Shellac dan Gelatin untuk Konsolidasi Artefak Kayu

Wood is a hygroscopic organic material, prone to damage and weathering, especially by humidity. The moisture in the wood will trigger biotic activities such as fungus, which can decompose of wood materials, that is, cellulose. Moreover, wood is susceptible to insect attacks such as termites. This condition will cause the wood to become brittle so that the strength of the wood will decrease. To strengthen brittle wood, consolidation treatments are needed. Material for wood consolidation that has been used is Paraloid B72 with acetone solvent, which is not easy to find everywhere Materials tested for wood artifacts consolidations were shellac and gelatin with a concentration of 5%, 7,5%, and 10%. As a comparison, the material used for wood consolidation is Paraloid B72 10%. Test parameters used include SEM test, density test, compressive strength test, color change test, fungal growth observation, and FTIR test. Test results have shown that shellac 7,5% and 10% can be an alternative to Paraloid B72 as a wood artifacts consolidation material. Shellac 7,5% is the optimum concentration for wood artifacts consolidation because materials will be more efficient. This material can fill the wood pores and increase the density by 13,89%. The resulting compressive strength value reached 248,01 kg/cm2 or increased by 43,18%, higher than Paraloid B72 10%. Shellac 7,5% does not change the color of the wood and safe from fungal growth when applied to wood. This material also does not change the chemical composition of wood. Keywords: wood, artifact, consolidation, shellac, gelatin, Paraloid B72

The Use of Crude Coconut Oil (CCO) as an Alternative Oil Base Mud (OBM) for Drilling Operations by "VICOIL" Standard Drilling Simulation Rig

Shale is one of the rocks that often causes drilling problems because shale tends to swell or swell when in contact with mud filtrate, mainly water-based or Water-base Mud (WBM). This study aims to determine how the performance of Oil-base Mud (OBM) based on Crude Coconut Oil (CCO) in overcoming the swelling problem. The methodology used consists of drilling simulation and cutting analysis in the X-Ray Diffraction (XRD) laboratory. The series of activities in the study began with the preparation of rock layers, followed by testing the penetration rate using Water-base Mud as a comparison. After cutting analysis was carried out in the XRD laboratory of UPN "Veteran" Yogyakarta with the Rigaku tool, then replaced the type of drilling fluid Oil-base Mud with basic materials alternative to Crude Coconut Oil (CCO) and followed by a penetration test. Rate of Penetration (ROP) test results from WBM with Rheology 1 at interval depth of 1.64 ft-3.28 ft is 442.8 ft/h, Rheology 2 at interval depth of 4.92-6.5 ft is 118.5 ft/hr on the first day. Swelling occurred and results in pipe sticking at depth of 3.28 and 6.5 ft. Based on the Bulk Mineral analysis, clay mineral content is 23.84%. Based on the Clay Oriented, smectite dominates the clay by 29.09%. Based on MBT, shale belongs to class B (illite and mixed-layer montmorillonite illite), where this mineral can expand. Based on a Geonor As test, 5.18% of the cutting can develop when exposed to water. The drilling fluid was replaced with Oil-base Mud based on alternative Crude Coconut Oil (CCO), and obtained ROP Rheology 1 at Interval depth of 3.28 ft-4.92 ft is 492 ft/h and Rheology 2 at Interval depth of 6.5 ft-10.5 ft is 480 ft/h. The results of the Compressive Strength test interval A on the first, third, and fifth days were 31,699 psi, 42,265 psi, and 52,831 psi. The results of the Compressive Strength test interval B on the first, second, and third days were 31,496 psi, 41,517 psi, and 52,971 psi. Based on clay mineral analysis and magnitude of ROP value, is known that Crude Coconut Oil (CCO) based Oil-base Mud is effective because during the simulation, there are no drilling problems, and the resulting ROP value is greater than the first day Water-base Mud.

THE EFFECT OF ADDING CEMENT WASTE ON THE QUALITY OF CONCRETE COMPRESSIVE

Infrastructure development is one of the important aspects of the progress of a country where most of the constituents of infrastructure are concrete. The most important constituent of concrete is cement because its function is to bind other concrete materials so that it can form a hard mass. The large number of developments using cement as a building material will leave quite a lot of cement bags.In this study, the authors conducted research on the effect of adding cement waste to the compressive strength of concrete. This study used an experimental method with a total of 24 test objects. The test object is in the form of a concrete cylinder with a diameter of 15 cm and a height of 30 cm and uses variations in the composition of the addition of cement waste cement as a substitute for fine aggregate, namely 0%, 2%, 4% and 6%. K200). The compressive strength test was carried out at the age of 7 days and 28 days.The test results show that the use of waste as a partial substitute for fine aggregate results in a decrease in the compressive strength of each mixture. at the age of 7 days the variation of 2% is 16.84 MPa, 4% is 11.32 MPa and for a mixture of 6% is 6.68 MPa. Meanwhile, the compressive strength test value of 28 days old concrete in each mixture decreased by ± 6 MPa. So the conclusion is cement cement waste cannot be used as a substitute for fine aggregate in fc 16.6 (K200) quality concrete because the value is lower than the specified minimum of 16.6 MPa.

Experimental Investigation of Ultrasonic Pulse Velocity (UPV) Test Specimen in Assessing the Strength of Steel Fiber Reinforced Concrete Structure

This study aims to conduct the Ultrasonic Pulse Velocity (UPV) test and compressive strength test of Steel Fiber Reinforced Concrete (SFRC). This paper also examines the correlation of UPV test data and compressive strength test data for SFRC specimens. The experiments were carried out with the same value of the water-cement ratio, superplasticizer but different fiber volumes of steel fiber. Twelve prism sizes 100mm x 100mm x 500mm were casted and 0.5%, 1.0%, and 1.5% of steel fiber reinforced concrete were added and the prisms undergone curing for 7, 14 and 28 days. The highest value of the UPV test at the x-axis is SFRC-0.5%, 6.26 km/s at seven days and 6.8377 km/s at 14 days. The highest value of the UPV test at the y-axis is SFR-0.5%, 6.68 km/s at seven days and 6.34 km/s at 28 days. Nevertheless, the grading is still considered excellent concrete quality based on BS1881. The highest value of compressive strength is SFRC-1.0%, 193.2 MPa at 14 days. The R-squared value for the correlation coefficient between UPV result and the compressive strength result at the x-axis and y-axis is 0.9963 and 0.9966 respectively. The non-linear models show high regression coefficient of R-squared close to 1.00, which means the parameters are strongly correlated. The correlation equation obtained can be used to predict compressive strength based on UPV data for steel fiber volume fraction up to 1.5%. Thus, it can be concluded that percentage of steel fiber added, affect the strength of the tested concrete specimens and the optimized value of steel fiber added is at 1% in this study.

Optimization of Additional Composition Variations ZnO Nanoparticles on The Characteristics of Porous Hydroxypatite as Bone Filler

Research on the synthesis and characterization of porous hydroxyapatite with the addition of ZnO nanoparticles has been carried out through a combination of foam immersion and injection methods. This research was conducted to optimize the previous research by increasing the variation of ZnO composition and adding the injection method to the research process. The materials used in this research include hydroxyapatite nanoparticles, ZnO nanoparticles, Aquades, PVA and polyurethane foam. Manufacturing is done by immersing polyurethane foam into a slurry. Slurry is a mixture of PVA and hydroxyapatite solutions with variations in the addition of ZnO nanoparticles (8 wt%, 10 wt%, 12 wt%, and 14 wt%). Then inject the remaining slurry into the foam. After that the sample was dried and heated at a temperature of 650ºC to remove foam and PVA, then the sample was sintered at a temperature of 1200ºC for 3 hours. Based on SEM analysis, porosity test, and compressive strength test, the best results were shown by sample IV because it had a pore diameter of 142.9 – 371.4 m with a porosity of 69.983%, a compressive strength value of 1.8653 MPa and non-toxic. The best results have not met the standard for bone filler application. In further research, improvements need to be made by using other additives such as ZrO2, so that it can improve the mechanical properties of porous hydroxyapatite to meet standard bone filler applications.

Use of Biopolymers in the Stabilization of Clay Soils

The treatment and stabilization of soils make it possible to recycle materials on construction sites in preparation for the installation of a final covering or the construction of a road network. In road geotechnics, various materials such as lime, cement, and pozzolans were used as additions to stabilize clay soils. In recent years, bio-polymers and bacteria are of increasing interest to researchers in the field of stabilization and improvement of the physico-mechanical and chemical characteristics of clay soils. Currently, in place of traditional clay treatment techniques and to minimize environmental problems, natural fibrous waste is being used increasingly and spectacularly. Several studies on biotechnological engineering applications already exist, such as the use of vegetation, algae, bacteria, enzymes, and biopolymers. The northern Algerian region where the urban tissue does not stop expanding contains significant potential in terms of wheat straw, which represents a very present agricultural waste. So, there is a local interest in the sustainable development of several regions known to produce wheat. This study is interested in investigating the effect of wheat straw on the stabilization of swelling clay soil. In order to improve the physico-mechanical characteristics of clay soils, a series of laboratory tests (Atterberg limit, Proctor test, direct shear test, Oedometer test, and unconfident compressive strength test) were carried out on reconstituted clay soil with defined initial properties through numerous analyses (e.g., XRD and XRF) and then treated with different vegetable fiber content. The results indicate that there is an improvement in the compressibility characteristics of the treated soil, a remarkable decrease in the swelling index and the compressibility index respectively with increasing percentages of wheat straw.

Mass Concrete Placement of the Offshore Wind Turbine Foundation: A Statistical Approach to Optimize the Use of Fly Ash and Silica Fume

The experimental program investigated concrete with a large amount of fly ash (FA) with silica fume (SF) to replace Portland cement on the results of semi-adiabatic test, compressive strength test, and the rapid chloride permeability test (RCPT). The replacement ratios of cement by a combination of FA and SF were 30%, 35%, and 40% by mass. The percentages of SF to replace cement were 0%, 4%, and 8% by mass. Three different water-to-binder ratios (W/B) of 0.34, 0.36, and 0.38 were also investigated. Multiple linear regression was applied to construct the predicted equations (models) for the semi-adiabatic temperature rise test and the compressive strength test. Models were assessed statistically and were used to solve the concrete mixture design optimization problems. The mixture with W/B of 0.36, 31% FA, and 5% SF was found to optimally satisfy the multi-objective problem: 28-day compressive strength of 50 MPa, low heat of hydration, and very low chloride penetrability classification. Field test on the actual wind turbine foundation of the optimal mixture revealed the maximum temperature rise was 74.8 °C and the maximum temperature differential was 21.9 °C.

Natural Fluorite from Órgiva Deposit (Spain). A Study of Its Pozzolanic and Mechanical Properties

This work presents the results of the partial substitution of Portland cement (PC) by natural fluorite (NF) and calcined fluorite (CF) in mortars, at 10%, 25% and 40%. To meet these objectives, a sample of fluorite was initially studied by XRD, SEM and Raman Spectroscopy (RS). A chemical quality analysis (CQA) and a chemical pozzolanicity test (CPT) at 8 and 15 days were carried out in a second stage to establish the pozzolanic properties of the investigated sample. Finally, a mechanical compressive strength test (MCST) at 7, 28 and 90 days was carried out on specimens made up with PC/NF and PC/CF mixes, at a ratio of 10%, 25% and 40%. XRD, SEM and RS results indicated fluorite as the major mineralogical phase. The CPT and CQA showed an increase in the pozzolanicity of the samples from 8 to 15 days. The MCST showed an increase in compressive strength from 7 to 90 days for both PC/NF and PC/CF specimens. The results obtained establish that fluorite produces positive effects in the mortar and contributes to the gain of mechanical strength over time, being a suitable material for the manufacture of cements with pozzolanic addition with a reduction of CO2 emissions, and by reducing the energy costs of production.

Influence and Possibility of Using Limestone Dust Replacement of Sand for Sustainability in Concrete Production

This paper aimed to assess the potential of using limestone dust to replace sand at levels of 0, 20, 40, 60, 80 and 100% by weight. Concrete mix design for cement : fine aggregate : coarse aggregate was 1: 2 : 4 and 0.40, 0.50, 0.60 water-to-cement ratios were used. The study started by testing the basic properties of the material. The compressive strength test was done with curing for 7, 14, 21 and 28 days and modulus of elasticity of concrete at 28 days, after which the microstructural properties of concrete modified with limestone dust were investigated. The study found that the concrete had better workability when increasing the limestone dust content. The incorporation of 40% limestone dust at 0.50 water-to-cement ratios was found to improve the compressive strength of the concrete and resulted in the maximum compressive strength. However, high levels of replacement lead to porous microstructures. Moreover, the use of limestone dust in concrete production tends to be more cost-effective. Therefore, the results of this research seemingly provide confirmation and support for the utilization of these waste materials by reducing the use of natural resources. Further, it is a goal of local governments to help promote the value of limestone dust for future use.