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Pada daerah tarik, tulangan di dalam beton memiliki peranan yang sangat penting. Meskipun demikian, tegangan tarik yang terjadi ini bisa saja menyebabkan rentannya tulangan karena retak berpotensi menyebabkan korosi akibat terbukanya celah pada tulangan. Pada makalah ini, cairan mikroba yang terdiri dari bakteri dan jamur bersamaan digunakan untuk meningkatkan kemampuan tarik beton. Selain itu, diusulkan juga penggunaan pemanfaatan agregat kasar buatan (AB) yang mengandung mikroba untuk menggantikan agregat kasar natural (AN) dalam campuran beton pada daerah tarik beton. Cairan mikroba ditambahkan ke dalam campuran beton maupun AB sebanyak 400 hingga 6000 ml/m3. Pengujian kinerja AB dilakukan dengan menggunakan spesimen silinder untuk pengujian kuat tekan beton dan pengujian kuat tarik belah beton. Penambahan cairan mikroba terbukti dapat meningkatkan kuat tekan beton sebesar 12% dan kuat tarik belah beton sebesar 26% pada variasi AN 100%. Didapatkan hasil bahwa substitusi material AB dalam campuran beton dapat menurunkan kuat tekan beton, akan tetapi dapat meningkatkan kuat tarik belah sebesar 6,4% pada variasi 50% AB. Pengendapan mineral kalsium karbonat pada pori-pori di dalam beton serta adanya kapang akibat kerja jamur adalah penyebab meningkatnya lekatan pada matriks di dalam beton. Dibuktikan juga bahwa koloni bakteri bertambah di dalam beton terus bertambah yang berkontribusi pada peningkatan kepadatan beton.

This paper presents the results of an experimental study on Autoclaved Aerated Concrete (AAC) containing Sidoarjo Mud (Lusi) mud to utilize the mud. Autoclaved aerated concrete (AAC) made from fine Artificial Lightweight Aggregate from Lusi mud and Fly Ash as a filler, sintered Lusi mud as the binder, aluminium powder as the foaming agent. Autoclaving process was conducted at 14 bars for 6 hours. AAC prepared in 3 (three) compositions, based on the variation of filler. The filler used in the research were sands (M-sand), fine ALWA made from Lusi mud (M-0), and fine ALWA made from Lusi mud mixed by fly ash (M-50). The workability of AAC investigated in this research was compressive strength of the AAC after 14 days, density, and X-Ray Diffraction. Experimental data showing that the compressive strength of AAC depends on the filler that is used, AAC classified at AAC-3 and AAC-4. The density of all the AAC can’t be classified as lightweight concrete. Experiment data showed the density occurs at 1148,0 kg/m3 to 1206,4 kg/m3. Chemical compounds of AAC with fine ALWA filler consisted of quartz, hematite, tobermorite, calcite, anorthite, magnetite, lime, and forsterite.

This study presents the use of reclaimed asphalt pavement (RAP), and fly ash as artificial aggregate and filler in asphalt concrete. Because of the limited availability of natural materials, infrastructure development has become a concern. Therefore, it is necessary to reuse and recycle waste materials. One such innovation is artificial aggregates. The disadvantage of RAP is that its gradation exceeds the standard; its asphalt penetration and ductility exceed the requirements. The weaknesses of artificial aggregate are high water absorption, spherical shape, and low aggregate interlocking. In this study, the artificial aggregate was produced using the fly ash and alkali activator. Alkali activator consisted of Na2SiO3 and 8M NaOH at a ratio of 2.5. The mixtures containing different percentages of artificial aggregate (45, 55, 65, and 75%) were produced, and the fly ash filler content was 5%. Different tests including XRF, SEM, and Marshall tests were conducted. The artificial aggregate is hydrophilic owing to the high silica content; thus, it has high water absorption. This results in a low adhesion between the asphalt and aggregate. The best composition of asphalt concrete is 55% artificial aggregate, RAP, fly ash filler, and asphalt. The asphalt concrete containing artificial aggregate has high stability and is stiff and light. However, it requires a high asphalt content because of high water absorption. It is unsuitable for application in high traffic roads but suitable for medium traffic ones.

This paper aims to encourage the Indonesian government to review the 2014 Government Regulation (PP) number 101 related to coal-ash. Fly ashes at power plants overload the landfills and requires complete handling solution. The utilization of fly ash in Indonesia are facing the issues, one of these is the categorization of fly ash as a hazardous waste. As a result, its utilization requires permissions from the ministry of environment and forestry. In this paper, a comparative study of fly ash classification as hazardous waste in India, United States of America, China and Vietnam was conducted. India and China are the coal importer from Indonesia. US regulation was once referred when drafting PP number 101. Vietnam is chosen as comparison in Southeast Asia. The Toxicity Characteristic Leaching Procedure (TCLP) results of fly ashes from 16 Indonesian power plants proved that their toxic content was lower than the TCLP parameters in the regulation. Acute Oral Toxicity Test (LD50) results showed that fly ash and bottom ash with dosage up to 7000 mg/kg did not cause fatalities. This study is a reference for the Indonesian government to verify the status of fly ash to be utilized as much as possible in various fields.

The study of geopolymers has become an interesting concern for many scientists, especially in the infrastructure sector, due to having inherently environmentally friendly properties and fewer energy requirements in production processes. Geopolymer attracts many scientists to develop practical synthesis methods, useful in industrial-scale applications as supplementary material for concrete. This study investigates the geopolymerization of fly ash and geothermal silica-based dry activator. The dry activator was synthesized between NaOH and silica geothermal sludge through the calcination process. Then, the geopolymer mortar was produced by mixing the fly ash and dry activator with a 4:1 (wt./wt.) ratio. After mixing homogeneously and forming a paste, the casted paste moved on to the drying process, with temperature variations of 30, 60, and 90 °C and curing times of 1, 3, 5, 7, 14, 21, 28 days. The compressive strength test was carried out at each curing time to determine the geopolymer’s strength evolution and simulate the reaction’s kinetics. In addition, ATR-FTIR spectroscopy was also used to observe aluminosilicate bonds’ formation. The higher the temperature, the higher the compressive strength value, reaching 22.7 MPa at 90 °C. A Third-order model was found to have the highest R2 value of 0.92, with the collision frequency and activation energy values of 1.1171 day−1 and 3.8336 kJ/mol, respectively. The utilization of coal fly ash and silica geothermal sludge as a dry activator is, indeed, an approach to realize the circular economy in electrical power generations.

This study was conducted as a part of a research to assess the influence of the volumetric properties of geopolymer artificial aggregates made of fly ash to the performance of asphalt mixture to be used in pavement layers. This paper presents the parameters adopted during the production of geopolymer artificial aggregates which may affect the volumetric properties and the structure of the aggregates. The investigated volumetric properties included specific gravity and water absorption. In the experiment laboratory, two variables were utilized for producing the artificial aggregates, which might affect the considered volumetric properties. Those variables are pan-granulator slopes and alkaline ratios (the ratios of Sodium Silicate to Sodium Hydroxide). The pan-granulator slopes were set at 3 different angles, i.e. 45o, 50o, and 55o. The selected alkaline ratios were 1.5, 2.0, 2.5, and 3.0. The test results indicated that the best volumetric properties were obtained at a slope of 50oand alkaline ratio of 2.5. The bulk specific gravity values at the best volumetric properties were found to be: 1) oven dry at 1.9 grams/cm3; 2) saturated surface dry (SSD) at 2.0 grams/cm3, and 3) apparent at 2.1 grams/cm3with 6% water absorption. In addition, the interfacial transition zone and microstructure aggregates were examined by using Scanning Electron Microscope (SEM). In this study, it was found that there were effects of Na2SiO3/ NaOH ratios and the granulation method on the volumetric properties.

This paper presents more convenient deflection function that properly substitutes slow converging series function by Naiver for simply supported quadrilateral thin plate. The formulation of the deflection function was conducted by using variational approach. During formulation, Rayleigh-Ritz procedures was used and coordinate function that satisfies kinematic boundary condition and the minimum potential energy principle was developed. In addition to coordinate function, modification factor was applied to the main function for curve fitting purpose. To validate the current study, comparisons were done with Navier’s solution and finite element analysis. The results shown that the deviation for mid-point deflection of current study was very small, i.e. around 0.03%, from Navier’s solution. Furthermore, it has been investigated that finite element analysis also resulted closer result with current study. This study will minimize the computation time by eliminating long and slowly converging series coordinate function in Navier’s solution.

We isolated a strain of Bacillus safensis, which we called IDN1, from natto sold in Indonesia. In order to gain insights into its genomic structure and understand its biology, we used the Oxford Nanopore MinION platform followed by PCR to verify the ends and determine its full circular genome sequence.

This paper presents the benefits of PVA fibers in improving the mechanical properties of class F fly-ash-based geopolymer concrete. The activator used in the geopolymer was 8M sodium hydroxide (NaOH) and sodium silicate (Na2SiO3), with a mass ratio of Na2SiO3 to NaOH varied from 1.5 to 2.5. Cylindrical specimens with a diameter of 100 mm and a height of 200 mm were prepared for mechanical strength tests. The PVA fibers in the geopolymers were fixed at 0.4%, 0.6%, and 0.8% by total volume. Some mechanical tests were carried out, including compression, splitting, direct tensile and elastic modulus tests. It was found that the mixture with a ratio of alkalis of 1.5 and the PVA fiber content of 0.4% had the best workability. The highest compressive strength was obtained in a mixture with alkali activator ratios of 1.5 and 2.0, and with 0.6% fiber addition. The ratio of the tensile (and splitting-tensile) strength to compressive strength was found to increase with the certain amount of PVA fibers and the ratio of the alkali activators. The workability issue and fiber direction in the concrete were the dominant factors influencing the properties of geopolymer concrete.

This paper presents the effect of polyvinyl alcohol (PVA) fibre on the bond strength in geopolymer concrete. The main focus of the study is to investigate how bond performance is affected by varying the amount of PVA fibre content. The PVA fibre content of 0 %, 0.2 %, 0.4 %, 0.6 % and 0.8 % by volume of concrete were utilized. Alkali activated class F fly ash was used to prepare the concrete specimens. Moreover, the Ordinary Portland cement (OPC) specimen was also prepared to conduct the comparative study. The results showed that the application of PVA fibre improves the bond resistance between the pull-out bar and concrete matrix. It has been investigated that the utilization of PVA fibre in geopolymer concrete improves up to 25.9 % bond strength as compared with the concrete without PVA fibre. The addition of PVA fibre provides a more ductile mode of failure in both geopolymer and OPC concrete than to the concrete without PVA fibre. For the different percentages of PVA fibre used, the specimen with 0.6 % PVA fibre shows maximum compressive strength, splitting and bond strength. The comparative study reveals that the specimen with and without PVA fibre blended geopolymer concrete shows higher bond strength than OPC concrete.

Infrastruktur dan fasilitas transportasi merupakan hal-hal yang sangat diperlukan untuk menunjang aktivitas masyarakat, pembangunan dan pengembangan wilayah. Manajemen aset infrastruktur dan fasilitas transportasi perlu dikelola dengan baik. Dalam rangka penghematan sumberdaya alam, maka pemanfaatan RAP sebagai hasil pengerukan sebagian perkerasan jalan sangat diperlukan. RAP merupakan material sisa, sehingga terdapat kelemahan yang dapat mempengaruhi kinerja teknisnya. Oleh karena itu memerlukan penambahan material lain untuk dapat memperbaiki sifat material RAP. Penambahan zat aditif mampu memperbaiki sifat RAP terutama dari sisi kelemahan aspal RAP pada lapisan aspal beton. Tujuan studi ini adalah memperoleh hasil analisis terhadap sifat fisik dan kimia zat aditif untuk memperbaharui sifat aspal RAP pada lapisan aspal beton . Metode yang digunakan adalah studi literatur dari peneliti terdahulu dan analisis zat aditif terhadap parameter pengujian aspal. Hasil yang diperoleh adalah pemanfaatan zat aditif berpengaruh terhadap nilai penetrasi, daktilitas, viskositas aspal. Penambahan zat aditif pada RAP dapat meningkatkan nilai penetrasi aspal RAP dan mengurangi viskositas, sehingga mengurangi getas pada aspal RAP dan meningkatkan kinerja campuran aspal beton. Zat aditif NR aman dan layak digunakan untuk aditif pada perkerasan jalan dengan RAP.

The evaluation of the pull-out experimental result of the steel reinforcing bar on fly ash-based geopolymer concrete prism is presented in this study. A single reinforcing bar with the nominal diameter (db) of 13mm was pulled out from the geopolymer concrete prism. Three sizes of geopolymer concrete prism were presented, 100×100×200, 150×150×200, and 180×180×200 m3. Hence the ratio of cover thickness to diameter of the bar (c/db) were 3.4, 5.4, and 6.6. The effects of embedment length (Ld) that were 3db, 5db, and 7db were investigated. The results showed that the embedment length changed the mode of failure. The pull-out failure occurred on the specimens with the short embedment length (3db), splitting failure occurred on the long embedment length, and the bar ruptured on the large specimens with longer embedment length (7db). The highest of maximum pull-out load and the bond strength obtained were 77.58 kN and 42.13 MPa, respectively. The maximum pull-out load increased with increasing the embedment length. The bond strength decreased as the embedment length increased.

Cracks are caused by many factors. Shrinkage and external loading are the most common reason. It becomes a problem when the ingression of aggressive and harmful substance penetrates to the concrete gap. This problem reduces the durability of the structures. It is well known that self – healing of cracks significantly improves the durability of the concrete structure. This paper presents self-healing cracks of cement paste containing bentonite associated with ground granulated blast furnace slag. The self-healing properties were evaluated with four parameters: crack width on the surface, crack depth, tensile strength recovery, and flexural recovery. In combination with microscopic observation, a healing process over time is also performed. The results show that bentonite improves the healing properties, in terms of surface crack width and crack depth. On the other hand, GGBFS could also improve the healing process, in terms of crack depth, direst tensile recovery, and flexural stiffness recovery. Carbonation reaction is believed as the main mechanism, which contributes the self-healing process as well as the continuous hydration progress.

The practical application of geopolymer concrete structure is getting attention due to its environmentally friendly characteristics. This paper presents non-linear Finite Element Analysis (FEA) on the element size effect in reinforced geopolymer concrete beam. Element size significantly influences the failure mechanism of structure especially in ductile fracture of reinforced concrete. The critical failure strain, crack patterns and orientations are mesh sensitive in finite element analysis for reinforced concrete structure. The impact of the element size on behavioral aspects of reinforced geopolymer concrete beam such as the crack pattern, ultimate load capacity and load-displacement behavior studies discussed along with a formerly conducted experimental data. Further validation of FEA is carried out using the theoretical flexural strength of the beam according to Euro code 2. Results show that element size has a significant effect in capturing the cracking pattern of reinforced geopolymer concrete beam. FEA result from the positive principal strain contour confirms that the fine mesh size captured the tension, the diagonal shear and compression cracks, even the band of surrounding cracks around the bottom reinforcement, precisely as compared to coarse meshes. It has been observed that the utilization of fine mesh with 10 mm element size predicts the experimental and theoretical ultimate load by 99.46% and 96.11%, respectively. Coarse mesh having 25 mm element size shows slightly higher variation in predicting the experimental and theoretical ultimate load by 93.75% and 90.42%, respectively. In addition, fine mesh confirms the experimental mid-span vertical deflection by 99.44% however the coarse mesh predicts in significant deviation by estimating 48.04% of the experimental mid-span vertical deflection. Furthermore, the ductile failure of the beam was accurately traced by the fine mesh.

This paper presents the application of�fly ash�combining with microbes in concrete to reduce cement content.�A class F fly ash as cement replacementwas applied with ratios of 20%, 30%, 40%, and 50% to reduce hydration heat. Microbes from bacterial consortium were applied to as the filler to increase concrete compressive strength. The concrete mix design from SNI 03�2834�2000 was applied for a compressive strength target of 30 MPa. The mechanical test was carried out consisting compressive and tensile test.�Concrete�workability�and the heat hydration measurement were performed for fresh concrete.�The results showed that the maximum strength of 45.10 MPa was obtained from specimens with 30% fly ash content.�Application of microbes associated with�fly ash content of 40% showed the maximum strength of 48.47 MPa.�It was found that the tensile strength also increased with the application of�fly ash�and microbes.�Hydration temperature of concrete decreased with the increase of�the ash�content.�This proves that the application of�fly ash�and microbes in concrete can reduce the cement as well as increasing the concrete performance.

Retrofitting methods are widely used to reinforce existing concrete structures and frames. Strengthening becomes necessary when building codes mandate a higher load carrying capacity originated from, for example, changes in earthquake zone mapping. A haunch conclusively relocates the formation of plastic hinges away from the beam-column-joint. Geopolymer concrete is an environmentally friendly material, based on fly ash. Utilizing a haunch with this material is effectual and sustainable. The low workability of geopolymer concrete was in this study improved by adding a superplasticizer, which effectiveness was trigger by the presence of low volume Portland cement and water creating a Self-Compacting-Geopolymer-Concrete (SCGC). This SCGC ensured easy fabrication in the field, and improved the compaction and homogeneousness of the haunch. A full-scale experiment based on water-loading was conducted on an existing building to analyze the behavior of a SCGC haunch. The research concluded that the SCGC resulted in a high-performance haunch with good compatibility to the structure, the integrity of the haunch and the structure was maintained up to working-loading conditions. The load carrying capacity and the serviceability greatly improved. Analytical comparison to the prismatic section showed that the SCGC haunch reduced the deflection at mid-span to 77%.

This paper presents mechanical properties of geopolymer mortar with metakaolin as a base material. Cylindrical specimens were prepared with a diameter of 5 cm and 10 cm height. Four compositions of geopolymer paste varied with adding polyvinyl alcohol fiber (PVA) from 0% to 1% by volume of paste. After casting, steam curing method was conducted at 40 o C, 60 o C and 80 o C for 24 hours. A control specimen was cured at room temperature. Some tests were performed for setting time, compressive strength, split-tensile, direct-tensile and porosity. It showed that the strength of fibrous specimens was 67.29 MPa at of 56 days without steam curing. When curing temperature was risen from room temperature 80 o C, the strength increased up to 14% at 28 days. Ratio of split to compressive strength was about 10% when 1% fiber was applied. However, an optimum result was shown by specimens containing 0.6% fibers according to direct-tensile test. It is recommended to apply steam curing at 60 o C-80 o C to increase the tensile strength.

The drying cycle can affect embankments based ontheir physical properties and induce soil cracks. This paper investigates the unsaturated physical behavior of material from flood embankments located at the Bengawan Solo River, Pelangwot village, Bojonegoro, East Java, Indonesia. The volumetric shrinkage and degree of compactedness of the soil are important factors that control the soil behavior due to dry conditions. Some tests were conducted to study the desiccation process, in which soil samples were placed in a circular desiccation plate with soil thickness of 10 mm and a 100 mm plate diameter. A water retention curve was obtained to analyze the material properties during shrinkage. Next, the effect of the drying process on geometric characteristics of crack patterns was analyzed by image processing. Then, photo records of cracked soil from laboratory tests were assessed to determine the soil crack intensity via a Fuzzy C-Means (FCM) method using MATLAB software. The image analysis results show that the geometric characteristics of crack patterns were influenced by the drying process with a decrease in water content at 10% intervals until the air-dried condition was achieved. This is consistent with field observations; this indicates that image processing can be used quantitatively to analyze the drying process dependency of soil cracking behavior.

Special structure prone to explosion requires special material. Identification of special material is required to find the right concrete properties. Researching material behavior using explosion test is costly. Therefore, prediction using simulation is needed. In this study, we use ANSYS Workbench as a simulation program. The explosion test model comprised a non-reinforced slab 500×500×50 mm and TNT cube. It was found that the compressive strength minimum of the concrete slab that withstand the explosion of 30 grams TNT was 20 MPa. The Young modulus affects to the concrete behavior using default RHT Concrete properties. It had instability against modified concrete properties when performing numerical analysis.

One of the assets of land transportation infrastructure that obtained attention now is the road. Road construction can support the developing economy, industry, trade, people and good mobility, regional development. Management of road infrastructure assets require to prioritize natural resources managements efficiently as possible. Reclaimed Asphalt Pavement (RAP) is the result of dredging material with aggregate gradation condition that are not in accordance with the needs of the gradation envelope. Utilization of RAP as a pavement layer is an effort to converse the use of natural materials. The efficiency aspect of RAP aggregate use needs to be done by determining the road pavement layer that is most appropriate to the condition of the RAP aggregate so that the addition of new aggregates is kept to a minimum. The aim of this study was to obtain a suitable pavement layer determination based on the aggregate gradation of RAP and standard specifications. The method used literature study from previous research and RAP aggregate sieve analysis from national roads in East Java Province. The results showed that the utilization of RAP from national roads based on the RAP aggregate conformance value were AC-WC layer of 82.292%, AC-BC layer of 68.75% and AC-Base layer of 41.667%. Based on the gradation analysis, it is found that the RAP aggregate is best suited for the AC-WC layer, because it requires optimal RAP aggregate and the most efficient of additional aggregate.

This paper presents the effect of the reinforcing bar diameter (db) and concrete cover thickness to reinforcing bar diameter ratio (c/db) to the bond strength between reinforcing bar and geopolymer concrete by using the experimental pull-out test. The mass ratio of sodium hydroxide (NaOH) to sodium silicate (Na2SiO3) was 2.5 with an 8 M concentration of sodium hydroxide were used in this research. Class F fly ash from Suralaya Power Station, Banten, Indonesia was used as raw material to produce geopolymer concrete. The maximum diameter of coarse aggregate was 10 mm. The result indicated that the maximum pull-out load on reinforcing bar diameter of 16 mm was higher than the diameter of 13 mm. The pull-out failure occurred on the ratio of c/db more than equal of 4.3. The bond strength increased as the ratio of c/db increased, up to 4.3. However, more than 4.3 was the insignificant effect.

Geopolymers have currently drawn great attention of scientists and engineers, mostly in the construction sector. The superior properties of geopolymer and waste valorization are the main factors of the application. To improve the workability and easiness application, a dry activator was implemented to produce a green and sustainable geopolymer. Dry activator was produced by calcining the mix of sodium hydroxide and either unwashed or washed geothermal sludge at a specified temperature. The dry activator was mixed with fly ash to produce the green geopolymer mortar. The compressive strength of the mortar was analyzed accordingly. Thus, the compressive strength as the response variable was processed with Research Surface Methodology (RSM) using minitab® 19. Meanwhile, the independent variables were the activator ratio (Na2O/SiO2) and the calcination temperature 400, 500, and 650 °C. The optimum condition has been reached by using washed geothermal sludge calcined at 400 °C with a Na2O/SiO2 ratio of 0.692 with 27.5 MPa of compressive strength. A more economical and sustainable green geopolymer is the concern of geopolymer applications nowadays. The green geopolymer produces less Carbon Dioxide compared to ordinary portland cement and geopolymer (concrete and mortar) as much as 31% and 23%.

Semburan Lumpur Sidoarjo (Lusi) masih berlangsung sampai sekarang. Inovasi pemanfaatan Lusi menjadi pilihan alternatife karena belum ada cara untuk menghentikan semburan. Fly ash limbah dari PLTU juga dimanfaatkan untuk dijadikan pasta dengan Lusi sebagai material bauatan berbasis pasta berdasarkan nilai kuat tekan dan keausan. Pembuatan pasta silinder 5 cm x 10 cm untuk diuji kuat tekan pada umur 7, 21, 28 hari, dimana pasta terdiri dari pasta geopolimer dan pasta semen. Lusi terkalsinasi 800 ° C dengan ukuran lolos ayakan 200. Metode moist curing digunakan untuk mejaga benda uji selama masa perawatan sebelum pengujian tekan. Dari hasil pengujian kuat tekan pasta geopolimer Lusi 20% : fly ash 80% dengan molaritas 12 M mempunyai kuat tekan pada umur 28 hari sebesar 33.00 MPa dengan keausan 25.08%. Kuat tekan lebih tinggi pada umur 28 hari didapatkan pada pasta semen, dengan perbandingan Lusi 10% : fly ash 30% : semen 60% dengan water to binder 0.27 sebesar 39.83 MPa dengan keausan 30.60%. Sehingga material Lusi dan fly ash bisa dijadikan material buatan berbasis pasta berdasarkan ASTM C 131-03.

This present study analyzed the effect of Rhizopus oligosporus and Sporosarcina pasteurii addition on the properties and surface morphology of fly ash-based geopolymer paste mixtures as a green sustainable material. The addition of bottom ash and a foaming agent were also conducted to improve the paste quality. Compressive strength, porosity, X-Ray Diffractometry (XRD) and Scanning Electron Microscopy (SEM) tests were performed sequentially. The addition of microbes can improve the compressive strength of specimens by up to 43.75%. All microbe-added specimens exhibited a higher amount of closed porosity compared to the non-microbe-added specimens which also responsible to the higher compressive strength. The addition of foaming agent and bottom ash to the mixtures showed a negative effect to the inoculated microbes. SEM analysis showed the initial result of the potential of R. oligosporus and S. pasteurii as a self-healing agent for fly ash-based geopolymer pastes.

Production of ammonia required high capital energy intensive such as high temperatures (400 to 500 °C) and high pressure (15 to 30 MPa). We investigated a new way to produce green ammonia synthesis using new nanocatalyst and operate in room temperature and ambient pressure. The idea is to synthesize ammonia using Magnetic Induction Method (MIM) and Y3Fe5O12 (YIG) as magnetic nanocatalyst. YIG was prepared by sol gel method and sintered at various temperatures 950 °C, 1050 °C, and 1150 °C. X-Ray Diffraction (XRD) result shows that the major peak at [420] plane. The balance composition of YIG resulted by Energy Dispersive X-Ray (EDX) is in the form of Y3Fe5O12. Initial permeability results show, the highest value maximum permeability at 140 with the range of frequency 1Hz to100MHz obtained by 950 °C sample. The lowest value of relative loss factor obtained by 950 °C sample. YIG nanocatalyst and MIM method were successfully produce ammonia yield at 197 μmol, without MIM the yield was decreased by 14.28%.

A caution procedure to use embedded sensor to measure internal RH of low W/C ratio mortars is proposed in this paper. Specimens made from OPC mortar and the one made with 40% BFS replacement cured under a sealed condition at 20°C. The results showed higher internal RH decrement when BFS was applied. The slag content, the creation of the early hydrated products, pore structures of OPC mortars introduced with BFS are considered as the main factors.

Due to environmental pollution form cement industries, some efforts for alternative construction material are increasing. Recently, geopolymer concrete has drawn attention of researchers and engineers because of its lower carbon print and better mechanical property over Portland cement concrete. According to previous studies, geopolymer concrete results almost up to 90% reduction in carbon dioxide (CO2) emission to atmosphere. Mechanical properties of geopolymer concrete such as compressive strength, durability, sulfate resistance, early strength and low shrinkage are better than Portland cement concrete. In addition, the appropriate usage of one ton of fly ash earns one carbon-credit redemption value of about 20 Euros, and hence earned monetary benefits through carbon-credit trade.Therefore, this paper presents a review on the fly ash-based geopolymer concrete. The paper mainly covers composition, mixing and curing process, benefits, limitations and applications of alkali activated fly ash based geopolymer concrete.

This research use metakaolin and clay containing amorphous silica and alumina after calcination at 700°C. Mechanical properties and fire resistance of geopolymer paste increase as the ratio of silica to alumina. Mix design composition on this research based on the ratio of silica to alumina. The ratio of silica to alumina for metakaolin paste are 1.4 and 1.8. While for clay paste the ratio that used are 2.8 and 3.2. Na2SiO3 and NaOH with 10 M and 8 M were used as alkali activator at this research. Based on analysis the effect of increasing the ratio of silica to alumina increase fire resistance ability for both metakaolin and clay. However initial compressive strength is effected not only by ratio of silica to alumina but also the ratio of water to solid and SiO2/Na2O. The compressive strength decrease as the ratio of water to solid increases. Meanwhile compressive strength increase as the ratio of SiO2/Na2O increase.

Oil palm clinker is formed by burning of oil palm kernel shell and fibrous materials in boiler furnace. The clinker is no longer a bio-material that has changed to inert material likes the crushed brick. Large quantities oil palm clinkers have become a waste and caused disposal problem. It requires extra costs for handling, transportation and finding out suitable the dumping site. Research has been conducted to explore the potentiality usage of oil palm clinker as fine and coarse lightweight aggregates at Universiti Pertanian Malaysia. Mixtures of oil palm clinker concretes were designed, prepared and tested. Mechanical properties of a good mixture of tensile strength, compressive strength, modulus of elasticity, creep and shrinkage were satisfied the standard engineering codes of practices. Oil palm clicker concrete was found lighter than conventional concrete, which usually weighs between 2240 and 2400 kg m-3. The means of compressive and tensile strengths were found 30.79 and 3.34 N mm-2 respectively. In addition, the mean of modulus of elasticity was 13.024 kNmm-2. Therefore, oil palm clinker aggregate and concrete are recommended to be used in lightweight reinforced concrete structures.

The effect of loss of ignition, specific gravity, fineness, specific surface area and soluble fly ash to compressive strength of geopolymer paste were studied. Six fly ashes from two different sources and different time of collection were evaluated. Sodium hydroxide and sodium silicate were used as alkali activator. Concentration of sodium hydroxide and mass ratio of sodium hydroxide to sodium silicate were fixed 14M and one respectively. The result indicated that the improvement in compressive strength of geopolymer paste was more influenced by fineness, specific surface area and soluble content of fly ash. Soluble content of fly ash greatly affected the compressive strength of geopolymer paste compare to the compressive strength of cement paste with 20% fly ash replacement.

Light weight buildings are required in Indonesia to reduce the risk due to the earthquakes. Therefore, the presence of lightweight materials are needed. Moreover, fly ash that is a waste of coal combustion process, has a basic ingredient of geopolymer binder. If the geopolymer binder is mixed with a foaming agent, it will be a lightweight geopolymer binder, in which it can be used as wall elements that have light weight. Furthermore, the utilization of fly ash will reduces the pollution due to the release of CO2 during production of Portland cement. Thus the use of fly ash results in environmental safety. This study investigate about fibrous lightweight geopolymer binder, in which the main materials used was fly ash with the alkali activator such as NaOH and Na2SiO3. Foaming agent was used to form micro-pores. Abaca fiber was used as a reinforcement to avoid cracks. Normal curing and steamed curing were utilized at temperature 60°C for 6 hours. Meanwhile, tests conducted were compressive strength, density and porosity. Steam curing method resulted an increase in strength and gives less density even though the same amount of pores was formed.

A research has been conducted to investigate the physico-mechanical and microstructure properties of geopolymers synthesised from metakaolin activated with sodium silicate solution. A wide range of physical and mechanical properties of geopolymers were studied such as bulk density, porosity, Vickers hardness, compressive strength, thermal expansion and thermal conductivity. It was found that these properties were directly related to geopolymers process variables such as Si:Al, Na:Al, Na2O:H2O, time and curing temperature. The structure of the resulting geopolymers was studied by using X-Ray diffraction (XRD) and the microstructure of geopolymers paste and the interfacial transition zone (ITZ) between the aggregate and the matrix of geopolymer were studied by using Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). The results gave a new insight into the composition-microstructure-property relationship of geopolymers and paving the way to the production of geopolymers with improved performance in a variety of applications.

The purpose of this research is to observe the strength of asphalt concrete using solidified coal waste or geopolymer. The use of geopolymer is known in enhancing concrete mixture strength. More detail in this study is to acquire the comparison rate of stability and flow of mixture using geopolymer and the one with ordinary filler. The stability and melting rate of this mixture will determine whether the use of geopolymer as a filler material in flexible pavement is applicable. In this research, the first stage is to find the initial mix design, which is not including the geopolymer filler. From this research, it is found that the use of geopolymer increases the stability in asphalt mixture but reduce the melting rate and increase the cavity in the mixture. Although the melting rate decreases and the voids increases, the result acquired still fulfills the minimum specification of asphalt concrete for the high level of traffic load.

Self-healing cement is a novel topic in concrete technology. Concrete is created to have its own ability to heal cracks. Crack closure is due to the material deposition of the gap so causing the crack closed. Materials used in this paper is mortar composition with ordinary portland cement replaced by calcium carbonate (CaCO3) and rice husk ash. There are three testing presented in this paper. The first is compressive test to determine the compression applied to mortar for initial cracks. The second is an ultrasonic pulse velocity (UPV) test to observe the depth of cracks and density of each composition. The third is macroscopic investigation to observe cracks wide in each mixture. The maximum compressive strength of 22.46 MPa shown by specimens made with 10% rice husk ash and 10% calcium carbonate cement. By the end of healing process, it reached 23.18 MPa. It was also shown that in crack depth decreased from 38 mm to 16 mm. From this analysis, it can be concluded that rice husk ash (RHA) and calcium carbonate (CaCO3) can be utilized as self-healing concrete materials.

Glass powder is known as a reactive material with silica content more than 72% and potentially considered as pozzolanic material. Moreover, it is known that binder containing silica fume 10-26% by weight increases the compressive strength of concrete. A low water to binder ratio is needed to increase the strength. In this paper, materials for making paste were analyzed for X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and reactivity. Composition of paste with the highest strength at 28 days was 93.26 MPa. Glass powders had higher reactivity compared to silica fume. Therefore, the recommended amount of glass powder to increase mechanical properties is 10 – 15% from cement weight and silica fume content are 40 – 60% from glass powder weight. A tendency of strength increasing after 28 days was found. In general, addition of silica fume to glass powder prolonged the initial setting causing the distance between initial and final setting time became closer.

With the advancement of technology and the economic crisis in Malaysia, has been promoting the development of infrastructure in the use of new structural materials but overall is unsatisfactory in terms of cost savings. One of the alternatives that can be used is to use fly ash as a cement replacement in manufacturing mortar. Replacement of cement with geopolymerization mortar can reduce manufacturing costs and could reduce global warming arising from the production of cement for the production of Portland cement for the release of CO2 into the atmosphere, where CO2 gas gives the largest contribution to global warming . The study will be focused on the effect of microwave curing with various durations and temperature to the mechanical and physical properties of fly ash based geopolymer mortar. For the conventional heating technique, heat is distributed in the specimen from the exterior to the interior leading to the non-uniform and long heating period to attain the required temperature. Application of microwave to the fresh concrete results in removal of water, collapse of capillary pore and densification of sample. Heat curing has been applied to construction materials especially for the precast concrete to improve the strength development process. This concrete attains sufficient strength in short curing time, so the molds can be reused, and the final products can be rapidly delivered to the site. The effect of curing temperature together with their aging days of the cured product will also be investigated. Mechanical properties of the product will be tested using compressive test, and density of the samples.

This paper presents the effects of chloride ions on OPC (Ordinary Portland Cement) concrete coated with fly ash-based geopolymer mortar. The coating was applied to protect concrete in coastal areas. The mortar was a mixture of fly ash and alkali activator with a mass ratio of 65:35. The alkali activator was a mixture of Na2SiO3 and NaOH 12M with a mass ratio of 2.5:1. The coating thickness varied at 2.5 cm, 4 cm, and 6 cm. All specimens were exposed to a marine area with seawater curing for 90 days. The mechanical properties of the specimen were determined by compressive strength. Chloride penetration was assessed for durability. A series of tests were carried out after 0, 30, 60, and 90 days of immersion. Compressive strength after a 90-day immersion increased by 34.16%, 39.81% and 31.38% for thickness 2.5 cm, 4 cm, and 6 cm respectively. Compressive strength with a thickness of 4 cm reached 52 MPa, which was the highest strength. The binding capacity of the chloride in geopolymer coatings was more than 80% and could reduce the free chloride content in concrete. Geopolymer mortar coating on OPC concrete showed good results in compressive strength and resistance to chloride attack from sea water. The recommended coating thickness for optimum results suitable for application is 4 cm.

Poorer reactivity of fly ash (FA) than Portland cement brings to the problems of low strength and setting time delays of very high-volume fly ash cement paste. This study combines precipitated-calcium carbonate (PCC) substitution and dilute-alkali fly ash treatment for overcoming those drawbacks. The strength was examined at 3-, 7-, 28- and 56-day. Scanning electron microscopy and Fourier-transform infrared spectroscopy were applied for characterisations. PCC substitution improved the strength and shortened the setting time; then additional dilute-alkali fly ash treatment results in better properties. Combination of PCC substitution and dilute-alkali treatment enhances cement hydration and FA pozzolanic reaction simultaneously.

This study discusses the effect of heating duration and curing age on compressive strength geopolymer paste made with medium calcium fly ash and potassium hydroxide solution (KOH). The hardening process was performed in an oven at a temperature of 100 ± 5°C in a variety of heating duration for 2, 4, and 6 hours to form a geopolymer paste with a potassium hydroxide concentration of 6 M. Flow testing on fresh paste indicatesd that all materials was bond properly without segregation. After the heating process in the oven, the spesimens were cured at room temperature until the age of 3, 7, and 28 days. The results of the compressive tests indicated that the heating duration and curing age were the key factors. Where there is no visible negative effect of the medium level CaO content in fly ash against compressive strength development of the hardened geopolymer paste.

International audience; This study discussed the mechanical properties of natural and metakaolin based geopolymer stabilized soil. The mechanical soil properties is an important soil properties that determine the soil strength parameter and its behaviour. It is proposed to do an assessment on 2 types of soil: natural (remolded) soil and metakaolin based geopolymer (MKG) stabilised soil of Bengawan Solo River Embankment soil. The soil sample are treated on oedometer test in order to know soil compressibility and permeability. The result shows that the implication of MKG for natural (remolded) soil only have an influence in reducing swelling. Also for the permeability, it is found that despite the high porosity (index high vacuum), its permeability is smaller than the permeability of other mixtures.

Jalan raya merupakan salah satu aset infrastruktur yang berperan dalam distribusi barang dan orang, perkembangan wilayah, ekonomi, sosial dan politik. Upaya pemeliharaan jalan dengan pengupasan material perkerasan di Provinsi Jawa Timur menghasilkan Reclaimed Asphalt Pavement (RAP) yang volumenya berkisar 50.000 m 3 /tahun. Upaya pemanfaatan Reclaimed Asphalt Pavement perlu dilakukan semaksimal mungkin sehingga menghasilkan campuran aspal beton yang memenuhi spesifikasi. Tujuan studi ini adalah memperoleh kinerja campuran aspal beton dengan penambahan Reclaimed Asphalt Pavement dan strategi pemanfaatan Reclaimed Asphalt Pavement. Metode yang digunakan adalah studi literatur dari peneliti terdahulu berbahan Reclaimed Asphalt Pavement dari jalan nasional di Provinsi Jawa Timur. Hasil yang diperoleh adalah kinerja teknis campuran dengan Reclaimed Asphalt Pavement memenuhi persyaratan Spesifikasi Bina Marga Tahun 2010 Revisi 3. Reclaimed Asphalt Pavement dapat digunakan pada lapisan AC-WC, AC-BC, AC- Base , dengan persentase penggunaan RAP sebesar 20-40%, RAP optimum sebesar 20-30%, kadar aspal dalam RAP sebesar 3,78-4,63%, VIM sebesar 4-4,825%, VMA sebesar 14,941-15,867%, VFB sebesar 65-87%, Stabilitas Marshall sebesar 830,482-2655,22 kg, flow sebesar 3,26-5,74 mm, Stabilitas Marshall Sisa sebesar 90,1-92,65 kg, VIM in PRD 2,525-5,09%. Strategi pemanfaatan Reclaimed Asphalt Pavement yaitu perlu menambahkan material lain yang baru atau material yang ramah lingkungan untuk digunakan sebagai material perkerasan jalan.

Fly ash is a by-product obtained from coal combustion process. Some of the utilization of fly ash is to produce geopolymer products which have high compressive strength, fire, chemical resistance. This paper proposes fly ash from unit 1-7 Suralaya Power Plant Indonesia. The aims of this study are to obtain characterization of fly ash and mechanical properties of geopolymer paste based on variations of the alkali activator ratio. The method was based on previous research and laboratory investigation. XRF and compressive strength were analysed in this study. Alkali activator was obtained from NaOH and Na2SiO3 mixture. The ratio of Na2SiO3 to NaOH was in the range of 0.5-2.5. Geopolymer paste was casted in acrylic cylinders with a diameter of 2 cm and a height of 4 cm. The curing was conducted at room temperature until the day for the compressive strength test at 28 days. The result showed that the fly ash is classified as F class. Increasing the alkali activator ratio influenced the strength. The best composition of geopolymer paste is made with NaOH 8M, and the mass ratio of Na2SiO3 to NaOH is 2.5. This composition produced compressive strength of 98.6 MPa.