tap H2O can be used without jobs because it is non merely potable but assured quality and from an approved beginning.
Sum
Aggregate is an of import ingredient in concrete. It besides plays an of import function in determining the strong assorted concrete and resilient while cut downing shrinking and more economical. ( M.S Shetty, 1986 ) In a concrete mix, step of sum non merely restricting the strength of concrete, but the sum belongingss besides have a important consequence on the lastingness, workability and behaviour of concrete constructions. ( Neville, 1981 )
There are two groups of sums which are the harsh sum and all right sum. All right sum ( sand ) has a size less than 5 millimeters and harsh sum ( normally called stone ) has a size greater than 5 millimeter.
WORKABILITY OF CONCRETE
The strength of concrete at the rates specified mixture strongly influenced by the grade of concentration. Therefore, a really high workability of concrete is needed to bring forth a strong concrete. The term used is to depict the pleasances of workability of concrete that will be compacted. Cement content, an overall of sum scaling and practical signifier of sums will impact the workability of concrete. ( Blackledge, 1987 )
The factors that impacting the workability of concrete are including cement, sums, water-cement ratio, additives, temperature and clip. The trials that normally used to mensurate the workability are debris trial, compactness trial and vee-bee trial on consistence clip ( VB ) .
Workability of concrete can be said to be good if it fulfills the undermentioned features:
Can be easy compacted to take trapped air to accomplish the strength and huskiness.
Can be easy transported and placed by such methods as utilizing trucks, carts and pumps.
Flow to every corner and fills the full cast despite holding the support construction closely.
Can bring forth a good coating during the cast was removed without holding a clean infinites between the concrete like honeycomb.
STRENGTH OF CONCRETE
The strength of concrete is one of the of import belongingss of concrete to supply a comprehensive overview on the quality of concrete because strength is straight related to the construction of hard-boiled cement paste. ( Neville, 1981 )
In Figure 1, the strength of concrete additions with age and increase strength continues for some clip. However, the concrete at 28 yearss old is used as a step of strength. The addition in compressive strength of concrete is extremely dependent on temperature and humidness during a degree of hardening of concrete. Water-cement ratio is among the chief factors that control the strength of the concrete.
Figure 1: Relationship between the strength of concrete and water-cement ratio
( Beginning: EngineeringIntro.com, 2012 )
Besides taking into consideration the water-cement ratio, the strength of concrete is besides really dependent on the method or procedure. For illustration, in the procedure of fixing the concrete, if there is a alteration in quality of ingredients that is assorted, so it will impact the strength of concrete produced which is same as concrete that add with additives.
Trial ON CONCRETE
Trials on concrete are of import in concreting work either before or after the concrete advancement. Workability of concrete is really of import in finding the strength and lastingness of concrete, every bit good as quality of stuffs used and the commixture ratio harmonizing to the specifications. The trial that is normally done to mensurate the pleasance of work at building sites and in the research lab is debris trial, compactness trial and vee-bee consistence trial ( VB ) . ( Civil Engineering Portal, 2012 )
Meanwhile, to find the strength of concrete, compressive trials were conducted on samples taken from the regular hexahedron of concrete mix used for concreting work. The regular hexahedron of concrete are harmonizing to the specifications in the concrete compaction proving process.
RELATIONSHIP BETWEEN COMPRESSIVE STRENGTH AND FLEXURAL STRENGTH OF CONCRETE
Compressive and tensile strength ( flexing ) is associated closely linked. The ratio of compressive strength and tensile strength is dependent on the general degree of the concrete strength. In other words, when the compressive strength is increased, flexural strength besides increased but at a worsening rate.
For Figure 2, the flexural strength by and large is taken about one-tenth or 10 % of the compressive strength but different sums cause this rate to alter. Then the compaction trial is merely a general usher to the strength of this tenseness or bending. There are several factors that may be associated with this status. The tensile strength of concrete is more sensitive to the saving of the less sensible than the compressive strength of concrete.
Figure 2: Relation between flexural strength and compressive strength
( Beginning: A.K. Padmini, K. Ramamurthy, 2009 )
Figure 3: Modulus of snap as a map of compressive strength
( Beginning: Federal Highway Administration ( FHWA ) , 2006 )
For Figure 3, compressive strength is besides being expressed in modulus of snap of concrete. Few equations are considered to cover the whole information when many empirical equations for foretelling modulus of snap have been proposed by many research workers. The mechanical belongingss of concrete are extremely dependent on the belongingss and proportions of binders and sums which is one of the grounds that should be considered.
Polymer
Polymers are the stuffs that most widely used in of import engineering in the twentieth century. Besides, polymers besides play an of import function in day-to-day life such as vesture, place contraptions, automotive, communicating engineering and so on. Similarly, in metal and ceramic engineering, the survey of polymers has a construct of applications, which is to understand the construct in the fabrication procedure, the construction of the physical and mechanical belongingss of the stuff formed.
In general, polymers are supermolecules that are formed when a big figure of molecules or monomers that combines in such a concatenation. Monomers are moving in a little unit reiterating the chemical reactions to organize a long concatenation. A concatenation may happen in the signifier of additive or branched concatenation within 3-dimensional.
STRUCTURE OF POLYMER
Polymer can be divided into several groups of construction such as additive polymer, branched polymer, star polymer, dendrimer polymer and cross-linked polymer. These constructions are formed depending on the manner C bond that owned by a polymer is formed.
Degree centigrades: UsersSiti RashidahDesktopsolid province physicsLINEAR.gif
Figure 4: Linear polymer
Figure 5: Branched polymer
Figure 6: Cross-linked polymer
Figure 7: Star polymer
Figure 8: Dendrimer polymer
( Beginnings: Polymer Science Learning Center, 2005 )
Figure 4 is showed a additive polymer. The monomeric units in additive polymer are linked linearly together but non in a long concatenation. For Figure 5, side ironss of bifurcate polymer are attached to the anchor of the molecular concatenation. Following, cross-linked polymer is a web of polymer ironss which is in a formation of a 3D. In Figure 7, star polymer is a supermolecule holding a little nucleus of molecules ( branch point ) with subdivisions radiating from the nucleus. Last, in Figure 8, dendrimer polymer is a hyper-branched and mono-disperse molecules that give a good belongings due to its construction. ( McGraw-Hill S & A ; T Dictionary, 2012, Klajnert B. and Bryszewska M. , 2001 )
PROPERTIES OF POLYMER
Properties of the polymer chiefly depend on the geometry of the polymer bond. There are three chief types of polymer belongingss that have been identified as the thermoplastic belongingss, thermosetting and elastomeric.
THERMOPLASTIC POLYMER
Thermoplastic polymer is a polymer which must be diluted at a high temperature for processing and after chilling, the polymer stuff will retain to its form. In add-on, it besides may be diluted once more and formed into needed form without altering its original characteristics. Normally it consists of a long concatenation additive polymer incorporating C atoms bond formed by covalent bonds. Many thermoplastic stuffs can be melted in the temperature scope from 100 A° C to 250 A° C.
ELASTOMER POLYMER
Elastomer polymer which is gum elastic is a polymer with elastic belongingss which can alter its dimensions when subjected to tensile forces. When the tenseness is released, the polymer can be returned to its original dimensions. However, this elastic belongings will lose consequence when subjected to high temperatures. Elastomeric polymer which foremost known is natural gum elastic latex extracted from the tropical gum elastic tree called as Hevea Brasiliensis through vulcanisation with S. This material consists of primary stuff which is poly ( cis-isoprene ) mixed with some other constituents, including proteins and fats. The construction of the repetition unit of poly ( cis-isoprene ) is shown in Figure 6.
Figure 9: Structure of repetition unit of poly ( cis-isoprene )
( Beginning: Blackledge, 1992 )
THERMOSET POLYMER
Thermoset polymer normally has a cross-bonding construction concatenation and it can be formed by reaction of heat or chemical. The nature of the thermoset polymers normally has a opposition to thermic reactions of stable and strong rigidness. However, thermoset polymers can non run at high temperatures but will decompose and break up.
Polymer IN CONCRETE
There are three chief groups of polymerized concrete. The chief difference between the three groups is in footings of the readying method. However, all of these three methods have the same aim which is to better the general failings in apparent concrete. Besides, the advantages of the polymer itself are besides the major choice standards for this qualifier agent. Polymer has good characteristics such as the strength, snap, high adhesion belongingss and good lastingness. The chief groups of the polymerized concrete are polymer concrete, polymer impregnated concrete and polymer modified concrete.
POLYMER CONCRETE
For this type of concrete, cement is replaced with the polymer stuff. Polymer concrete is made by adding a monomers or rosin system together with sums. Polymerization reaction that occurs in the concrete will alter monomers or rosin system to a hardening of the polymer construction. It is besides known as rosin concrete. ( Mehdi, 2011 )
POLYMER IMPRAGNATED CONCRETE
Polymer impregnated concrete generated by absorbing the monomers into an already hard-boiled concrete until it reached impregnation in the concrete, in which all the pores, nothingnesss and clefts will be filled by the monomers. This procedure will be followed by the polymerisation procedure. Porosity factor looking in the concrete will act upon the soaking up of monomer.
The procedure of make fulling monomers into a concrete is done by agencies of concrete drying and warming to take the H2O content in it. Later on, it is placed in a vacuity and submerged under certain force per unit area followed by a polymerisation procedure with thermic catalytic method or gamma beams. ( Fowler, 2012 )
POLYMER MODIFIED CONCRETE
Polymer modified concrete is formed when Portland cement and sums are combined together during a commixture of polymer. Then, the concrete is cured in a damp chamber. Besides of being able to make full the pores of the air, it is able to organize the polymer latex binder atoms every bit good as in the function of the cement paste in concrete. This type of concrete as good is known as polymer Portland cement concrete ( PPPC ) and latex modified concrete. Normally, polymer modified concrete is ever being used because of its method that is practical and easy to bring forth. ( American Concrete Institute, 2009 )
Decision
As a decision, we know about the concrete and its features within its map in the building as a chief element/material. Besides, we besides have studied about polymer, its features, constructions and every bit good as its function in the concrete as a alteration to better the strength and other features of concrete. In add-on, we have determined the types or group of polymerized concrete that have been created and their features as good.
