Materials and Mix Proportioning Essay

Chapter 3

MATERIALS AND MIX PROPORTIONING

3.1 Introduction

A comprehensive reappraisal of the literature related to the synthesis of non-conventional binder complexs for civil technology applications by geopolymer engineering and their public presentation rating was presented in the old chapter. ‘Literature review’ being prelude to any research, facilitated placing the countries and range for farther probes in this field and aims of present research.

Word picture is a procedure of finding the typical properties/ features of the stuffs proposed to be used in the survey. It is a outstanding activity undertaken to measure the relevant belongingss of the stuffs with mention to peculiar application.

Mix proportioning is the procedure of finding the right combination of component stuffs that will bring forth a concrete mixture with the coveted features at the lowest possible cost. Even with ordinary concrete the procedure is non easy because it involves the art of equilibrating assorted conflicting demands. Extensive research lab proving must frequently be carried out before a satisfactory proportion of stuffs are arrived at. Explicating GPC is a more complex operation than explicating conventional concrete because the figure of parametric quantities to be managed is larger. Assorted surveies have been carried out to look into the basic belongingss of different stuffs used in this probe.

The processing operations can be arranged in the undermentioned series of stairss.

1. foremost, it is necessary to take the components, doing usage of available local stuffs.
2. One must so make up one’s mind in what proportions the components of the concrete have opportunity of fulfilling the specification.
3. The farinaceous skeleton must be optimized by empirical or theoretical methods.
4. The binder ( s ) – alloy ( s ) system must be investigated.
5. Finally, it is necessary to prove the rheological behaviour of the geopolymer concrete, so its mechanical features and lastingness facets.

3.2 Materials

The stuffs used for doing fly ash-based geopolymer concrete specimens are low-calcium dry fly ash ( category F ) , land granulated blast furnace scoria as the beginning stuff, sums, alkalic liquids ( combination of Na hydrated oxide and Na silicate solutions ) , H2O and superplasticiser.

3.2.1 Fly ash

Fly ashes are the little atoms collected by dedusting systems of coal firing power workss. Fly ash can hold different chemical and stage composings because they are entirely related to the type and sum of drosss contained in the coal burnt in the power works. ASTM classifies them as category F and category C fly ashes based on the chemical composing. Class F fly ash is normally produced in power workss firing anthracite or sub-bituminous coal and are characterized by low Ca content. Most fly ashes are pozzolanic stuffs. The CaO content is less than 10 % in category F fly ash and is approximately 15 to 35 % in category C fly ash. For the present probe fly ash used was corroborating to ASTM Class F obtained from Raichur Thermal Power Station, Shaktinagar, Karnataka. The physical and chemical belongingss of the fly ash are given in Table 3.1.

Table 3.1: Physical and Chemical belongingss of Fly ash

Properties	Experimentalvalues	Valuess as per IS:3812-2003 [ 72 ]
Physical Properties
Specific gravitation	2.00	–
Bulk denseness, g/cc	1.20	–
Delicacies, m2/kg	290	–
Coloring material	Cream white
Chemical Properties
Oxide composing ( % by mass )
Silicon dioxide ( SiO2)	58.52	70 % min.
Ferric oxide ( Fe2Oxygen3)	6.20
Aluminium oxide ( Al2Oxygen3)	22.48
Calcium oxide ( CaO )	5.90	–
Magnesium oxide ( MgO )	0.81	5 % soap.
Titanium dioxide ( TiO2)	0.27	–
Potassium oxide ( K2O )	0.42	–
Sulphur trioxide ( SO3)	0.55	–
Alkali oxide ( Al2Oxygen3)	0.40	1.5 % soap.
Loss of ignition ( LOI )		12 % soap.

3.2.2 Ground granulated blast furnace scoria

GGBS is the by-product of the industry of Fe. Molten scoria, a secondary merchandise of sintering of the natural stuffs which when quenched under high force per unit area H2O jets, granulates. The granulated scoria when land to really all right pulverization or less than 45 micrometer with a ( Blaine ) specific surface of 400-600 m²/kg is GGBS. It is glassy, non-metallic stuff consisting largely silicates and Ca oxide combined with other oxides/ bases. It possesses both cementitious and pozzolanic belongingss ; further it is a latent hydraulic stuff which can straight respond with H2O, but in the presence of an alkalic activator to originate hydration. Due to its latent hydraulic belongingss, GGBS has considered as the most suited stuff for cement replacing and for the synthesis of base activated cement/ inorganic polymer binder [ 73 ] .

Harmonizing to Mehta [ 74 ] about 70 % of ash available is suited for synthesising cementitious systems. If the available fly ash and GGBS are utilized to the full and efficaciously, it is possible to run into the projected cement demand without increasing the current installed capacity of cement workss [ 75 ] . For the present probe GGBS was obtained from JSW steel works, Bellary, Karnataka. The physical and chemical belongingss of GGBS are given in Table 3.2.

3.2.3 Coarse Aggregate

It is good known that the strength of OPC is dependent about on the strength of the binder and the interfacial bond between the binder and the sum. Therefore the usage of stronger sums does non better the strength of the normal concrete significantly. However, in GPC, both the binder strength and the interfacial bond strength may either attack or transcend the strength of the sums. When the binder and interfacial bond strength exceeds that of the strength of the sums, the usage of stronger sums can take to a considerable betterment in the strength of the concrete. Sums play a critical function in the belongingss of both fresh and hardened GPC since sums ( both mulct and coarse ) occupy about 75 to 80 per centum of the entire concrete volume.

For usage as coarse sum, equi-dimensional atoms obtained by oppressing a dense limestone or irruptive type pyrogenic stone ( such as granite, basalt, syenite, diorite, and diabase ) , are normally satisfactory. There is some contention sing the pick of maximal size of sum ( MSA ) . However, available information shows that larger than 25 millimeter MSA by and large impairs the strength and impermeableness of concrete. Hence 10 millimeter to 20 millimeters MSA may be considered optimal for GPC, which is similar to that of OPC.

Crushed basalt stone french friess were used in the present probe. The maximal size of the sum was 20 millimeter. The sample of sum confirms to IS:383-1970 [ 77 ] . The physical belongingss and sieve analyses of three types of sums are as given in Table 3.3.

Table 3.2: Physical and Chemical belongingss of Ground granulated blast furnace scoria

Properties	Experimentalvalues	Valuess as per IS:12089-1987 [ 76 ]
Physical Properties
Specific gravitation	2.86
Bulk denseness, kg/m3	1230
Delicacies, m2/kg	400	275 Min.
Soundness Le-Chatelier enlargement ( millimeter )	1.6	10 Max.
Puting clip ( proceedingss ) Initial Concluding	170 308	Not less than OPC
Compressive strength MPa ) 7 twenty-four hours 28 twenty-four hours	26.4 42.3	12 Min. 32.5 Min.
Chemical Properties
Oxide composing ( % by mass )
Silica ( SiO2)	43.4	70 min.
Ferric Oxide ( Fe2Oxygen3)	1.3
Aluminium Oxide ( Al2Oxygen3)	12.5
Calcium Oxide ( CaO )	40.3	45
Magnesium Oxide ( MgO )	1.5	5.5 Max.
Sulphide sulfur	1.93	2 Max.
Phosphorous	0.6	–
Alkali Oxide ( Al2Oxygen3)	0.15	1.5 soap.
Loss of ignition ( LOI )	1.80	12 soap.

Table 3.3 Properties of coarse sums

Physical belongings	Experimental values
Specific gravitation	2.70
Bulk denseness ( kg/m3)	1650
Fineness modulus	5.90
Aggregate oppressing value ( % )	15.78
Aggregate Impact Value ( % )	15.41
Water soaking up ( % )	0.50
Fineness Modulus	6.8
Beginning	Crushed granite rock

3.3.4 Fine sum

The scaling and atom form of the all right sum are important factors in the production of GPC. The atom form and texture affect the commixture H2O demands and compressive strength. By and large the coarser type of sand is used because the finer one will absorb more H2O from the concrete and another major ground is that GPC comprises of big measure of finer atoms in the signifier of fly ash and land granulated blast furnace scoria etc.

Locally available sand quarried from Krishna River was used. The sand used conforms to rating zone II of Table 4 of IS: 383-1970 [ 77 ] . The physical belongingss of all right sums used in the probes are presented in Table 3.4

Table 3.4 Properties of all right sums

Physical belongings	Experimental values
Specific gravitation	2.61
Bulk denseness kg/m3	1670
Fineness modulus	2.60
Silt content	0.6 %
Rating Zone	Two
Water soaking up	1.20 %
Beginning	River bed

3.3.5 Cement

Commercially available ordinary Portland cement of 43 class ( Ultratech cement ) conforming to the relevant Indian criterion codification IS:8112-1989 [ 78 ] was used throughout the probe. The physical and chemical features of cement were determined as per IS: 4031-1988 ( portion 3 to portion 6 ) [ 79, 80, 81, 82 ] are given in the Table 3.5. The

3.3.6 Water

Water used for commixture and hardening should be free from hurtful stuffs as per clause 4.3 of Is:456-2000 [ 83 ] . Drinkable H2O ( pH value between 7 and 7.5 ) is by and large considered satisfactory for blending and hardening of concrete. The clause farther requires that the pH value should non be less than 6. Drinkable tap H2O available in the research lab was used in the present survey.

3.3.7 Alkaline Liquid

The alkaline liquid used for the experimental probe is a combination of Na hydrated oxide and Na silicate solution. It is seen that the geopolymers with Na hydroxide solution exhibit better zeolitic belongingss than K hydrated oxide activated geopolymers. It has been confirmed that add-on of Na silicate solution to sodium hydrated oxide enhanced the reaction rate between beginning stuff and the alkalic solution. The Na hydrated oxide solids ( pellet signifier ) and sodium silicate solution were obtained from Amar Chemicals Agency, Bangalore.

Table 3.5: Physical and Chemical belongingss of cement

Properties	Experimental values	Valuess as per IS: 8112-1989 [ 78 ]
Physical Properties
Specific gravitation	3.12	3.15
Bulk denseness, g/cc	1865
Delicacies, m2/kg	340	225 Min.
Normal Consistency ( % )	30
Puting clip ( proceedingss ) Initial Concluding	180 255	30 Min. 600 Max.
Soundness Le-Chatelier enlargement ( millimeter )	2	10 Max.
Compressive strength ( MPa ) 3 yearss 7 yearss 28 yearss	38.40 46.60 60.20	23 Min. 33 Min. 43 Min.
Chemical Properties
	0.86	0.66 Min. 1.02 Max.
Aluminum2Oxygen3/ Fe2Oxygen3	1.17	0.66 Min.
Insoluble Residue ( % by mass )	2.32	5.00 Max.
Magnesia ( % by mass )	0.93	6.00 Max.
Sulphuric Anhydride ( % by mass )	1.83	3.00 Max.
Entire loss on Ignition ( % by mass )	1.40	4.00 Max.
Entire chlorides ( % by mass )	0.006	0.10 Max.

3.3.8 Sodium hydrated oxide

The Na hydrated oxides are available in solid province by agencies of pellets and flakes. It is called as acerb sodium carbonate, which is hygroscopic and readily absorbs CO₂from the air and should be stored in an air tight container. It is soluble in H2O and is extremely exothermal when dissolved in H2O. The cost of the Na hydrated oxide is chiefly varied harmonizing to the pureness of the substance. The geopolymer concrete is homogenous stuff and its chief procedure is to trip Na silicate, so it is recommended to utilize sodium hydrated oxide with marginally lower cost. The physical belongingss of Na hydrated oxide solution are presented in Table 3.6.

Table 3.6: Properties of Na hydrated oxide solution

Appearance	Liquid ( gel )
Coloring material	Light yellow liquid
Molecular weight	185.24
Specific gravitation	1.16
Melting point	318 °C
Boiling point	1390 °C
Assay	97 % Min
Storage	Air tight container

3.3.9 Sodium silicate

By and large sodium silicate is known as H2O glass or liquid glass, available in liquid ( gel ) signifier. It is used as natural stuff in detergents, mush and paper, ceramic industry, inactive fire protection, fabric, cars and industry of Ti di oxide. In the present probe Na silicate 2.0 ( ratio between Na₂O to SiO₂) is used. The physical belongingss of Na silicate solution are presented in Table 3.7.

Table 3.7: Properties of Na silicate solution

Chemical expression	Sodium2O.xSiO2
Sodium2Oxygen	15.80 %
SiO2	31.58 %
Water	52.62 %
Appearance	Liquid ( gel )
Coloring material	Light yellow liquid
Molecular weight	185.24
Specific gravitation	1.57

3.3.10 degree Celsiusshemical alloies

In order to better the workability of fresh concrete, high-range water-reducing naphthalene based ace plasticizer Conplast SP-430 purchased from Fosroc Chemicals, was added to the mixture. The belongingss of ace plasticiser are presented in Table 3.8.

Naphthalene based superplasticizers are sold as a brown liquid, with the entire sum of solid atoms by and large between 40 and 42 % . They are besides available in solid signifier as a chocolate-brown pulverization. Both the liquid and solid signifier naphthalene superplasticizers are available as Na or Ca salts, but more frequently as Na salt. Naphthalene superplasticizers have higher solids content, so they are most cost effectual to obtain a certain grade of workability. These are less expensive. In the present probes, superplasticizer was assorted with alkalic solution and was so added to the dry stuffs. The dose of superplasticizer was adjusted to accomplish suited workability.

Table 3.8: Properties of superplasticizer

Trade name	Conplast SP-430 ( FOSROC, Mumbai )
Density	1206 kg/m3
Base chemical	SNFC
Specific gravitation	1.205
pH	8.03
Appearance	Brown liquid
Solid content	40 %
Mention specifications	IS:9103-1999 [ 84 ]

3.3.11 Reinforcing Steel

The steel used for the beams in the present work was with Fe–415 corroborating to IS:1786-1985 [ 85 ] . The rebars were tested in a cosmopolitan proving machine ( UTM ) of 1000 kN capacity as shown in Fig. 3.1. The steel bars were cut into 1000 millimeter length and gripped in the jaws of the machine. To mensurate axial supplanting an extensometer was used. The stress-strain curve, modulus of snap and output emphasis at 0.2 % cogent evidence emphasis were determined.

3.4 Design of concrete mixes

The chief aim of a concrete mix design is to choose the optimal proportion of the assorted ingredients of concrete. Such proportion shall give concrete possessing the needed malleability when viridity and fulfilling the needed strength and lastingness demands in the hard-boiled province [ 44 ] . For the present probe three types of mixes were designed, they are designated with the specific designation as given in Table 3.9.

.Table 3.9 Terminology used for design mix

Type of Mix	Designation	Beginning Materials used
Geopolymer concrete	GPC1	Fly ash ( 100 % ) , CA, FA, Alkaline solutions
Geopolymer concrete	GPC2	Fly ash ( 60 % ) , GGBS ( 40 % ) , CA, FA, Alkaline solutions
Conventional concrete	OPC	Cement, CA, FA, Water

3.4.1 Design of geopolymer concrete mix

Geopolymer concrete is emerging field in concrete engineering, since there are no available criterions or codifications for pattern of GPC mixes, the current mix design method is based on the process given by Rangan, B.V [ 82 ] . The GPC mix comprising of coarse and all right sums was taken as 77 % of full mass. The denseness of geopolymer concrete is taken similar to that of OPC as 2400 kg/m³[ 86 ] . The inside informations of mix design and its proportions for different classs of GPC, GPC1 with changing molar concentrations and alkalic ratios are presented in Appendix A.

3.4.2 Design of conventional concrete mix

To compare the consequences of geopolymer concrete it was planned to project the mixes with different classs of concrete as per IS:10262-2009 [ 87 ] . The inside informations of design mix and its proportions are presented in Appendix B.

3.5Drumhead

In this chapter physical, chemical, mineralogical and morphological word picture was carried out on the stuffs proposed to be used in the probe. The consequences show that the proposed beginning stuffs to be used as binder constituents are suited for doing geopolymer complexs. Consequences of trial on different sums besides indicate their suitableness for usage in the survey. The fly ash corresponds to category F, GGBS and other fringy stuffs possessing desirable features will be used in concurrence with all right sum to deduce desirable public presentation of the ambient and heat cured geopolymer complexs. Therefore the stuff word picture is an of import stage of the proposed experimental probe.

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