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Chemical Industry & Chemical Engineering Quarterly www.ache.org.rs/CICEQ Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016) CI&CEQ

MUHAMMAD IMRAN AHMAD1 SUSTAINABLE PRODUCTION OF BLENDED MUHAMMAD SAJJAD1 2 IN PAKISTAN THROUGH ADDITION IRFAN AHMED KHAN OF NATURAL POZZOLANA AMINA DURRANI2 1 ALI AHMED DURRANI Article Highlights 1 SAEED GUL • Ordinary is partially substituted with rhyolite to reduce cost ASMAT ULLAH1 • Blended employing rhyolite are demonstrated to possess satisfactory com- pressive strength 1 Department of Chemical • Inter-grinding of rhyolite and clinker to produce blended cement shows reduced Engineering, University of energy consumption Engineering and Technology, Peshawar, Pakistan Abstract 2Qadir Enterprises, Peshawar, In this work, pozzolana deposits of district Swabi, Pakistan were investigated Pakistan for partial substitution of Portland cement along with filler. The cem- ent samples were mixed in different proportions and tested for compressive SCIENTIFIC PAPER strength at 7 and 28 days. The strength activity index (SAI) for 10% pozzolana, UDC 666.94(549.1) and 5% limestone blend at 7 and 28 days was 75.5 and 85.0% satisfying the minimum SAI limit of ASTM C618. 22% natural pozzolana and 5% limestone DOI 10.2298/CICEQ141012017A were interground with clinker and in a laboratory ball mill to compare the power consumption with ordinary Portland cement (OPC) (95% clinker and 5% gypsum). The ternary blended cement took less time to reach the same fineness level as OPC due to soft pozzolana and high grade lime stone, indi- cating that intergrinding may reduce overall power consumption. Blended cem- ent production using natural pozzolana and limestone may reduce the energy consumption and greenhouse gas emissions. Keywords: ternary blended cement, natural pozzolana, limestone filler, cement production.

Natural have been employed in civil cementitious materials in the process resulting in red- works since ancient times [1]. The addition of natural uction in fuel consumption required for clinker form- volcanic rocks to cement or to mixes results ation, CO2 emissions, as well as enhanced durability in improving chemical and physical properties such as and life cycle performance of the concrete structures reduction in heat release when mixed with water, [3]. good ultimate compressive strength, low permeability, The addition of natural pozzolans to form blended high resistance to sulphates and chloride attacks, and cements has been investigated extensively by reduced alkali-silica reaction [2]. Addition of limestone researchers previously demonstrating benefits in red- as a filler increases the early strength development in uction of energy consumption, green house gas emis- concrete; however, chloride ion diffusion may also sions, and cost [4-7]. The addition of natural pozzo- increase depending upon the blending ratio. A careful lans is constrained due to increase in hydration choice of additives and their blending ratios may yield requirements and decrease in early strength develop- cements with enhanced performances. Cement pro- ment [8]. Blending of cement with natural pozzolans duction may become more sustainable by addition of and others additives offers the advantage of exploit- ing characteristic of various materials while compen- Correspondence: M. Imran Ahmad, Department of Chemical sating for disadvantageous features [9-14]. Blended Engineering, University of Engineering and Technology, Pesha- cements are also produced on a commercial scale, war, Pakistan. for example in Algeria, using natural pozzolana and E-mail: [email protected] Paper received: 12 October, 2014 limestone [15]. Paper revised: 12 October, 2014 Paper accepted: 1 June, 2015

41 M. IMRAN AHMAD et al.: SUSTAINABLE PRODUCTION OF BLENDED CEMENT… Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016)

Natural pozzolans are known to react with the these extruded to the ground surface. The estimated calcium hydroxide formed during the reaction of ordi- quantity of deposit above ground level is 9.2 million nary Portland cement with water. The reaction of tons, while the quantity below ground level needs to silica component of pozzolana with calcium hydroxide be estimated after proper drilling. The pozzolana is relatively slow, and produces calcium silicate hyd- deposits of Swabi are whitish in color without any rates. The addition of pozzolana also results in inc- significant variation in size and composition [21]. rease of cementitious aluminates resulting from the reaction of alumina component of pozzolana with MATERIAL AND METHODS calcium hydroxide and sulphate ions [16-19]. This research work attempts to explore the pro- Pozzolana samples were collected and tested duction of blended cements in Pakistan through addi- for chemical, mineralogical composition, using XRF, tion of natural pozzolana for sustainable growth of the XRD, and other properties essential to determine cement, and construction sector. Natural pozzolana feasibility of use as cementitious material. Ordinary deposits are available in different areas of KPK, Portland cement (OPC) was used with natural pozzo- Pakistan such as in Karak, Mohmand agency, Swabi lana from Swabi, Pakistan and high grade limestone and Swat. Bentonite deposits of Karak district have (consisting of more than 95% ) been investigated for partial substitution of ordinary from the quarry of Askari Cement, Nizampur, Pakis- Portland cement in mortars and concrete [20]. tan. The chemical composition of OPC, natural poz- In this paper the natural pozzolana deposits of zolana, and limestone employed in this work are Swabi are investigated for production of ternary shown in Table 1. It may be observed from Table 1 blended cement. Pozzolana deposits are located in that the minimum requirement of oxides as per ASTM Gohatee, on both sides of Swabi-Mardan road as C618, i.e., the sum of silica, alumina, and iron oxides extrusive rocks, i.e., during geological transformation content should be greater than 70%, for natural poz-

Table 1. Chemical composition (%) of the cement, pozzolana and limestone employed in experiments

Material SiO2 Al2O3 Fe2O3 CaO MgO K2O N2O SO3 Cement 20.5 4.89 4.49 61.41 1.65 0.95 0.22 3.59 Pozzolana 70.61 11.97 0.69 1.95 0.61 4.06 0.0 0.09 Limestone 5.25 1.4 1.2 53.0 0.8 0.05 0.03 0.01

Figure 1. X-ray diffractogram of natural pozzolana.

42 M. IMRAN AHMAD et al.: SUSTAINABLE PRODUCTION OF BLENDED CEMENT… Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016) zolana is satisfied. The mineralogical composition of while total quantity of grinding media was of 96 kg. natural pozzolana is shown in Figure 1. The mineral- Media sizes were 72 (12.56 kg), 63 (21.7 kg), 49 ogical composition as determined by X-ray diffraction (22.06 kg) and 39 mm (10.64 kg). The dimensions of bears similarity with the mineralogical composition of the cylinders were 27 mm, length 37 mm (17.17 kg), a natural pozzolana reported previously [15]. and diameter 25 mm, length 31 mm (11.87 kg). The Pozzolana sample was also tested for loss on feed quantity was 5 kg. The ball mill was drained at ignition using BS–FLS–2011–04 standard. The loss on regular time intervals for sieve analysis using 600, 90 ignition was 1.15%, satisfying the maximum of 10% and 45 μm mesh as well as for Blaine fineness. Insol- specification of ASTM C618. It was concluded based uble residue (IR) was determined by the BS–FLS– on the loss on ignition that natural pozzolana under 20051–04 standard. consideration could be mixed with clinker or cement without any drying through external heat source. RESULTS AND DISCUSSION The formulation of blended cement was varied by substitution of ordinary Portland cement with poz- The chemical composition of ordinary Portland zolana ranging from 5 to 22%, while the limestone cement, pozzolana, and limestone employed in this content was maintained constant at 5%. Ordinary work is shown in Table 1. Portland cement used was from Askari Cement Ltd., It may be observed from Table 1 that the mini- Nizampur, Pakistan, with fineness of 289.3 m2/kg and mum requirement of oxides as per ASTM C618, i.e., residue of 10% on 45 μm. Pozzolana and limestone the sum of silica, alumina, and iron oxides content were separately ground to 370 m2/kg and then mixed should be greater than 70%, for natural pozzolana is with ordinary Portland cement in specified ratios, as satisfied. The compressive strength (MPa) at 7 and shown in Table 2. Mortar cubes were casted and 28 days of various blends is shown in Table 2. tested for compressive strength at 7 and 28 days. Mortar cubes were prepared using 1:3 ratio of cement Table 2. Compressive strength of tested composite cement mortars and sand, taking 200 g of cement and 600 g of sand. Cement Pozzolana Limestone Compressive strength, MPa Cube dimensions were 70.1 mm×70.1 mm×70.1 mm. % % % 7 days 28 days ° Curing of cubes was carried out at 27±2 C water 100 0 0 54.7 61.8 temperature in curing tank until the day of testing. 90 5 5 44.3 58.3 Table 3 presents the composition, loss on ignition, 85 10 5 41.3 52.5 specific surface area, i.e., Blaine and residue of var- 80 15 5 40.0 49.6 ious blends. 73 22 5 37.1 48.3 Strength activity index (SAI) was calculated for all the blends to test for minimum specification of 75% The strength activity index calculated using Eq. as per ASTM C618. The strength activity index is (1) for various blends at 7 and 28 days is shown in defined as [22]: Figure 2. 100A It may be observed from Table 2 and Figure 2 SAI = (1) B that increasing the weight percentage of pozzolana above 10% while maintaining limestone percentage where A = average compressive strength of the fixed at 5% resulted in violation of the ASTM C618 blended cement mortar cubes and B = average com- specification, i.e., below the specified limit of 75%. pressive strength of the cement mortar cubes without Alternatively, it may be noted that substitution of more any substitution. than 15% of ordinary Portland cement, using pozzo-

lana and limestone, in cement mortars resulted in sig- The effect of pozzolana substitution on power nificant loss of compressive strength at 7 days. The consumption was investigated by grinding clinker, two blends (80/15/5 and 73/22/5) with significant loss pozzolana, high grade limestone and gypsum mix, of compressive strength at 7 days show a recovery of and compared with grinding of clinker and gypsum in strength between 7 and 28 days, as shown by the a laboratory ball mill. The ball mill consisted of a satisfactory SAI value at 28 days. All the cement com- single chamber manufactured by Wuxi Building Mat- posite mortars showed an increase in compressive erial Instrument & Machinery Co, China. The labor- strength after 7 days indicating that between 7 and 28 atory ball mill had a diameter of 560 mm and length of days both the OPC hydration and pozzolanic hydra- 520 mm. The feed size was less than 30 mm as per tion reactions contributed to strength development. the mill requirement. The installed motor was 1.5 kW The reduction in early strength development is char-

43 M. IMRAN AHMAD et al.: SUSTAINABLE PRODUCTION OF BLENDED CEMENT… Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016)

Figure 2. Strength activity indices for composite cement mortars after 7 and 28 days. acteristic to use of natural pozzolans due to the need loying a mix of clinker 68%, pozzolana 22%, lime- for longer duration of moist-curing. However, this stone 5% and gypsum 5% and compared with the shortcoming is partially addressed by addition of lime- grinding to produce OPC, i.e., clinker 95% and gyp- stone filler, which accelerates the reactions in cement sum 5%. The specific surface area obtained after pastes and mortars [15]. regular time intervals for the ternary blended cement The chemical composition and physical pro- and OPC are shown in Table 4. perties such as Blaine fineness and residue are shown in Table 3. Table 4 Grinding test for OPC and blended cement

Blaine fineness, m2/kg Table 3. Chemical composition (%) and physical properties of Grinding time, min OPC Blended cement blended cement composites 10 163.3 245.8 OPC/Pozzolana/Limestone blend Component 15 183.8 301.9 100/0/0 90/5/5 85/10/5 80/15/5 73/22/5 20 239.5 363.4 SiO2 20.5 22.84 25.65 28.22 32.48 25 275.3 408.5

Al2O3 4.89 5.21 5.79 6.3 7.15

Fe2O3 4.49 4.43 4.5 4.56 4.68 It may be observed from Table 4 that blended CaO 61.41 58.56 55.17 51.39 45.88 cement was easier to grind compared to OPC due to MgO 1.65 1.47 1.22 1.00 0.62 reduced percentage of clinker in blended cement. The

K2O 0.95 1.06 1.20 1.32 1.51 grinding tests indicate that inter-grinding of pozzolana

N2O 0.22 0.22 0.23 0.23 0.23 and limestone with clinker and gypsum in the cement

SO3 3.59 3.26 3.09 2.88 2.54 mill may reduce the power consumption required to LOI 2.12 3.74 3.52 3.67 3.69 achieve the specified fineness for cement. Physical properties Blaine fine- 289.3 330.6 335.6 342.2 361.2 CONCLUSIONS ness, m2/kg Residue, % 8.50 10.80 12.60 14.40 15.40 In this paper, partial substitution of ordinary Portland cement with natural pozzolana from the Swabi district and limestone was investigated for pro- It may be observed from Table 2 that the sub- duction of ternary blended cement in Pakistan. Poz- stitution of OPC with pozzolana and limestone results zolana percentage was varied from 5 to 22%, to in reduction in early strength development. However, substitute OPC, while maintaining a fixed percentage the specific surface area, i.e., Blaine fineness inc- of limestone. It is concluded based on the results of reases, indicating that pozzolana is a relatively soft compressive strength at 7 and 28 days that up to 15% additive. The partial substitution of OPC with pozzo- OPC may be substituted with 10% pozzolana and 5% lana and limestone may also result in further saving in limestone in cement composites. The use of ternary energy consumption through reduction in power con- blended cement composites in civil works would need sumption requirement in the cement mill for grinding further investigation to determine the long term strength of clinker and gypsum. The grinding test for blended development, i.e., after 28 days, as well durability cement was carried out in a laboratory ball mill emp- through sulphate resistance, and permeability tests.

44 M. IMRAN AHMAD et al.: SUSTAINABLE PRODUCTION OF BLENDED CEMENT… Chem. Ind. Chem. Eng. Q. 22 (1) 41−45 (2016)

The power consumption required in the cement [9] J. Bai, B. Sabir, S. Wild, J.M. Kinuthia, Mag. Concr. Res. mill was inferred through investigation on a laboratory 52(2) (2000) 153-162 ball mill indicating that intergrinding of pozzolana and [10] R. Bleszynski, R.D. Hooton, M.D.A. Thomas, C.A. limestone with clinker and gypsum may reduce the Rogers, ACI Mater. J. 99(5) (2002) 499-508 overall power consumption of cement production. [11] M.F. Carrasco, G. Menendez, V. Bonavetti, E.F. Irassar, Cem. Concr. Res. 35(7) (2005) 1324-1331 Acknowledgement [12] J.M. Khatib, J.J. Hibbert, Constr. Build. Mater. 19(6) The support of Askari Cement, Nizampur, Pakis- (2005) 460-472 tan is acknowledged for providing assistance in test- [13] Z. Li, Z. Ding, Cem. Concr. Res. 33(4) (2003) 579-584 ing of composition and properties of samples. [14] G. Menendez, V. Bonavetti, E.F. Irassar, Cem. Concr. Compos. 25(1) (2003) 61-67 REFERENCES [15] M. Ghrici, S. Kenai, M. Said-Mansour, Cem. Concr. Compos. 29 (2007) 542-549 [1] S.H. Kosmatka, B. Kerkhoff, W.C. Panarese, N.F. Mac- [16] V.L. Bonavetti, V.F. Rahhal, E.F. Irassar, Cem. Concr. leod, R.J. McGrath, Design and Control of Concrete Mix- Res. 31(6) (2001), 853-859 th ture, 7 ed., Portland Cement Association, Skokie, IL, [17] M. Heikal, H. El-Didamony, M.S. Morsy, Cem. Concr. 2002 Res. 30(12) (2000) 1827-1834 [2] ACI, ACI Mater. J. 91(4) (1994), 410-426 [18] G. Kakali, S. Tsivilis, E. Aggeli, M. Bati, Cem. Concr. Res. [3] P.K. Mehta, ACI SP-178, Farmington Hills, MI, 1998, pp. 30(7) (2000) 1073-1077 1-25 [19] A.M. Neville, Properties of Concrete, 3rd ed.,. Pearson, [4] P.K. Mehta, Cem. Concr. Res. 11 (1981) 507-518 Harlow, 1981 [5] F. Massazza, Cem. Concr. Compos. 15(4) (1993) 185-–214 [20] J. Mirza, M. Riaz, A. Naseer, F. Rehman, A.N. Khan, Q. [6] A. Tagnit-Hamou, N. Pertove, K. Luk, ACI Mater. J. Ali, Appl. Clay Sci. 45 (2009), 220-226 100(1) (2003) 73-78 [21] A.H. Kazmi, S.G. Abbas, Metallogeny and Mineral [7] L. Turanli, B. Uzal, F. Bektas, Cem. Concr. Res. 35 Deposits of Pakistan, Orient Petroleum Inc., Islamabad, (2005) 1106-1111 2001 [8] B. Uzal, L. Turanli, Cem. Concr. Compos. 34 (2012) 101- [22] ASTM, Standard Specification for Coal and Raw –109 or Calcined Natural for Use in Concrete. C618- -08a. ASTM International, West Conshohocken, PA, 2008.

MUHAMMAD IMRAN AHMAD1 ODRŽIVA PROIZVODNJA CEMENTNE MEŠAVINE MUHAMMAD SAJJAD1 IZ PAKISTANA UZ DODATAK PRIRODNOG 2 IRFAN AHMED KHAN PUCOLANA AMINA DURRANI2 1 ALI AHMED DURRANI U ovom radu istraživana su nalazišta pucolana u oblasti Svabi (Swabi, Pakistan), radi 1 SAEED GUL parcijalne zamene portland cementa uz dodatak krečnjaka kao punioca. Komponente su 1 ASMAT ULLAH mešane u različitim odnosima, a uzorci betona su testirani na pritisnu čvrstoću posle 7 i 28 1Department of Chemical dana. Indeks pritisne čvrstoće (SAI) za mešavine od 10% pucolana i 5% krečnjaka posle 7 Engineering, University of i 28 dana bio je 75,5 i 85,0%, redom, što zadovoljava minimalnu SAI granicu prema ASTM Engineering and Technology, C618. Smeša sa 22% prirodnog pucolana i 5% krečnjaka je samlevena sa klinkerom i Peshawar, Pakistan gipsom u laboratorijskom kugličnom mlinu radi poređenja potrošnje energije sa običnim 2 Qadir Enterprises, Peshawar, portland cementom (OPC) (95% klinkera i 5% gipsa). Trojnoj cementnoj mešavini je tre- Pakistan balo manje vremena da se postigne ista finoća kao OPC zbog prisustva mekih faza puco- lana i visokog udela krečnjaka, što pokazuje da je moguće smanjiti ukupnu potrošnju ener- NAUČNI RAD gije. Evidentno da proizvodnja cemente mešavine, koristeći prirodni pucolan i krečnjak, može da smanji potrošnju energije i emisiju gasova staklene bašte.

Ključne reči: trojna cementna mešavina, prirodni pucolan, krečnjački punioc, proizvodnja cementa.

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