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Full Paper Proc. of Int. Conf. on Advances in Civil Engineering 2012

Effect of Corrosion Inhibitor on The Strength and Durability Properties of Quarry Dust Concrete Dr.M.Devi, Professor in Civil Engineering, Paavai Engineering College (Affiliated to Anna University Chennai), Namakkal-637018, Tamilnadu, India. Email: devimcivil@gmail.com Abstract— The demand for natural sand in the construction industry has consequently increased which has resulted in the reduction of sources and an increase in price. In such a situation quarry dust can be an economical alternative to the river sand. In this paper an experimental study has been done to investigate the use of quarry dust as fine aggregate in concrete. Corrosion of steel reinforcement is one of the main durability problem which the reinforced concrete structures face world wide. The objective of this work is to study the strength and corrosion resisting properties of concrete containing quarry dust as fine aggregate along with an organic inhibitor namely Triethylamine at the dosage of 1%, 2%, 3% and 4% by weight of cement. Strength tests, water absorption test and the durability tests were conducted and the results were compared with the natural sand concrete. The resistance to corrosion is evaluated based on the performance of the concrete for the penetration of chloride ions by means of impressed voltage method and weight loss measurement. From the results obtained it is found that replacement of sand by quarry dust increases the strength of the concrete, with addition of inhibitor it offers very good resistance against chemical attack and increases corrosion resistance in addition to the over all properties of concrete. Index Terms— Concrete, quarrydust, superplasticizer, inhibitor, chloride ingress, corrosion resistance

I. INTRODUCTION

than anticipated due to the corrosion of reinforcing steel [13] and thus need replacement, rehabilitation or strengthening [14,15]. Corrosion can be prevented by chemical method by using certain corrosion inhibiting chemical and coating to reinforcement. According to NACE [National Association of Corrosion Engineers] inhibitors are substances which when added to an environment; decrease the rate of attack on a metal [16]. Corrosion inhibitors function by forming a passive layer around the reinforcing steel and prevent out side agents and reduce the corrosion current [17,18]. Corrosion inhibitors are becoming an accepted method of improving durability of reinforced concrete in chloride laden environments [19,20].This paper deals with the experimental study to investigate the effect of Triethylamine as inhibitor in concrete containing quarry dust as fine aggregate in resisting corrosion. II. MATERIALS Ordinary Portland Cement (43 Grade) was used throughout the investigation. River sand, confirmed to grading zone – II as per table 4 of IS 383-1970 has been used as fine aggregate for control specimen. Locally available well-graded quarry dust, conforming to Zone-II having specific gravity 2.68 and fineness modulus 2.70 was used as fine aggregate. Natural granite aggregate having density of 2700kg/m3, specific gravity 2.7and fineness modulus 4.33 was used as coarse aggregate. High yield strength deformed bars of diameter 16mm was used for pullout and corrosion tests. To increase the workability of quarry dust concrete commercially available super plasticizer ROFF 320 has been used. The inhibitors used was Triethylamine at 1%, 2%, 3% and 4% by weight of cement. To attain strength of 20 N/mm2 a mix proportion was designed based on IS 10262-1982 and SP23:1982(21). The mixture was 1:1.517:3.38 with water cement ratio 0.45.

Concrete containing quarry dust as fine aggregate is promising greater strength, lower permeability and greater density which enable it to provide better resistance to freeze/ thaw cycles and durability in adverse environment [1,2]. Hundred percent replacement of quarry dust in concrete is possible with proper treatment of quarry dust before utilization [3,4]. The compressive strength of quarry dust concrete can be improved with admixtures [5] and also super plasticizers can be used to improve the workability of quarry dust replaced concrete [6]. Concrete produced using quarry fines shows A. Properties of the Inhibitor: improvement in higher flexural strength, abrasion resistance, Triethylamine is an organic chemical compound, obtained and unit weight which are very important for reducing from the reaction between ammonia and ethylene oxide. The corrosion or leaching [7]. Self-compacting concrete and also properties of the inhibitor are as follows: be produced using quarry dust [8].Durability of concrete may Appearance : colourless liquid with a strong amine odour be defined as the ability of concrete to resist weathering Formula : C6H15N action, chemical attack and abrasion while maintaining its Boiling point : 89.4 C desired engineering properties [9,10]. Corrosion of reinforcing Molecular weight : 101.19 steel is a major problem facing the concrete infrastructures Specific gravity : 0.73 [11,12]. Many structures in adverseenvironments have Melting point : 114.75 C experienced unacceptable loss in serviceability of safety earlier 131 © 2012 ACEE DOI: 02.AETACE.2012.3.10

Full Paper Proc. of Int. Conf. on Advances in Civil Engineering 2012 III. EXPERIMENTAL PROGRAM

G. Acceleration Corrosion Process Specimens were subjected to the acceleration corrosion process. 3% sodium chloride salt mixed with water which represents typical sea water was used as electrolyte solution using a power pack; the current was supplied to the specimens. The test specimens were subjected to a constant voltage of 6 volts from the D.C power pack. The reinforcement in specimens was connected to positive terminals of the power pack. Stainless steel plates connected to the negative terminal of the power pack was used as cathode to gather irons ions diffusing from embedded steel [anodic area]. The galvanostat cell was created in FRP [fibre reinforced plastics] tank. After the process of accelerated corrosion was over the entire specimen were disconnected and removed from FRP tank.

The following experiments were conducted to thoroughly investigate the strength, micro structural properties and corrosion resistance characteristics of the quarry dust replaced concrete with addition of Triethylamine at 1%, 2%, 3% and 4% by weight of cement. A. Strength Test Concrete cubes of size 150 X 150 X 150mm, beams of size 500 X 100 X 100 mm cylinders of size 150mm diameter and 300 mm long were cast with and with out Triethylamine for compressive, flexural and split tensile strength. After 24 hours the specimens were demoulded and subjected to water curing. After 3, 7and 28 days the specimens were tested as per IS: 516 – 1964. Cylinders of size150mm diameter and 300 mm long with rods of 70cm length kept at the centre were used for determination of bond strength.

H. Corrosion by Weight Loss Rod Method The steel rod of size 16 mm diameter and 150 mm long is immersed in the pickling solution [Hydrochloric acid +water in equal parts] for 15 minutes to remove the initial rust. The initial weight [W1] of the rod was measured At the end of polarization test the cylinder specimen were broken open and weight-loss rods were retrieved. After cleaning with water, the rod was air dried and its final weight [W2] was measured. From the initial and final weight, the corrosion rate was calculated. The corrosion rate is calculated using the following formula: Corrosion rate in mmpy = 87.6 [W1 – W2] / DAT Where, W1 = Initial weight in milligrams W2 = Final weight in milligrams D = Density of steel gm/ cm3 A = Area of the specimen in cm2 T = Test period in hours.

B. Micro Structural Properties Water absorption of hardened concrete specimens was calculated based on ASTM C642-81.After 28 days curing the specimen were taken out and dried in an oven at 105°C for 24 hours. The dried specimens were cooled to room temperature [25°C], weighed accurately and noted as dry weight. Dry specimens were immersed in water and the weight of the specimens at predetermined intervals was taken after wiping the surface with dry cloth. This process was continued up to constant weight is obtained in two successive observations. percentage of permeable voids and bulk density were determined as per ASTM C 642-97. C. Percentage of Water Absorption: Percentage of water absorption = {[B-A] / [A]}x10 Where A =weight of the specimen after oven dry [gms]. B= weight of the specimen after 48 hrs immersion in water [gms].

I. Specimen Identification The various specimen cast are shown in Table I.

D. Percentage of Permeability Percentage of Permeability = {[C-A] / [C-D]}x100 Where C =weight, after 5 hrs heated [gms]. D= submerged weight in water [gms].

TABLE I. SPECIMEN IDENTIFICATION

E. Bulk Density Bulk density of the specimen [γD] γD = weight / volume of specimen [gms/cm3] IV. RESULTS AND DISCUSSION

F. Durability Test To assess the corrosion protection efficiency under accelerated test conditions, concrete cylinders of size 75mm diameter and 150mm length, with centrally placed steel rod of 16mm diameter were cast. The steel rod is placed in such a way that a constant cover is maintained all round [i.e.29.5mm].

A. Strength Tests The strength test results are shown in table 2.

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Full Paper Proc. of Int. Conf. on Advances in Civil Engineering 2012 TABLE II. R ESULTS OF STRENGTH TESTS AFTER 28 DAYS C URING

Fig. 4. Bond strength after 28 days curing

A. Discussion on Conventional Concrete and Quarry Dust Replaced Concrete: The compressive, split tensile, and bond strength results at 28 days are given in Table 2. The strength test results of quarry dust replaced concrete specimens were compared with the conventional concrete specimens. When comparing the results of C1and C2 from Table 2, it is obvious that quarry dust replaced concrete specimens [MIX C2] have shown improvement in the above strength tests when compared to the control specimen made of river sand [MIX C1]. There was 8.75% increase in compressive strength, 2.5% increase in split tensile strength , 1.68% increase in flexural strength and 5.68% increase in bond strength. From these data it is obvious that concrete having quarry dust as fine aggregate along with super plasticizer does not show any adverse effects on the strength properties.

Fig. 1. Compressive strength after 28 days curing

B. Discussion on Quarry Dust Replaced Concrete With And Without Inhibitor: The strength test results for concrete containing quarry dust as fine aggregate along with Triethylamine at 1%, 2%, 3% and 4% are shown in figures 1, 2, 3 and 4. Addition Triethylamine shows maximum improvement in compressive strength at 2% dosage. For 3% and 4% addition of inhibitor there was a slight reduction in strength due to retardation of C3S hydration. Over dosing of corrosion inhibitors resulted in acceleration in setting time which lead to a reduction in ultimate strength of concrete. Considering the compressive strength [fig.1], Mix P2 shows 10.96% increase in strength which is the maximum when compared to Mix C2.But MIX P4 has shown 22.46% decrease in compressive strength when compared to control specimen MIX C2. From fig.2 it is observed that quarry dust concrete specimens along with 2% inhibitor showed the maximum increase in split tensile strength by 8.75%. However the strength is reducing gradually for 3% and 4% addition of inhibitor. MIX P4 shows 21% reduction when compared to control specimen.All quarry dust replaced specimens with addition of inhibitor have shown slight increase in flexural strength when compared to control specimen C2. [fig.3]. Especially the addition of 2% of the

Fig. 2. Split Tensile Strength after 28 days curing

Fig. 3. Flexural strength after 28 days curing

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Full Paper Proc. of Int. Conf. on Advances in Civil Engineering 2012 inhibitor shows the maximum improvement of 1.7%. From fig .4 it is found that bond strength of quarry dust replaced concrete specimens are more than the control specimen but the strength of MIX P4 is reduced by 24.5%. From the results of the mechanical strength tests it could be concluded that the strength of the specimens with 4% of inhibitor is less than the control specimen and also below the permissible limits. Hence, micro structural properties and the durability studies are not taken for the MIX P4.

comparison is shown in fig. 5.The percentage of permeable voids is also reduced with the increase of percentage of inhibitor in quarry dust concrete. Fig 6 shows the reduction of permeable voids in quarry dust concrete with the addition of inhibitor. Figure7 indicates the improvement of bulk density in quarry dust concrete along with inhibitor when compared with control specimen. The results of micro structural properties show that among all the percentages of inhibitor added, 2% of Triethylamine was found to be the optimum percentage.

V. MICRO STRUCTURAL PROPERTIES VI. DURABITY TESTS

Figures 5 to 7 demonstrate the percentage of water absorption, percentage of voids and bulk density of the control specimens and inhibitor added specimens.

A. Impressed Voltage Test The specimens were tested by impressed voltage technique and the time taken for initiation of corrosion in the specimen is shown in fig.8.

Fig. 5. Water absorption

Fig. 8. Corrosion initiation time

The specimens were tested by impressed voltage technique and the time taken for initiation of corrosion in the specimen is shown in Table 6. Test results have shown that the ordinary concrete specimen C1 started to corrode after 160 hrs. Specimen with 100% replacement of river sand with quarry dust MIX C2, started at 158 hrs. Quarry dust replaced concrete specimen with addition of 1% inhibitor MIX P1 started after 208 hrs. The specimen with 2% inhibitor MIX P2, started after 268 hrs and MIX P3 with 3% of inhibitor, started to corrode after 264 hours. The above results clearly indicated that corrosion resistance increased with increase of percentage of inhibitor up to 2%. This could be clearly seen in fig.8.

Fig.6. Percentage of permeable voids

B. Weight Loss Measurements Fig 9 shows the reduction of corrosion rate by the addition of inhibitor. Corrosion rate from the weight â&#x20AC;&#x201C; loss measurements clearly indicates that the rate of corrosion decreases with the increase of percentage of inhibitor up to 2% and further addition shows a slight increase when compared to MIX P2.

Fig. 7. Bulk density

In accordance with fig.5, the water absorption of quarry dust replaced concrete after saturation was found to be less when compared with ordinary concrete specimens. The

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Full Paper Proc. of Int. Conf. on Advances in Civil Engineering 2012 [3] Ilangovan, R. and Nagamani, K. “Application of quarry Rockdust as fine aggregate in concrete construction”, National Journal on construction Management: NICMR. Pune, pp. 5-13, 2006. [4] Ilangovan, R. and Nagamani, K. “Studies on Strength and Behavior of Concrete by using Quarry Dust as Fine Aggregate”, CE and CR Journal, New Delhi, pp. 40-42, 2006. [5] Prachoom Khamput, E “ A study of compressive strength of concrete using quarry dust as fine aggregate and mixing with admixture type E”, Rajamangla University of Technology Thanyaburi, Pathumthani, Thailand,2005. [6] Nagaraj, T.S. and Zahida Banu, “Efficient Utilization of rock dust and pebbles as Aggregates in Portland Cement Concrete”, The Indian Concrete Journal. pp. 53-56, 1996. [7] Professor David Manning and Dr. Jonathan Vetterlein. “Explotation and use of quarry fines” ReportNo: 087/MIST2/ DACM/01. MST project reference: MA/2/4/2003. [8] Raman, S.N., Md Safiuddin and Zain, M.F.M. “Non – Destructive of flowing concretes incorporating quarry waste”, Asian journal of Civil Engineering (Building and Housing) Vol.8, No.6, pp. 597 -614,2007. [9] Shetty, M.S. “Concrete Technology”, Theory and practice, 2008. [10] “Concrete durability”, Canadian strategic highway research programme, C[11] Browne, R.D. Geoghegan M.P. and Baker, A.F. Crane, A.P. “Corrosion of reinforcement in concrete construction”, London,UK. Transportation association of Canada, p. 193, 1983. [12] Ha-Won Song, and Velu Saraswathy “Corrosion monitoring of reinforced Concrete structures – A review”, International journal of electrochemical science, Vol. 2, pp. 20-28, 2007. [13] A.Castel,R. Francois and G.Arligue, “Mechanical behavior of corroded reinforced concrete beams damaged by reinforcement steel corrosion” .Material structural Journal.33 [2330 [20000 539-544.– Part1 [14] Videm “Corrosion of Reinforcement in concrete. Monitoring, prevention and Rehabilitation”. EFC No: 25. London, pp. 104-121, 1998. [15] Vedalakshmi, R. and Rengasamy, N.S. Quality assurance tests for corrosion resistance of steel reinforcement. The Indian concrete journal, 2000. [16] Michael Brown, C. Richard Weyers, E. and Michael Sprinkel, M. “Solution tests of corrosion inhibiting admixtures for reinforced concrete”, ACI Material journal, 2002 [17] Violetta Munteanu, F. and Frederick Kinney, D. “Corrosion Inhibition Properties of a Complex Inhibitor - Mechanism of Inhibition”, CANMET, pp. 255-269, 2000. [18] Michael Brown, C., Richard Weyers, E. and Michael Sprinkel, M. “Effect of corrosion – Inhibiting admixtures on material properties of concrete”, ACI Material journal, Vol.98. No.3, 2001. [19] Ping Gu, Elliott, S., Hristova, R., Beaudoin, J.J., Brousseau, R. and Baldock, B. “Study of corrosion inhibitor performance in chloride contaminated concrete by electrochemical impedence spectroscopy”, ACI Material journal, Vol. 94, No. 5, 1997. [20] Paul Vrkljan, Alla Furman and Christophe Chandler “Measuring the effectiveness of migrating corrosion inhibitors (mcis) by electrochemical techniques”, Cortec Corporation, 4119, White Bear Parkway, 1997.

Fig. 9. Corrosion rate with addition of inhibitors

It is also evident from the corrosion test results that the corrosion resistance of quarry dust concrete is higher than the conventional concrete in all the cases. CONCLUSION From the experimental studies the following conclusions were drawn: The concrete containing well graded quarry dust as fine aggregate along with plasticizer can be effectively utilized in the construction industry. The strength and corrosion resistive properties of quarry dust concrete are slightly higher than the conventional concrete. Among the various percentages (1%, 2%, 3% and 4%) of Triethylamine added, the quarry dust replaced concrete with 2% addition of inhibitor shows maximum improvement in the compressive strength, split tensile strength, flexural strength, and bond strength when compared to the control specimen.  By adding corrosion inhibitor permeability & water absorption properties were considerably reduced. Addition of the organic inhibitors to quarry dust replaced concrete, offered very good resistance against chemical attack and increases corrosion resistance by forming thin oxide layer to prevent outside agents and shielding the anodic sites.  Considering strength as well as durability criteria, the optimum percentage of Triethylamine to be added in concrete containing quarry dust as fine aggregate is 2% .for delaying corrosion and to increase the strength and other durability characteristics. To conclude, concrete having quarry dust as fine aggregate along with 2% of Triethylamine can be effectively used in reinforced concrete structures for delaying corrosion and to increase other strength and durability characteristics. REFERENCES [1]

Sahu, A.K., Sunil Kumar and Sachan, A.K. “Quarry stone waste as fine aggregate for concrete”, The Indian concrete journal. pp. 845-848. 2003. [2] Ilangovan, R., Mahendrana, N. and Nagamani, K. “Strength and durability properties of concrete containing quarry rock dust as fine aggregate”, ARPN Journal of Engineering and Applied Science, Vol;.3, No.5, pp 20-26,2008.

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