COMPARATIVE STUDY OF TWO COMMERCIALLY AVAILABLE SUPERPLASTICIZERS ON THE PROPERTIES OF CONCRETE

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1 COMPARATIVE STUDY OF TWO COMMERCIALLY AVAILABLE SUPERPLASTICIZERS ON THE PROPERTIES OF CONCRETE Saeed Ahmed*, Engineering University Taxila, Paksitan Attaullah Shah, Allama Iqbal Open University, Pakistan Ajmal Saleemi, Engineering University Taxila, Paksitan 32nd Conference on OUR WORLD IN CONCRETE & STRUCTURES: August 27, Singapore Article Online Id: The online version of this article can be found at: This article is brought to you with the support of Singapore Institute All Rights reserved for CI Premier PTE LTD You are not Allowed to re distribute or re sale the article in any format without written approval of CI Premier PTE LTD Visit Our Website for more information

2 32 nd Conference on OUR WORLD IN CONCRETE & STRUCTURES: August 27, Singapore COMPARATIVE STUDY OF TWO COMMERCIALLY AVAILABLE SUPERPLASTICIZERS ON THE PROPERTIES OF CONCRETE Saeed Ahmed*, Engineering University Taxila, Paksitan Attaullah Shah, Allama Iqbal Open University, Pakistan Ajmal Saleemi, Engineering University Taxila, Paksitan Abstract High range water reducers (super plasticizers) are extensively used in concrete industry to mainly develop high performance concrete and to improve different properties of concrete in fresh and hardened state. In this work, two commercially available super plasticizers of polycarboxylic base have been tested and compared to study their effects on the concrete properties such as workability, compressive strength, and water reduction, tensile strength. Four series of different concrete mixes (1:2:4, 1:1:2, 1:1.25:2.5, 1:1.5:3) were tested for three values of.3,.35,.4 at constant dosage of % by weight of cement The results demonstrate that super plasticizers have improved the properties of concrete in fresh and hardened states and these can be used in the traditional construction as well with little or no increase in cost as the additional cost of admixtures ca be saved by reducing the cement content, construction period and other indirect costs. Keywords: Expansion, Alkali, Aggregate, Reaction, corrosion, ASR 1. Introduction: admixtures are widely used in the construction industry across the world, to improve its different properties both in fresh and hardened states. Superplasticisers are chemical admixtures also referred to as high range water reducers, which can reduce the water cement n by 25%. The superplasticisers are classified under four major groups as follows; Sulfonated Naphthalene Formaldehyde Condensate ( SNF) Sulfonated Melalmine Formaldehyde Condensate (SMF) Modofoed Linosulfonates ( MLS) Others including polyarcylates, polystyrene sulfonates, polymers etc. These superplsicisers affect the various properties of concrete due to following facts 1 ; Reduction in interfacial tension of the concrete ingredients.

3 Multi-layered absorption of the organic molecules. Protective adherent sheath layer of water molecules. Retarding effect of cement due prolonged hydn. Change in morphology of hydrated cement. In this research two types of superpalsticisers (SP) of Carboxylic Ether based with brand names Gelenium-51 (made by Degussa) and crete ( Made by Sika chemicals) have been used to study and compare their effects on compressive strength of concrete, tensile strength of concrete, modulus of rapture, water reduction, saving of cement. Overall the improvement in various properties of concrete in fresh and hardened from is more pronounced with, but due its very high cost, it cannot be used in ordinary concrete structures and is recommended for High Performance (HPC), where very early strength and high compressive strength of concrete is desired. The viscocrete of Sika on the other hand provides a relatively cheaper and moderate solution for medium strength concrete. 2. Objective of Research: The research objective was to compare the two types of commercially available SP widely used in local construction industry of Pakistan for their effect on the properties of concrete. 3. Material: Cement: Ordinary Portland Cement (OPC) of Type-I was used and the following properties were tested: Setting Time: (Vicat Apparatus ASTM-C191) Initial setting time 5 minutes and final stetting time:5 hour & 5 minutes(35 minutes). Standard Consistency (ASTM-C187-83): 33.8% Soundness test determined by Le Chatleir apparatus: 3.5 mm Specific gravity of cement (ASTM-C188): 3.6 Fine aggregates: fulfilling ASTM-136 gradation requirements and collected from Lawrencepur river source Pakistan. The bulk specific gravity of the fine aggregates was 2.75 and 24 hours soaking as 1.46% Coarse aggregates: Lime stone aggregates collected from Margalla Hills source near Islamabad- Pakistan and ¾ in down sizes. High Range water Reducers: -51( degussa made) conforming to ASTM C494-Type A and F, is carboxylic ether group with long lateral chain. crete-21 is a high range water reducer (Sika made) conforming to ASTM C494- Type A and F and belong Polycarboxlate polymer group. Both the SP were of the weight of cement. Three mix designs of concrete with nominal s of cement, sand and coarse aggregates as 1:1:2, 1:1.25:2.5 and 1:1.5:3 were used. 4. Testing of material and Experiment: The following tests were administrated on concrete; Work ability test ( Slump Cone test) Compressive Strength ( 45 Cubes of 6inx6inx6in were tested) Splitting tensile tests (36 Nos 6inx12in cylinders were tested.) Flexural strength test - Modulus of rapture ( 36 Nos 4inx4inx2in beams were tested) 5. Observations and Conclusions: 5.1: Effect of Superplasticisers on workability compressive strength: Both SP have improved the compressive strength of concrete, however the increase is more pronounced by -51. The workability of concrete increased but in case of, it

4 has collapsed, making it good SP for self compacting concrete. The comparison has been shown in Table1 to Table7 and Fig1 to Fig 7 for different mixes of concrete. Table 1: Effect of Superplasticiser on the compressive strength of concrete for 1:1:2 mix and w/c =4% :1: %() %() Collapse Fig:1 Effect of Superplasticisers on the compressive strength of for 1:1:2 concrete mix and w/c : Table 2: Effect of Superplasticiser on the compressive strength of concrete for 1:1:2 mix and = 35% :1: %() %() Collapse

5 Fig2: Effect of Superplasticisers on the compressive strength of for 1:1:2 concrete mix and w/c : Table 3: Effect of Superplasticiser on the compressive strength of concrete for 1:1:2 mix and = 3% :1: %() %() Fig3: Effect of Superplasticisers on the compressive strength of for 1:1:2 concrete mix and w/c :

6 Table 4: Effect of Superplasticiser on the compressive strength of concrete for 1:1.5:2.5mix and w/c =4% :15: %() %() Fig:4 Effect of Superplasticisers on the compressive strength of for 1:1.5:2.5 concrete mix and w/c : Table 5: Effect of Superplasticiser on the compressive strength of concrete for 1:1.5:2.5 mix and w/c =35% :1.5: %() %()

7 Fig:5 Effect of Superplasticisers on the compressive strength of for 1.1.5:2.5 concrete mix and w/c : Table6: Effect of Superplasticiser on the compressive strength of concrete for 1:1.5:2.5 mix and = 3% :15: %() %() Fig6: Effect of Superplasticisers on the compressive strength of for 1:1.5:2.5 concrete mix and w/c :

8 Table 7: Effect of Superplasticiser on the compressive strength of concrete for 1:1.5:3 mix and w/c =4% :1.5: %() %() Fig:7 Effect of Superplasticisers on the compressive strength of for 1:1.5:3 concrete mix and w/c :.4 ( psi) : Effect of Superplasticisers on tensile strength (Split Cylinder test) : The tensile strength of concrete was investigated at 35% water cement and the dosage of SP was used as.7% of cement weight as before. Both the SP have improved the splitting tensile strength of concrete, but the effect of is relatively more. The results are shown in table 8 Table8: Effect of Superplasticisers on the Splitting tensile strength of Slump Cylinder tensile strength No SP No SP 1:1: :1.5: Collapse :1.5: Effect on Modulus of rapture( Flexural Strength) : The modulus of rapture measured with beam test, has been increased with both the SP, but the increase is more in case of. The results are shown in Table9.

9 Table9: Effect of Superplasticisers on the Flexural strength of ( Modulus of rapture) Slump Flexural strength No SP No SP 1:1: Collapse :1.5: :1.5: Water reduction effect of Superplasticisers: The dosage of superplasticiser was changed to maintain a constant slump of 25. The strength was as result increased with the increased and the water cement decreased. Water reduction upto 22 % led to increase of compressive strength from 49 psi to 62 psi for viscocrete and 25% reduction of water cement increased the compressive from 521 psi to 671 psi for. The results are shown in Table 1. SP dosage % water reduction Slump 28 Compressive Strength crete crete crete crete crete References: 1. A.Borosoi. S.Collepradi,L.Coppola, R.Troli Effect of Superplasticisers type on performance of High Volume fly ash concrete 2. P.Kumar Mehta Reducing Environmental Impact of International A.M.Neville, Use of superplasticisers and its effects Habil, Jansuzszwabowski Rhelogical properties of fresh cement mortars containing new genen superplasticisers-may CBI Repport/Report2:95 Effect of second genen superplasticisers on concrete properties Feb Saeed Ahmad, A. Shah. K.Ali Effect of water reducing concrete admixtures on the properties of concrete: 29 th Conference Our world in & Structures-Aug 24