ASTM Test Method Research Articles

Comparing low frequency impact insulation measured with the rubber ball versus the tapping machine

The heavy/soft impact source or rubber ball, defined in ISO 10140 and 16283, is used primarily in Japan and Korea to evaluate low-frequency impact insulation from sources such as walking without shoes and children jumping. ASTM test methods currently do not include the heavy/soft source, and low frequency impact noise insulation is currently measured with the tapping machine using ratings such as LIR and LIIC per ASTM E3207. ISO ratings using spectrum adaptation terms from 50 Hz or lower can also be used. The relationship between these ratings and those measured using the heavy/soft source has not been well characterized for assemblies that are common in North America. The authors present field and laboratory data of impact insulation with both sources. Analysis of the data describes the relationship between the sources, the information they provide to the designers of floor assemblies, and implications for classifications of low frequency impact insulation.

Comparing impact insulation measured with the rubber ball versus the tapping machine

ASTM test methods for measuring impact noise insulation use a standard tapping machine, which generates impact noise by dropping steel hammers on the floor surface. An alternative source is the heavy/soft impact source or rubber ball, which is defined in ISO 10140. The heavy/soft source was developed in Japan to correlate with sources such as walking without shoes and children jumping. Compared to the tapping machine, it generates elevated noise levels at low frequencies and generally negligible noise above about 500 Hz. The relationship between low frequency impact noise insulation measured with the tapping machine, such as LIIC, and with the heavy/soft source has not been well characterized for assemblies that are common in North America. The authors present field and laboratory data of impact insulation with both sources, and analyze the data to describe the relationship between the sources and what information they provide to the designers of floor assemblies.

Investigation and comparison of insulating oil properties using various analytical methods

ABSTRACT In the current scenario, rising energy consumption has put a significant burden on transformers. Simultaneously, power utility companies are reducing their capital investments. As a result, industrial consumers are increasingly focused on maintaining the trouble-free operation of their existing transformers to ensure their reliability remains intact. The reliability of the transformer heavily counts on the health and condition of its insulating oil and the various physicochemical and dielectric properties associated with it. Various national and international organisations, such as ASTM, IEC, and IS (Indian Standard), have established standardised test methods to evaluate the insulating oil properties. These tests help in assessing the oil’s quality and the transformer’s condition. Monitoring the properties of insulating oil using established test methods is vital for assuring transformer reliability. It allows for early detection of potential issues and enables timely maintenance or replacement actions to prevent costly failures. This paper aims to analyse and compare the key properties of mineral insulating oil including breakdown voltage (BDV), water content, IFT, and acidity, utilising ASTM, IEC, and IS standard test methods to assess the accuracy and uniformity of the test method. The results serve as a valuable resource for analysts and professionals.

Synthesis of polyesters derived from glycerol and phthalic anhydride and its application for bitumen modification

AbstractThis study introduces phthalic anhydride (P) and glycerol (G)‐based polyester as an additive for upgrading lower‐grade bitumen to higher‐grade bitumen. The different colorless polyesters were synthesized using polycondensation of P and G as a monomer in the ratio of 1:1 and polymerization time of 1, 3, 5, and 7 h. A rheological analysis was performed on all the synthesized polyesters to check their performance with respect to their use in bitumen modification. The polyesters were blended with base bitumens (VG10) to obtain the modified bitumens that were tested for the rheological and physicochemical properties and to assess the performance based on the grade quality test. The quality test of the modified bitumens includes softening point (SP), penetration (PEN), kinematic viscosity (KV), dynamic viscosity (DV), and rheological properties as per standard ASTM test methods. Based on the performance evaluation, P1G1H3 polyester was found suitable for blending with bitumen, and further study was carried out with blending of P1G1H3 with 3, 6, 10, and 15 wt%. The finding illustrates that 6.0 wt% of polyester‐modified bitumen show an enhanced SP, KV, and DV by 23.6, 86, and 30%, respectively, while decreasing the PEN by 49% with respect to VG10. Polyester blending also improved the rheological parameters in terms of deformation resistance, load‐bearing capacity, and the viscoelastic nature of bitumen. The investigation concluded that 6 wt% P1G1H3 polyester on blending in VG10 meets VG30 bitumen specification as per IS:73:2013.

Cost, Emission, and Thermo-Physical Determination of Heterogeneous Biodiesel from Palm Kernel Shell Oil: Optimization of Tropical Egg Shell Catalyst

The advantages of reusability, lower cost, and environmentally friendly operation have made the heterogeneous catalyzed methylic process a preferable alternative to the homogeneously catalyzed protocol. The optimal production yield of palm kernel shell oil (PKSO) methyl ester (PKSOME) was modeled using Response Surface Methodology (RSM). The cost of PKSOME was determined, and the synthesized PKSOME was blended with diesel fuel with various volume ratios. Several analyses were done, including thermophysical properties using ASTM test methods, density and viscosity, fire point and flash point, aniline point, and acid value. Emission characteristics such as exhaust smoke, carbon monoxide, and carbon dioxide were measured using an IC engine. The use of waste eggshells for heterogeneously catalyzed biodiesel from underutilized PKSO for green diesel can reduce production costs even further. The green biodiesel model and TP correlations have applications in the biodiesel and aviation industries.

Rheological and tribological behaviour of nanofluids: an experimental evaluation

Commercially available synthetic engine oils of SAE grades 5W40 were taken as base fluids for preparing nano fluids by blending 0.1% and 0.2% concentration by weight of the functionalized Cu and MoS2 nanoparticles in them. The base fluids and their blends were characterized using standard ASTM and IS testing methods for their physicochemical and tribo performance behaviours. The rheological studies were performed on a Rheometer while the tribological investigations were performed on tribo-tester. The study reveal that a small improvement in anti- friction behaviour of about 6% and 4% reported for the 0.2 wt% of Cu and MoS2 nanoparticles respectively in the tested lubricants indicate that finished products have little scope to improve anti-friction properties under the influence of already present additives, however anti-wear properties showed significant enhancement up to 20% for 0.2% MoS2 and up to 15% for 0.2% nano-Cu indicating better anti-wear properties of MoS2 and Cu nanoparticle blends. Rheological studies reveal that blending of nanoparticles has marginal influence on the rheological behaviour of the lubricants. The lubricants show shear thinning behaviour at low shear rates. However at higher shear rates, lubricants behave as Newtonian fluids.

Asymmetric Four Point Bend Test Method for Interlaminar Shear Strength in Ceramic Matrix Composites

Asymmetrical Four Point Bend test method is proposed for measurement of interlaminar shear strength in continuous fiber reinforced ceramic composites. The current standard ASTM test method (ASTM C1425) for interlaminar shear strength of composites uses a double edge notched compression (DNC) coupon. Large variation in measured strength is observed with the standard ASTM test method, possibly due to machining variability and damage at the notches. The proposed test AFPB method for ILSS is adapted from ASTM C1469 Standard Test Method for Shear Strength of Joints of Advanced Ceramics. This test method does not require any machining of notches and the sample size requirement is much smaller than the ASTM test method. The shear loading in this method is similar to the standard short beam shear test (ASTM D2344) with higher shear to tensile ratio compared to SBS with AFBP. Using finite element analysis, coupon geometry and the distance between the loading and support pins was optimized to maximize shear and minimize tensile and compressive stresses on the specimen. It was found that the variability in the measured ILSS strength was lower with this method compared to the ASTM standard method using the DNC specimen. In addition, the value of ILSS measured using AFPB method was found to be consistently higher than that measured using DNC coupons. It was also found that specimen preparation (cutting, polishing, etc.) did not have significant effect on the measured strength.

A comprehensive study for physical and chemical properties of road dust to utilize in concrete mix design, collected from diversified locations of Delhi NCR

Rising volume of road dust is a serious concern in global as well as Indian scenario. To find out the possible application, chemical and physical characterizations of road dust of six diversified sites of Delhi, National Capital Region, India were carried out prior to utilize in concrete mix design. The chemical characterizations suggest major and minor components are oxides of silicon, aluminium, iron, sodium, calcium, potassium, sulphur, phosphorous, manganese etc. X-ray diffraction studies depicted major phases of silica, muscovite/ illite, K-Feldspar and albite minerals. Scanning Electron Microscopy studies depicted flacks, fibrous, spherical, irregular, voids and hexagonal morphologies. Further detailed studies of road dust of two sites were carried out in concrete mix design following IS and ASTM test methods to know the effects on compressive strength, flexural strength, water and rapid chloride permeability test after replacing upto 50% of stone sand by road dust. The 7th and 28th days compressive strength test results of two sites concrete showed 16.51%, 8.25% and 4.67%, 2.34 % lesser strength in comparison to control concrete respectively. Similarly, 7th and 28th days flexural strength studies of same sites concrete showed 19.67%, 14.75% and 6.85%, 1.37% lesser strength in comparison to control concrete, respectively. The depth of water penetration test results of two selected sites of concrete showed 13.14% and 10.22% lesser extent of water penetration under 5 bars hydrostatic pressure, when compared to control concrete. The RCPT results of same sites concrete showed 33.47% and 9.48% greater extent of chloride ion permeability, in comparison to control concrete. The results obtained after 7th and 28th days of conventional stone sand concrete and road dust concrete, showed quite comparable results. However, in case of water permeability test the road dust concrete showed lesser extent of water percolation in comparison to conventional concrete, this may be due to presence of more fines in road dust, which may have caused better packing and lesser voids for water to ingress.

Parameter optimization for enhanced biodiesel yield from Linum usitatissimum oil through solar energy assistance

Biodiesel is a biofuel produced from vegetable oils and animal fats. The study describes the solar-assisted biodiesel production from linseed oil and the parameter optimization using Taguchi’s L27 orthogonal approach and response surface methodology (RSM). A solar paraboloid dish of collector area 6.1 m2 and concentration ratio approx. 200 is used for the transesterification process. Yearly and daily solar radiation data shows that May–June has more extended solar radiation availability during the daytime and are favorable months for experimentation. Results show that Taguchi’s approach gives a maximum biodiesel yield of 89.14%, while the RSM model offers a slightly higher 91.9% yield. However, the RSM analysis predicted 91.1% (maximum biodiesel yield) at molar ratio (MR) 8.92:1, reaction time (RT) 108.97 min, and catalyst concentration (CC) 0.61 wt%, respectively. ANOVA analysis found that the MR has the highest percentage contribution of 75.67%, followed by CC (15.9%) and RT (5.69%). Biodiesel composition is determined using gas chromatography and FTIR analysis, and the various other fuel properties are measured as per ASTM testing methods. The study successfully confirms the use of solar heating for the transesterification process.

Development of Next Generation EV Coolant

Research indicates that there are two approaches to Electric Vehicle (EV) liquid cooling: direct and indirect. Direct liquid cooling involves direct contact between the coolant and the battery pack. Indirect liquid cooling requires a medium in between the battery pack and the coolant, preventing direct contact. Many prominent EV manufacturers have adopted indirect liquid cooling for example Tesla, and GM in North America. Currently, shelf coolants used for Internal Combustion Engines (ICE) are being used in many EV vehicles for indirect cooling. One of the challenges is absence of ASTM test methods for evaluating EV coolants. Some operators have used copper wires for generating deposits by employing voltage to test low conductivity EV coolants. Dober long ago realized that copper and aluminum will be the main components of EV engines hence used copper wire under high temp and pressure to show differentiation among coolants. The present paper focuses on Dober-in-house test Parr reactor methodology for comparing electrical conductivities, pH and additive depletion of various coolants thereby showing meaningful trends with time and temperature. This ultimately helps in developing new generation EV coolants. It is concluded that low electrical conductivity along with robust corrosion inhibition package is needed for optimum performance of EV coolants.

Environment-Induced Cracking of High-Strength Al-Zn-Mg-Cu Aluminum Alloys: Past, Present, and Future

Environment-induced cracking (EIC) during commercial use of aluminum alloys started over 125 y ago (mid-1890s), some 45 y earlier than previously documented, with earliest failures for Al-Zn-Mg-Cu, 7xxx series alloys occurring a decade later. Needs for lighter, thicker, and stronger alloy products, first driven by WW1 and WW2 militaristic requirements and subsequently by relentless demands from modern aircraft industry designers, resulted in major in-service EIC in commercial high-strength Al-Zn-Mg-Cu alloys in the United States and United Kingdom during the 1950s, 1960s, and 1970s. These were avoidable had research findings from France, Germany, and Japan from the 1930s and 1940s been implemented. Unprecedented U.S. Government R&D funding during the late 1960s, 1970s, and early 1980s led to AA7050 and similar alloys, that essentially eliminated EIC issues during commercial usage for several decades. EIC assessment for the following “new-generation” high-strength alloys relied totally on standard ASTM test methods, incapable of providing data directly relatable to the service conditions. Although EIC service issues for the latest generation of 7xxx series alloys remains manageable, the premature appearance of EIC requires a quantitative understanding of EIC initiation under environmental and mechanical conditions directly relatable to intended use, to prevent unexpected failures for future alloys. Directions for future high-strength 7xxx series aluminum alloy development and EIC assessment to provide quantitative data relatable to service conditions and input for structural design and for service life prediction are discussed.

Grey Wolf Optimizer for enhancing Nicotiana Tabacum L. oil methyl ester and prediction model for calorific values

Modelling and enhancing the production of green diesel in biodiesel industries have been hampered by the failure of the conventional approach to pursue space with continuous convergence velocity, being entombed in local minima, and maintaining unwavering resolutions. The study presented for the first time the optimization protocol for the development of biodiesel production from tobacco seed oil (TSO) on the batch reactor aided by the unique Grey Wolf Optimizer-Response Surface Methodology-Artificial Neural Network (GWO-RSM-ANN) techniques. Lower calorific value (LCV), higher calorific value (HCV), and specific heat capacity (Cp) correlations were postulated for tobacco seed oil methyl ester (TSOME/B100/TSOB) and diesel blends. RSM, ANN, and GWO approaches were used to model TSOME's main production yield. The ASTM test methods were used to examine the significant basic properties of the fuel categories, while the LCV and HCV were detected using standard procedures. Maximum TSOME yield (90.2%) was obtained at methanol/TSO molar ratio of 5.95, KOH content of 1.15 wt. %, and methylic duration of 77.6 min. The ANN model configuration (3-15-1) that was developed showed more adaptability and nonlinearity. The estimated coefficient of determination (R 2 ) of 0.9999, mean average error (MAE) of 0.00035, and RMSE of 0.00105 for the GWO model compared to those of R 2 of 0.9825, MAE of 1.3145, and RMSE of 1.7087 for RSM model; and R 2 of 0.9976, MAE of 0.2405, and RMSE of 0.6381 for ANN model vindicate the superiority of GWO model over the RSM and ANN models. The major fuel properties agreed with the ranges of the ASTMD6751 and EN 14214 specifications. The LCV, HCV, and Cp are also correlated with the TSOME fraction through the linear equations. There were excellent correlations between the analyzed and calculated values for the LCVs and HCVs. The maximum absolute error between the measured and estimated LCV and HCV are 0.108% for 20%TSOME (20% TSOME +80% diesel fuel), and 0.17% for pure diesel, respectively. The model and correlations can offer biodiesel and automobile industries with database information.

Experimental Investigations on Static, Dynamic, and Morphological Characteristics of Bamboo Fiber-Reinforced Polyester Composites

The use of natural fiber-reinforced polymer composites has increased over a period of time, majorly due to the ecosustainability and biodegradability of the composites. Among several grades of natural fibers, bamboo fibers offer numerous environmental and cost benefits and possess excellent mechanical characteristics. The superior properties of the bamboo fibers have triggered the research interests in the domain of bamboo fiber-reinforced polymer composites. Among the polymers, polyesters are long chain molecules made up of atoms arranged in various ways with other elements to form the basic building blocks of a polymeric chain. Polyester is being increasingly employed in today’s industrial products due to its inherent advantages. As a result, based on the potential properties of bamboo fibers as reinforcing materials and polyester resin as matrix material, the biocomposites are synthesized by hand lay-up technique and the specimens cut as per the standard dimensions and subjected to mechanical investigations, vibration, and morphological characterization as per the ASTM test methods. The increase in fiber weight content has enhanced flexural, tensile, and impact characteristics and improved the damping characteristics of the composite specimens. The microstructural evaluations have revealed the uniform distribution of the bamboo fibers in the resin, and the morphological studies of the fractured specimens have revealed that the fracture is majorly due to the matrix cracks rather than the fiber debonding, which is a major attribute ascertaining the strong coherent strengthening mechanism brought about by the inclusion of bamboo fiber in the polyester resin.

Virucidal activities of novel hand hygiene and surface disinfectant formulations containing EGCG-palmitates (EC16)

BackgroundNon-toxic hand hygiene and surface disinfectant products with virucidal activity against alcohol-resistant nonenveloped norovirus are in urgent need. MethodAlcohol-based formulations were made with epigallocatechin-3-gallate-palmitate (EC16), an FDA accepted food additive. Based on in-house testing of formulations, 3 prototypes, PTV80 hand gel, PST70 surface disinfectant spray and PST70 surface disinfectant wipe, were selected from in-house tests for independent testing at GLP (good laboratory practice) laboratories according to EN 14476:2019 (hand gel), ASTM test method E1053-20 (spray), and ASTM E2362-15, E1053, and ASTM E2896-12 (wipe). ResultsThe PTV80 hand gel prototype demonstrated a >99.999% reduction of murine norovirus S99 infectivity in 60 seconds. Carrier testing of the PST70 surface spray and surface wipe demonstrated reduction of feline calicivirus infectivity by >99.99% in 60 seconds. In addition, testing with human coronavirus and human herpes simplex virus demonstrated >99.99% efficacy in 60 seconds, consistent with broad spectrum virucidal activity. ConclusionsThe novel non-toxic prototypes containing EC16 were found to be suitable for use in future hand sanitizer gel, surface disinfectant spray and wipe products against norovirus. Products based on these formulations could be used safely to help prevent and control norovirus and other emerging virus outbreaks, pending future studies.

Modeling fracture in viscoelastic materials using a modified incremental meshfree RPIM and DIC technique

In the present work, fracture mechanics of linear viscoelastic materials is investigated numerically and experimentally. Herein, an effective and accurate meshfree method is developed to analyze fracture mechanics in viscoelastic problems. To this end, an incremental approach with higher-order finite difference (FD) schemes for analysis of viscoelastic materials in the time domain, along with an improved meshfree method based on the global weak formulation, i.e. the radial point interpolation method (RPIM), is employed. An accurate and efficient integration approach with minimum computational cost, i.e. the background decomposition method (BDM), is also used to compute the domain integrals. To evaluate the accuracy and efficiency of the proposed numerical method, first, two example problems are provided and the robustness of the presented method is assessed. Then, a non-contact full-field optical method, i.e. the digital image correlation technique, is utilized to investigate the viscoelastic fields of a polymer, polymethyl-methacrylate (PMMA), during crack propagation in mode I. Also, in order to properly model the fracture behavior of this material by the meshfree RPIM, the mechanical properties of the PMMA, including the Prony viscoelastic parameters, are obtained by an ASTM test method. Moreover, the obtained results from the DIC test and also the load-displacement curve of the cracked specimen are compared with the results of the proposed meshfree RPIM and a very close agreement is observed.

Evaluation of Current ASTM Standards for ASR Prevention When Fine Lightweight Aggregates Are Used

Abstract Previous research has shown that using fine lightweight aggregate (FLWA) can be a promising strategy to mitigate alkali-silica reaction (ASR) in mortar and concrete. However, limited studies focused on assessing current ASTM standards for their applicability in evaluating the efficacy of ASR mitigation using FLWAs. In this study, three commercially used FLWAs (expanded shale, clay, and slate) were investigated in mortar and concrete mixtures with reactive aggregates of different levels of reactivity. ASTM test methods, including ASTM C289-07, Standard Test Method for Potential Alkali-Silica Reactivity of Aggregates (Chemical Method) (Withdrawn 2016); ASTM C1260-14, Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) (Superseded); and ASTM C1293-18, Standard Test Method for Determination of Length Change of Concrete due to Alkali-Silica Reaction (Superseded), were completed. Fine normal-weight aggregates were replaced by the FLWA at 25 % and 50 % by volume in the concrete mixtures, and 25 %, 50 %, and 100 % in mortar mixtures. Results showed that ASTM C1260-14 and ASTM C1293-18 can be used to evaluate the mitigation efficacy when pre-wetted FLWAs were used. The ASTM C289-07 test is not a reliable test method to study the reactivity of the FLWAs, but the results can be used to indicate the alkali-consuming ability of the FLWAs. All three FLWAs were effective in reducing ASR-induced expansion in both ASTM C1260-14 and ASTM C1293-18. The investigated FLWAs were especially effective in the concrete when moderately reactive aggregates, as classified by ASTM C1778-14, Standard Guide for Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete (Superseded), were used. For concrete with a highly reactive aggregate or very highly reactive aggregate, other mitigation strategies may need to be combined with FLWAs to effectively mitigate ASR.

Screw inserting in different phase of cement affect the pull-out strength of cement augmented screws

BackgroundFor large bone defects, after curettage of aggressive bone tumors; such as giant-cell tumors, cementation with supplement internal fixation was used to prevent subsequent collapse of the cement-bone constructs. The purpose of this study is to compare the pull-out strength of cement augmented screws between inserting screws in the working phase or hard phase of bone cement. HypothesisTiming at which completed screw insertion takes place affecting the pull-out strength of cement augmented screws. MethodsPull-out strength was compared between screws; inserted within the working phases of cement, and after the cement was hardened in high viscos cement blocks. Each group consists of 10 cortex screws, 10 cancellous screws and 10 locking screws. The pull-out strength test was followed using the instructions of ASTM F543-13e1 Standard Specification and Test Methods, for Metallic Medical Bone Screws. ResultsScrews that were inserted in the working phases of cement had significantly higher pull-out strength, than those inserted in hard cement (p=0.021). The pull-out strength was statistically significant in difference among the types of screws (p<0.001), with locking screws having the highest pull-out strength. Furthermore, the pull-out strength of locking screws revealed no significant difference when either; inserted during the working or hardened phases of bone cement. ConclusionInsertion of screws during the working periods of PMMA cement had higher pull out strength compared to the hard phase of cement. Hence, we recommend performing internal fixation before cementation after curettage of aggressive bone tumors. However, if the surgeon prefers to pack the cement first, for the benefit of avoiding residual bone defects, we suggest using a locking plate system to achieve comparable pull-out strength. Level of evidenceIn-vitro study.

Designing GFRP-Reinforced Tilt-up Wall Panels

Tilt-up construction was effectively enabled on a wide scale in 1979, when the ACI committee 551 report on Tilt-up construction was published, the Recommended Tilt-Up Wall Design, aka, the Yellow Book and the subsequent ACI-SEASC Task, aka the Green Book, and another Tilt-up design and construction manual developed by the ACI in 1988. The Tilt-up Concrete Association was created in 1986 by a group of industry professionals who had the need of an organization dedicated to the industry. ACI 551 maintains a document outlining the standard practice for contemporary Tilt-up design and construction. The ACI 551 document does not consider walls reinforced with non-ferrous reinforcement. However, recent events have made glass fiber-reinforced polymer rebar a more economical option when compared to traditional steel reinforcement. This white paper is intended to provide the unfamiliar engineer a bridge between the ACI 318, ACI 551 and ACI 440 documents to engineer a tilt-up wall including differences between GFRP reinforcement and steel reinforcement with respect to design. Steel, is an isotropic ductile metal extensively used in construction, mechanical, and electronic devices. Steel is often designed as elastic-perfectly plastic where it has an elastic modulus of 29,000ksi and yield stress of 60ksi. GFRP reinforcement is considered brittle-elastic with an elastic modulus often between 6,000ksi – 8750ksi and guaranteed ultimate tensile strength between 90-150ksi. Figure 1 presents an example of the design-assumed uniaxial stress versus strain comparing traditional steel and GFRP. While GFRP reinforcement has different physical and mechanical properties the differences and behaviors are well understood by the engineering community. There are ASTM material standards for GFRP bars, namely ASTM D7957 and a complete suite of ASTM test method by which the basic properties are verified. The following sections will illustrate the differences between steel and GFRP reinforced concrete members with a focus on slender tilt-up wall panels.

Turbidity-based measurement of bleeding in fresh cement paste as affected by cellulose nanofibres

This study examined bleeding in cement paste as affected by cellulose nanofibres prepared with varying the content of carboxyl groups that were grafted onto the fibre surface. Alongside the conventional ASTM test method, bleeding was further evaluated using a turbidity scanner. A linear correlation was obtained between the bleeding heights as found from the two techniques. The results demonstrate that adding cellulose nanofibre (CNF) significantly reduces the bleed-water volume. Besides, the layer of bleed water in mixtures containing the CNF was more turbid. Clearly, the water retention capacity of CNF hinders the cement grains from settling down and thereby the nanofibres obstruct the upward migration of free water. As well, the higher the carboxyl content, the higher the fibre dosage permissible. And, although it was independent of the amount of carboxyl groups, bleeding was progressively less with an increase in the nanofibre dosage. However, in the presence of a superplasticizer, the cellulose nanofibres were less effective in reducing the bleeding.

Effect of spent engine oil contamination on the soil properties in selected automobile mechanic villages in Enugu, Enugu State, Nigeria

AbstractThis study was carried out to determine the effect of spent engine oil on the soil properties in selected automobile mechanic villages in Enugu, Enugu State, Nigeria. Spent engine oil (SEO) was collected and characterized according to ASTM test methods. Soil samples were collected at 0–30 and 30–60 cm depths from the mechanic villages and uncontaminated agricultural farmlands 500 m away as control and properties analyzed. The extent of contamination of heavy metals in soils was assessed. The results of the SEO characterization showed the values of 2.87 wt%, 218°C, 13.18 mg/kg, 0.75 mg/kg, 4.06 mg/kg, and 0.94 mg/kg for toluene insoluble, flash point, Pb, As, Cr and Cd. The soil bulk density, pH, TOC, TOM, N, P, Cu, Cd, Pb, and Fe decreased with increasing depth while particle density, TSP, S, Cr, and As increased with increasing depth. The ANOVA results showed that a statistically significant difference existed between values of soil parameters (p &lt; 0.05), indicating that SEO has a significant effect on soil properties (α = 0.05). The study will provide useful insights for developing a precautionary strategy and inform environmental policy implementation for an effective risk management approach in the study area.