E-ISSN : 2541-5794 P-ISSN : 2503-216X Journal of Geoscience, Engineering, Environment, and Technology Vol 7 No 1 2022 Marin, J. et al./ JGEET Vol 7 No 1/2022 27 RESEARCH ARTICLE Characteristics of Kedondong Trass and Bobos Trass as Cement Raw Material, Cirebon, West Java, Indonesia Jenian Marin1,*, Tri Winarno1, Shofiana Nadia Fairuz1 1 Department of Geological Engineering, Diponegoro University, Jl. Prof. SOedarto, SH, Tembalang, Semarang, Jawa Tengah, Indone sia * Corresponding author : jenianmarin@gmail.com Tel.:+62-82-116-548-503 Received: Nov 26, 2021; Accepted: Mar 30, 2022. DOI: 10.25299/jgeet.2022.7.1.8180 Abstract The use of cement materials in construction continues to increase every year, consumes lots of raw material and emits CO 2 from clinker production. To eliminate this negative effect, alternative materials are needed. Trass is natural pozzolan which is formed from silica-alumina rich volcanic rocks. As supplementary cementitious material, trass is sufficiently durable and reduce clinker proportion in cement mixture, thus more environmentally friendly. This research aims to determine characteristics and composition of Kedondong trass and Bobos trass, Cirebon, West Java as raw material for pozzolan cement. The study was conducted using petrography and XRD analysis to determine mineralogy of rocks. XRF analysis was carried out to determine chemical composition as well as other tests to determine trass quality. Kedondong trass is originated from andesite intrusion and andesitic breccia, while Bobos trass is formed from hypersthene- andesite intrusion. Based on mineralogy analysis, trasses have similar mineral composition consist of plagioclase, quartz, pyroxene, hornblende, and sanidine. XRD analysis shows abundance of cristobalite and tridymite from each samples. This mineralogy is confirmed by geochemistry result, which is the samples contain more than 70% SiO2 + Al2O3 and less than 4% SO3. Other chemical characteristics that have been tested are moisture content, ignition loss, and clay content in which all of those parameters meet the industrial standard for cement material. Keywords: Trass, Supplementary Cementitious Material (SCM), Pozzolanic Cement, Cirebon 1. Introduction Cement production in Indonesia has dubbed to be one of the largest in the world. By the last decade, domestic sales is consistently rising every year to fulfill demand from development of national infrastructures.The highest growth is in 2011, which was 17.7% with volume of 48 million tons. Later, local and multinational cement producers are expanding their production capacity (Asosiasi Semen Indonesia, 2018). Regular Portland cement production has massive carbon footprint which significantly contribute to climate change. More than 4 billion tonnes of cement manufactured each year emits for around 8% of the world’s CO2 emissions (Lehne and Preston, 2018). This high emissions is linked to the clinker production, a mixture of raw materials fused together by heat, for the main ingredient of cement. Clinker is a product of chemical conversion called calcination in which limestone (CaCO3) is converted to lime (CaO). During its process, CO2 is released in the kiln at 600 – 900 C (Gibbs et al., 2001) as follows: CaCO3 + heat  CaO + CO2……………. (1) Natural pozzolans can be used as clinker substitution in cement blends because its cementitious properties, known as pozzolanic activity. Pozzolan is defined as siliceous and aluminous materials that has little to no cementitious properties on its own, but when finely grounded and combined with calcium hydroxide in water, it has ability of hydraulic binding (Çullu et al., 2016). Benefit of pozzolans including low heat of hydration, high strength, low permeability, and low alkaline-silica reaction. Mineral deposits with pozzolanic Rocks of volcanic origin, particularly pyroclastic materials from explosive eruption possess pozzolanic properties without extensive processing. Trass is one of variety of volcanic ash which possesses pozzolanic properties. As a volcanic active regions, Indonesia is rich in volcanic rocks which some of these are already used as natural pozzolan in national’s cement industry. One of national cement manufacturer operate in the study area (Fig.1) at Palimanan, Cirebon Regency, West Java, produced ordinary Portland cement and pozzolanic cement. By local people, natural pozzolans in the study area is more commonly referred to as trass. Kedondong and Bobos are two quarries location used by the manufacturer, hence the name, Kedondong trass and Bobos trass. Aims of this study is to provide information on trass characteristics and its prospect in this country as supplementary cementitious materials (SCM). 2. Geological setting Study area is part of Bogor Zone physiography, a Neogene sedimentary sequences intruded by many volcanic rocks, now is a strongly folded anticlinorium (Satyana et al., 2002; Van Bemmelen, 1949). Rock formations in the study area is mainly dominated by 28 Marin, J. et al./ JGEET Vol 7 No 1/2022 Plio-Pleistocene volcanic rocks on top of Miocene- Pliocene marine sediments (Fig.1). Kromong Limestone consists of Miocene reef limestone complex in the northern part of study area, which is the main material for cement. Kaliwangu Formation is Pliocene marine sediments rich in molluscs, consist of shale intercalated with sand and gravel. On top of those, Plio-Pleistocene volcanic rocks are andesitic-tuffaceous Kromong Breccia, undifferentiated volcanic rocks, and andesite intrusions (Aswan et al., 2013; Djuri, 1995; Jambak et al., 2015). Fig 1. Location and regional geology map of study area 3. Methodology 3.1 Research methods From geological map, the two locations have different rock type in which Kedondong trass is originated from Kromong Breccia while Bobos trass is originated from Andesite Intrusion. Samples were obtained directly in the field from existing quarries of two locations, 9 samples from Kedondong and 10 samples from Bobos. Laboratory analysis were carried out to determine characteristics of trass as follows: a. Thin section samples were prepared to identify mineralogical and petrographical characteristics under polarizing microscope. Both fresh rock and altered rock samples were used to compare this aspect. b. X-ray diffraction (XRD) analysis of powdered bulk samples was conducted to determine whether silica minerals were present in trass. This is to accomodate one of requirement in which trass must contain crystalline silica such as tridymite and cristobalite. Geochemistry of samples were determined using X-ray fluorescence (XRF) analysis, most importantly to identify some of the major elements comprising SiO2, Al2O3, Fe2O3, CaO, MgO, Na2O, K2O, and SO3. c. Moisture content was determined by weighing 100 gr of samples before and after drying 1-2 hours in the oven. For loss on ignition parameter: 1 gr of finely ground samples was heated in the crucible at 500°C for 30 minutes. Followed by igniting the samples in the furnace of 1000°C for 1 hour. After being cooled in the dessicator, samples are weighed again. d. Clay content was determined by adsorption test: mixing 5 gr of finely ground samples 25 ml aquades using magnetic stirrer for 5 minutes, and then adding 2 ml methylene blue. Clay particle will react and adsorbed by methylene blue. Stain test on filter paper was conducted until a light blue halo showed in the paper by adding more methylene blue, that means all clay was adsorbed (Chiappone et al., 2004). The more methylene blue is added to show the blue halo, the higher is clay content in the samples. 3.2 Specifications of trass The intrinsic capacity of pozzolans is depend of chemical composition, which is varies greatly in volcanic deposits (Yu et al., 2017). After chemical criteria meets the requirement, most raw materials need to be processed to meets the physical criteria such as fineness, moisture, and strength (Sleep and Masley, 2018). American Standard for Testing Materials (ASTM) C618-94a 1993 (ASTM, 1993) specifies standard chemical composition of raw and calcined natural pozzolans for use in concrete as shown by Table 1. According to national standard of SNI-04-1989-F (Badan Standardisasi Nasional, 1989), trass can be used Sources: DEM SRTM of Cirebon (USGS, 2020) Regional Geology Map (Djuri, 1995) Datum UTM WGS 1984 Zone 48 S Marin, J. et al./ JGEET Vol 7 No 1/2022 29 in light construction with several requirements based on building classes (Table 2.). Trass commonly used for Portland Pozzolan Cement (PPC) mixture, concrete, plastering, or brick mixture. Table 1. ASTM C618-94a 1993 for natural pozzolans. Chemical compound Wt % range SiO2 40.76 – 56.20 Al2O3 17.35 – 27.95 Fe2O3 7.35 – 13.15 H2O 3.35 – 10.70 CaO 0.82 – 10.27 MgO 1.95 – 8.05 SiO2 + Al2O3 minimum 70.0% SO3 maximum 4.0% Na2O maximum 1.5% Moisture content maximum 3.0% Loss in ignition maximum 10.0% Table 2. Trass requirement from SNI-04-1989-F Requirement Class 1 Class II Class III 1. Free moisture at 110°C in wt% < 6 6-8 8-10 2. Fineness (% maximum of particle larger than 0,21 mm) < 10 10-30 30-50 3. Maximum binding time in days 1 2 3 4. Compressive strength after 14 days (kgf/cm2) 100 100-75 75-50 Based on ASTM and SNI standard, PT. Indocement Tunggal Prakarsa Tbk at Palimanan Unit establishes a modified standard parameter of trass for its manufacture as shown by Table 3. To meet the standard several samples of trass must go through chemical and physical analysis such as XRF analysis, moisture, loss on ignition, and clay content. XRD analysis is also conducted to make sure any crystalline silica presents in trass samples. Table 3. Trass quality requirement in PT. Indocement Tunggal Prakarsa Tbk Palimanan Unit Parameter Requirement 1. Total SiO2 + Al2O3 Minimum 70.0 wt. % 2. SO3 Maximum 4.0% 3. Moisture 1% – 5.6% 4. Loss on ignition Maximum 10% 5. Clay content Maximum 5% 6. Silica Must be present (tridymite, cristobalite) 5. Results 5.1 Lithology of the quarries Lithology observed in the field from the two quarry are slightly different as expected by regional geology map. Kedondong quarry which from regional geology map is part of Kromong Breccia, is covered by two type of andesitic rocks (Fig.2). The first one is andesitic breccia which characterized by moderately weathered, brownish color, cobble-pebble sized andesite fragment inside tuffaceous matrix. This breccia is intruded by dark-grey andesite which formed a morphologically distinctive intrusion hill than its surroundings. Andesite has sheeting joint structure, intensively weathered with some fresh andesite still present, composed by plagioclase and hornblende phenocryst in fine grained groundmass. Fig 2. Lithology found in Kedondong quarry Fig 3. Weathered hypersthene-andesite in Bobos quarry N N N 30 Marin, J. et al./ JGEET Vol 7 No 1/2022 Bobos quarry located in volcanic hills morphology and identified as Andesite Intrusion from regional geology map. From the quarry observation, we also found fine grained hypersthene-andesite which consistent to the reference. Exposed rocks also exhibit moderately to highly weathered condition, resulted in softer and yellowish rocks (Fig.3). Dominant phenocryst is plagioclase with pyroxene accessory in aphanitic groundmass. In both location, the degree of weathering greatly changes original texture, structure, and overall appearance of rocks even though the fresh rocks are still present to be observed. Beside of original rock composition, this process is important to bring in pozzolanic properties of trass deposits. 5.2 Mineralogy and petrography of rocks Mineralogy is inspected by thin section observation of samples from both locations. While both Kedondong and Bobos have similar composition of andesitic rocks, there is slightly difference in mineralogical and petrographical aspect as shown by Table 4. Both rocks are composed of plagioclase as dominant phenocryst (40-50%), pyroxene, hornblende, quartz, and opaque mineral. The fragments have similar composition with andesite from intrusion. Bobos andesite contains more pyroxene (hypersthene) and less glassy groundmass (Fig.6). Other than fresh hand specimens, altered samples were also being inspected through thin section, showing leached texture, altered rim in some phenocryst, and finer groundmass in all rocks. Kedondong andesite has less phenocryst and more glassy groundmass than Bobos andesite (Fig,4). Meanwhile, thin section of andesitic breccia from Kedondong shows abundant volcanic glass matrix, along with minor fine grained crystal and opaque mineral surround the andesitic fragments (Fig.5). Table 4. Mineralogy of rocks from Kedondong and Bobos Samples Mineral content Characteristics Kedondong Andesite Plagioclase (labradorite), hornblende, pyroxene, quartz, opaque minerals Porphyritic texture, glassy groundmass Andesitic Breccia Volcanic glass, plagioclase, quartz, opaque mineral, hornblende Tuff as dominant matrix supporting andesite fragments Bobos Hypersthene- Andesite Plagioclase (labradorite), orthopyroxene, hornbende, quartz, opaque mineral Porphyritic texture, little to no glassy groundmass Fig 5. Thin section of matrix part from Kedondong’s andesitic breccia: (A) plane polarized and (B) cross polarized Fig 6. Thin section of Bobos andesite: (A) plane polarized and (B) cross polarized (Pl : Plagioclase, Qz : Quartz (I10), Hb : Hornblende (B10), Op : Orthopyroxene (H5)) 0 0,5 mm 0 0,5 mm Marin, J. et al./ JGEET Vol 7 No 1/2022 31 5.3 Trass mineralogy The result from petrographical analysis is supported by XRD analysis of powdered bulk sample, as summarized by Table 5. All of the samples show R-WP less than 10% which are considered good and fit (Toby, 2021). Although there are two different rocks in Kedondong, they are regarded as one because in this section, we are focusing on trass characteristics which is the main commodity of the quarry. According to the XRD analysis, trass samples from both quarry contain quartz, plagioclase, kaolinite, sanidine, tridymite, cristobalite, and hematite. Tridymite and cristobalite are crystalline silica which are important to contribute pozzolanic activity. Kedondong trass contains 0.67% - 9.42% tridymite and 6.0% - 20.26% cristobalite. At Kedondong quarry, samples from breccia have higher quartz content but lower in other silica. Andesite samples are relatively more weathered than breccias, so it is related to the lower abundance of quartz as resistant mineral. Bobos trass contains 0.8% – 2.52% tridymite and 0.2% - 5.36% cristobalite. The abundance of crystalline silica is differ significantly, where Kedondong trass are higher in tridymite and cristobalite than Bobos samples. This might be correspond with higher percentage of groundmass in Kedondong rocks as shown by petrographical analysis. Kaolinite as alteration product also present, in which Kedondong trass also contains at higher percentage than Bobos trass. Table 5. Test results of XRD analysis from Kedondong and Bobos trasses (in percent) Table 6. Test results of geochemistry analysis using XRF method from Kedondong and Bobos trasses Code Moisture content (%) LOI (%) Clay content (%) Major oxides (wt%) SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O SO3 SiO2 + Al2O3 Kedondong KD 1 10.80 3.26 4.4 69.69 15.84 3.39 3.37 0.00 2.97 1.41 0.024 85.5 KD 2 13.62 3.20 3.0 68.44 15.9 3.61 3.6 0.17 3.01 1.44 0.022 84.3 KD 3 4.15 2.88 2.5 71.67 15.91 3.15 2.98 0.00 3.08 1.57 0.023 87.6 KD 4 1.58 2.27 2.6 70.88 15.06 3.39 3.69 0.00 3.17 1.46 0.020 85.9 KD 5 2.83 1.88 1.6 71.21 15.04 3.25 3.77 0.06 3.37 1.48 0.021 86.3 KD 6 4.77 2.50 2.0 71.15 15.43 3.30 3.45 0.00 3.25 1.45 0.018 86.6 KD 7 3.09 1.74 1.2 71.81 15.43 3.00 3.51 0.00 3.32 1.50 0.020 87.2 KD 8 2.80 2.19 1.6 71.24 15.34 3.32 3.47 0.02 3.20 1.48 0.032 86.5 KD 9 4.08 2.68 1.4 69.67 15.82 3.32 3.69 0.00 3.11 1.54 0.026 85.5 Bobos SLS B1 5.05 4.37 1.6 70.52 15.12 3.03 3.60 0.39 2.99 1.55 0.037 85.6 SLS B2 6.55 5.05 2.0 70.86 15.77 2.89 3.62 0.00 3.35 1.65 0.037 86.6 SLS B3 12.8 2.68 4.6 68.21 16.10 3.17 3.05 0.28 2.66 1.59 0.035 84.8 SLS B4 4.77 2.61 2.5 70.44 15.19 3.24 3.52 0.07 3.38 1.62 0.034 85.6 B2 1.14 1.63 1.4 69.47 14.86 2.91 4.56 0.37 3.58 1.59 0.036 84.0 B3 0.93 2.6 1.2 68.75 14.76 2.61 3.69 0.00 3.57 1.57 0.028 83.0 B4 1.60 1.03 1.4 71.87 15.23 2.97 3.28 0.38 3.69 1.59 0.011 87.0 B5 4.62 2.77 2.6 70.95 15.42 3.28 2.99 0.28 3.07 1.59 0.007 86.3 B6 1.68 1.57 1.8 70.67 15.02 2.94 3.67 0.34 3.55 1.60 0.025 85.6 Code R-WP* Quartz Sanidine Plagioclase Kaolinite Tridymite Cristobalite Hematite Kedondong KD 1 6.86 26.48 20.17 40.55 5.37 0.84 5.73 0.86 KD 2 6.34 26.75 20.75 40.65 4.91 0.93 5.60 0.41 KD 3 6.68 25.88 20.17 41.70 5.65 0.67 5.53 0.40 KD 4 7.67 0.06 12.30 52.38 7.94 8.42 18.70 0.20 KD 5 7.92 0.55 14.35 56.73 2.64 5.47 20.05 0.21 KD 6 7.40 0.33 17.39 53.29 3.43 7.59 17.61 0.36 KD 7 8.05 0.21 17.84 49.24 5.35 8.55 18.17 0.65 KD 8 9.06 0.42 17.36 46.80 8.79 9.4 16.92 0.32 KD 9 7.58 0.19 15.62 46.60 10.57 6.81 19.80 0.41 Bobos SLS B1 6.69 28.95 21.01 42.6 2.83 1.48 3.13 0.13 SLS B2 6.39 30.80 20.90 42.64 1.84 0.80 3.02 0.65 SLS B3 5.48 30.87 21.21 31.18 14.31 1.26 1.17 0.13 SLS B4 6.94 27.97 20.38 47.24 0.31 1.30 2.80 0.28 B2 8.07 23.16 20.94 47.51 0.56 2.52 5.31 0.08 B3 7.93 31.55 20.71 45.60 0.46 1.38 0.30 0.20 B4 7.21 23.89 21.66 46.82 0.16 2.30 5.17 0.11 B5 6.28 33.46 20.47 42.25 2.74 0.94 0.14 0.09 B6 6.83 24.26 20.92 47.67 0.20 1.59 5.36 0.11 32 Marin, J. et al./ JGEET Vol 7 No 1/2022 5.4 Chemical properties of trass In the quarries, trasses have a variation of physical appearance that rather different than fresh rocks. Kedondong trass still contains fine-medium grained minerals between highly weathered groundmass. Bobos trass has finer mineral grains but relatively more compact than Kedondong trass. Chemical properties have been analysed from 18 samples as summarized by Table 6. Result of water content analysis showed that most of samples contain less than 5.6% moisture within the standard criteria, with the exception 4 samples have 6.55%-13.62% moisture. This high moisture results might be correlated with weather, sampling, and preparation technique as the sampling was conducted in January when rainfall is quite high. Loss on ignition (LOI) of samples ranges between 1.57% - 5.05% which is also meet the standard. Clay content in trass samples is determined by adsorption test using methylene blue. The result showed range of 0.4% - 4.6% clay content among the samples. The standard trass has less than 5% clay content. Geochemistry have been analysed from 18 powdered bulk samples using XRF method. All samples have no striking difference chemistry as follows: SiO2 as highest compound at 68.21% - 71.81% and Al2O3 at 14.76% - 16.10%, That make the sum of silica and alumina constituent at about 83.0% - 87.58%. SO3 as one of quality parameter is present at very small amount of 0.007% - 0.037%. The chemical analysis shown the sum of SiO2 + Al2O3 > 70% and SO3 content < 4%. This result is within the standard of chemistry criteria from ASTM and the manufacturer. 6. Quality of trass as SCM Kedondong trass and Bobos trass have been used as supplementary cementitious material by PT. Indocement Tunggal Prakarsa Tbk Palimanan Unit. Bobos quarry located farther than Kedondong quarry from the production facility. Lithology of Kedondong quarry are andesitic breccia and andesite intrusion, composed of minerals such as plagioclase, quartz, pyroxene, and hornblende with abundant volcanic ash/glass. Bobos’ hypersthene-andesite intrusion contains less volcanic glass due to the abundance of crystals. Volcanic glass is a highly reactive, unstable, and vulnerable to alteration. This alteration activates pozzolanic properties in material (Montanheiro et al., 2004). Tridymite and cristobalite are crystalline silica detected by XRD analysis in all trass samples. The presence of silica is also required as a condition that material has pozzolanic activity (Waani and Elisabeth, 2017). Nearly all results from chemical test of trass samples are within the company standard and ASTM standard as well. As natural pozzolans, Kedondong and Bobos trass contain 83% - 87% silica and alumina originated from intermediate volcanic rocks. In addition to durability aspect, silica and alumina compounds are responsible for reacting with hydroxides to produce calcium silica hydrate (C-S- H).This byproduct of water and cement reaction is a strong binding agent which desired in the mixture (Sleep and Masley, 2018). Generally, the higher SiO2 in natural pozzolans, the better pozzolanic activity (Çavdar and Yetgin, 2007). Sulfur trioxide in trass samples is far below the maximum threshold standard of 4%. Moisture content, LOI, and clay content also conform to the standards of trass. Based of all chemical requirement, Kedondong and Bobos trass can be used as one of the cementitious material to reduce clinker. Conclusions Kedondong trass and Bobos trass are originated from andesitic breccia and andesite intrusion, product of intermediate volcanic activity. Rock composition shows abundant volcanic glass and silica as pozzolanic agent. Trass samples have been tested chemically including silica+alumina content, sulphur trioxide content, moisture content, LOI, and clay content. The results are meet the company and ASTM standard for supplementary cementitious material. While all of chemical requirements are within standard, it is recommended to test the physical requirement which correspond to pozzolanic properties such as fineness and compressive strength. Acknowledgements The authors want to thank to Universitas Diponegoro, especially to Faculty of Engineering that has been supported the research fund and the opportunity given to publish the manuscript. The author also thank the support of PT. Indocement Tunggal Prakarsa Tbk. References Asosiasi Semen Indonesia, 2018. Cement Industry in Indonesia. ASI a Glance. URL https://asi.or.id/asi-at-a-glance/ (accessed 9.2.21). ASTM, 1993. Standard specification for fly ash and raw calcined natural pozzolan for use as a mineral admixture in portland cement concrete, in: Annual Book of ASTM Standards: Construction Vol.04.02 Concrete and Aggregates. ASTM, Philadelphia. Aswan, A., Rijani, S., Riza, Y., 2013. Shell Bed Identification of Kaliwangu Formation and its Sedimentary Cycle Significance, Sumedang, West Java. Indones. J. Geosci. 8. https://doi.org/10.17014/ijog.v8i1.151 Badan Standardisasi Nasional, 1989. SNI S-04-1989-F: Spesifikasi Bahan Bangunan Bagian A, Bahan Bangunan Bukan Logam. Jakarta. Çavdar, A., Yetgin, Ş., 2007. Availability of tuffs from northeast of Turkey as natural pozzolan on cement, some chemical and mechanical relationships. Constr. Build. Mater. 21. https://doi.org/10.1016/j.conbuildmat.2006.0 5.034 Chiappone, A., Marello, S., Scavia, C., Setti, M., 2004. Clay mineral characterization through the methylene blue test: Comparison with other experimental techniques and applications of the method. Can. Geotech. J. 41. https://doi.org/10.1139/T04- 060 Çullu, M., Bolat, H., Vural, A., Tuncer, E., 2016. Investigation of pozzolanic activity of volcanic rocks from the northeast of the Black Sea. Sci. Eng. Compos. Mater. 23. https://doi.org/10.1515/secm-2014-0092 Djuri, M., 1995. Peta Geologi Regional Lembar Arjawinangun Jawa Barat. Bandung. Marin, J. et al./ JGEET Vol 7 No 1/2022 33 Jambak, M.A., Syafri, I., Isnaniawardhani, V., Benyamin, Rodriguez, H., 2015. Facies and diagenetic level of the Upper Cibulakan and Parigi Formation, in Randegan and Palimanan Area. Indones. J. Geosci. 2. https://doi.org/10.17014/ijog.2.3.157-166 Lehne, J., Preston, F., 2018. Making Concrete Change: Innovation in Low-carbon Cement and Concrete. URL https://www.chathamhouse.org/2018/06/mak ing-concrete-change-innovation-low-carbon- cement-and-concrete (accessed 11.10.21). Montanheiro, T.J., Yamamoto, J.K., Kihara, Y., 2004. Serra Geral Formation - São Paulo State, Brazil: A potential source for natural pozzolans. Mater. Lett. 58. https://doi.org/10.1016/j.matlet.2003.06.015 Satyana, A.H., Armandita, C., Raharjo, B., Syafri, I., 2002. New Observations on the Evolution of the Bogor Basin , West Java : Opportunities for Turbidite Hydrocarbon Play. Bul. Geol. Inst. Teknol. BANDUNG – Ed. KHUSUS 42 Tahun Pengabdi. Prof. Dr. Soejono Martodjojo, M.Sc. Dep. Tek. Geol. FIKTM, ITB, Bandung, 2002. Sleep, M.D., Masley, M.D., 2018. The use of Mt. Mazama volcanic ash as natural pozzolans for sustainable oil and unpaved road improvement. Portland. https://doi.org/10.15760/trec.202 Toby, B.H., 2021. R factors in Reietveld analysis: How good is good enough? Powder Diffr. 21. https://doi.org/10.1154/1.2179804 Van Bemmelen, R.W., 1949. The Geology of Indonesia. Vol.IA: General Geology of Indonesia and Adjacent Archipelagoes. Government Printing House, The Hague, Netherlands. Waani, J.E., Elisabeth, L., 2017. Substitusi Material Pozolan terhadap Semen pada Kinerja Campuran Semen. . J. Tek. Sipil 24. https://doi.org/10.5614/jts.2017.24.3.7 Yu, L., Li, L., Zhou, S., 2017. Evaluation of pozzolanic activity of volcanic tuffs from Tibet, China. Adv. Cem. Res. 29. https://doi.org/10.1680/jadcr.15.00075 © 2022 Journal of Geoscience, Engineering, Environment and Technology. All rights reserved. This is an open access article distributed under the terms of the CC BY-SA License (http://creativecommons.org/licenses/by-sa/4.0/). http://creativecommons.org/licenses/by-sa/4.0/ http://creativecommons.org/licenses/by-sa/4.0/