Tests Of Gravity Research Articles

Signatures of Quantum Gravity in the Gravitational Self-Interaction of Photons.

We propose relativistic tests of quantum gravity using the gravitational self-interaction of photons in a cavity. We demonstrate that this interaction results in a number of quantum gravitational signatures in the quantum state of the light that cannot be reproduced by any classical theory of gravity. We rigorously assess these effects using quantum parameter estimation theory and discuss simple measurement schemes that optimally extract their signatures. Crucially, the proposed tests are free of QED photon-photon scattering, are sensitive to the spin of the mediating gravitons, and can probe the locality of the gravitational interaction. These protocols provide a new avenue for studying the quantum nature of gravity in a relativistic setting.

Geological and geotechnical assessment of natural sands in Ilorin, Nigeria

The quality of the aggregates used inplastering mortar contributes to the properties of the mortar. This study evaluated the suitability of two grades of sand – sharp sand collected along active/old river courses and plastering sand collected from borrow pits – as plastering materials. X-ray diffraction and X-ray fluorescence analysis were used to study their mineralogy and major, minor and trace element components. Grain-size distribution analysis, natural moisture content, specific gravity, Atterberg limits, matric suction and permeability tests were also carried out on the sand samples. In both sands, the silica content was more than 80%. The plastering sand had a higher natural moisture content than the sharp sand. The fineness modulus ranged from 1.31 to 1.83 and 0.53 to 1.01, respectively, for the sharp sand and the plastering sand. The permeability coefficients and matric suction of the sharp sand were larger than those of the plastering sand. This implies that sharp sand will allow easier water passage through its pore spaces, therefore tending to exist in a dryer state than plastering sand. The tested sharp sand may be suitable for plastering because the test results were within the acceptable limits for good plastering materials according to national and international standards.

CHARACTERISTICS OF THE MIXTURE OF LATASTON (HRS-WC) WITH DOLOMITE LIMESTONE AS A FILLER IN ASPHALT MIXTURE

Indonesia is a country that has a lot of natural resources; one of the natural resources in Indonesia is lime. In Palembang, there is a large-scale dolomite lime-producing company that covers the territory of Indonesia. The content in the dolomite lime is Magnesium Oxide (MgO) ≥ 18% and Calcium Oxide (CaO) ± 30%. The purpose of this study is to utilize dolomite lime as a mixture of asphalt concrete layers and to find out changes in the characteristics of the HRS-WC mixture due to the use of dolomite lime as a filler. The experiment refers to Bina Marga 2018 revision II. The method used in this study is the experimental method, which is carried out by conducting experimental activities to obtain data. The aggregate specific gravity test obtained more than 2.5 gr/cm3 results, which qualify the 2018 Bina Marga revision II specifications. Examination of the wear of the coarse aggregate yielded results that fulfil the 2018 Bina Marga revision II specifications. The filler used in this mixture is applied on combination with a percentage of 0% rock ash and 100% dolomite lime, then 25% rock ash and 75% dolomite lime, then 50% rock ash and 50% dolomite lime, then 75% rock ash and 25% dolomite lime, and 100% rock ash and 0% dolomite lime. %. The Marshall results from the percentage of 100% rock ash filler content and the percentage of 0% OAC dolomite lime filler content of 6.5% obtaine a stability value of 914.821 Kg, a flow value of 3.45 mm, and a Marshall Quotient value of 265.286 Kg/mm. The volumetric value of the percentage of 100% rock ash filler content and the percentage of dolomite lime filler content of 0 % OAC 6.5% deliver a VIM value of 4.153%, a VMA value of 18.391%, a VFB value of 79.671%.

Effects of Partial Replacement of Cement and Lime with some Agrowaste Ashes on the Geotechnical Behaviour of Lateritic Soil

In this study, the optimum stabilizer content for a poor lateritic soil intended as subgrade material for a pavement was sought. The natural soil was first characterized and classified and the soil fall into the class of A-6 based on Nigeria General Specifications for Roads and Bridges (NGSRB) AASHTO soil class for pavement construction. The soil was stabilized at three binder points of 4%, 8% and 12% which coincided with specification limits for cement based on NGSRB with the range of 7-11% recommended for soils in the class A-6. The results from the compaction tests and unconfined compressive strength (UCS) tests show that the suitable stabilizer falls within the specified range of 7 – 11%. Binder contents/proportions of 4% RHA, 8% RHA, 8% (50R + 50O), 4% (60C/L + 40R/O), 8% (70C/L + 30R/O), 8% (0C/L + 100R/O), 8% (50C/L + 50R/O) gave the most promising results of MDUW and UCS. In other to carry out a comprehensive investigation of the properties of the soil to determine which of the promising binder contents/proportions would be most suitable as stabilizer for the soil, it was recommended that other qualifying tests of specific gravity, Atterberg limits, CBR, UCS, durability and permeability tests be carried out for these recommended binder contents/proportions.

Perturbations of Spinning Black Holes beyond General Relativity: Modified Teukolsky Equation

The detection of gravitational waves from compact binary mergers by the LIGO/Virgo collaboration has, for the first time, allowed for tests of relativistic gravity in the strong, dynamical and nonlinear regime. Outside Einstein's relativity, spinning black holes may be different from their general relativistic counterparts, and their merger may then lead to a modified ringdown. We study the latter and, for the first time, derive a modified Teukolsky equation, i.e., a set of linear, decoupled differential equations that describe dynamical perturbations of non-Kerr black holes for the radiative Newman-Penrose scalars $\Psi_0$ and $\Psi_4$. We first focus on non-Ricci-flat, Petrov type D black hole backgrounds in modified gravity, and derive the modified Teukolsky equation through direct decoupling and through a new approach, proposed by Chandrasekhar, that uses certain gauge conditions. We then extend this analysis to non-Ricci-flat, Petrov type I black hole backgrounds in modified gravity, assuming they can be treated as a linear perturbation of Petrov type D, black hole backgrounds in GR by generalizing Chandrasekhar's approach, and derive the decoupled modified Teukolsky equation. Our work lays the foundation to study the gravitational waves emitted in the ringdown phase of black hole coalescence in modified gravity for black holes of any spin. Our work can also be extended to compute gravitational waves emitted by extreme mass-ratio binary inspirals in modified gravity.

Effect of Using Moringa Leave (Moringa Oleifera L.) and Pineapple (Ananas Comosus) Leaf Lotion Gel Lotion on Skin Moisture

The compounds contained in Moringa leaves are rich in phenolic acids, flavonoids, alkaloids, tannins, glucosinolates and isothiocyanates, all of which are antioxidants. Moringa leaves contain B2 which is useful for treating and maintaining skin moisture. Pineapple fruit contains vitamin C and vitamin A, the second vitamin is known to have antioxidant activity that can stop the reaction of forming free radicals. Moringa leaves and pineapple contain antioxidant compounds which are useful as skin moisturizers which are formulated in the form of a gel lotion. This study aims to determine the effect of using moringa leaf extract gel lotion and pineapple fruit on skin moisture. This study was initiated by formulating lotion preparations with the addition of concentrations of moringa leaf extract and pineapple fruit, namely concentrations of 3% (F1) 4% (F2) 5% (F3). Lotion gel was evaluated for physical stability by testing pH, viscosity, adhesion, spreadability, irritation test, specific gravity test and skin moisture test. This study uses an experimental method. The results showed that the formula concentrations of 3%, 4% and 5% all met the requirements of the physical stability test as a skin moisturizing lotion gel preparation. The higher the concentration of the extract, the wider the spreadability and viscosity value obtained, has no effect on adhesion and pH value. Lotion preparations of moringa leaf and pineapple fruit extracts with a concentration of 5% have a high ability as skin moisturizers. The results showed that the formula concentrations of 3%, 4% and 5% all met the requirements of the physical stability test as a skin moisturizing lotion gel preparation. The higher the concentration of the extract, the wider the spreadability and viscosity value obtained, has no effect on adhesion and pH value. Lotion preparations of moringa leaf and pineapple fruit extracts with a concentration of 5% have a high ability as skin moisturizers. The results showed that the formula concentrations of 3%, 4% and 5% all met the requirements of the physical stability test as a skin moisturizing lotion gel preparation. The higher the concentration of the extract, the wider the spreadability and viscosity value obtained, has no effect on adhesion and pH value. Lotion preparations of moringa leaf and pineapple fruit extracts with a concentration of 5% have a high ability as skin moisturizers.

Formulasi Dan Uji Sifat Fisik Sediaan Sabun Wajah Cair Ekstrak Biji Alpukat (Persea americana M) Dengan Variasi Natrium Lauril Sulfat Sebagai Surfaktan

Avocado seeds have antibacterial activity. These antibacterials can be used to clean the skin. Then a formulation of a liquid facial soap was made from avocado seed extract. One of the ingredients that affect the physical properties of liquid facial soap is sodium lauryl sulfate as a surfactant. Sodium lauryl sulfate as a surfactant is known to have cleaning power and can produce a stable and qualified foam. . This study aims to determine the optimal concentration of sodium lauryl sulfate to produce a liquid facial soap that is stable and meets the requirements. This type of research is experimental. Avocado seeds are extracted by maceration method. Liquid facial soap was made into three formulas using varying concentrations of sodium lauryl sulfate FI (0.5%), FII (1.5%) and FIII (2.5%). The physical properties of liquid facial soap observed included organoleptic test, pH test, viscosity test, specific gravity test, foam height test, homogeneity test and skin irritation test in liquid facial soap. The results showed that the use of varying concentrations of sodium lauryl sulfate in FI, FII and FIII fulfilled the criteria for testing the physical properties of avocado seed extract liquid facial soap in the organoleptic test, pH test, viscosity test, specific gravity test, foam height test, homogeneity test and skin irritation test. Of all the formulas that met the criteria for sodium lauryl sulfate concentration, the most optimal formula was formula III (2.5%).

Female Reproductive Potential and 3x by 2x Breeding Approach for Hybrid Seeds Development in Sukali Ndizi Genotype (Musa genome AAB)

Sukali Ndizi is one of the most popular local desert banana cultivars in Uganda. The crop is affected by a number of diseases and pests. Genetic improvement of the crop by hybridization may be hindered by very low seed set and poor seed germination. The main characteristics for assessing the female reproductive potential (seed set, seed quality and embryo germination of hybrid seeds) and 3x by 2x breeding approach were assessed in crosses of eleven different male diploid parents either wild or improved diploids with Sukali Ndizi landrace as the female parent for a period of 5 consecutive years planted in pollination blocks at National Agricultural Research Laboratories Kawanda (NARL). The month of pollination did not show any pattern throughout the pollination period but the crosses showed considerable variability in seed set, seed quality, and seed germination for different male diploids used. The water gravity test which differentiated the extracted seeds as sunken/viable and floating/nonviable seeds showed that a substantial amount of seed was floating and the sunken externally characterized by black hard integuments was only 39% with a range = 24%–60% which contained embryos, of which 22% (range = 0–37%) germinated. The increase in non-viable seed suggested that ovule abortion in Sukali Ndizi which mainly involved embryo and endosperm abortions was the cause of limited seed germination and the paternity of the zygotes was a major factor underlying abortions. Flow cytometric analysis of nuclear DNA content was used to estimate ploidy levels of the progenies with results showing that using 3x by 2x breeding approach differing levels of ploidy were achieved [3x (288), 4x (61), 5x (14) and 2x (2)] signifying the predominance of 3x progenies and the presence of 5x and 4x conforming to the possibility of sexual polyploids. Although pollination of Sukali Ndizi can be done all around the year, the seed set both quantity and quality and germination were very poor, necessitating the development of an efficient regeneration protocol for zygotic embryos at varying maturity stages to increase the recovery of hybrids.

Analytical performance evaluation of two automated urine chemistry analysers using two levels of commercially available quality control material.

Evaluate two point-of-care urine chemistry analysers, VetScan SA and VetLab UA using assayed, bilevel (two concentrations) urine quality control material to determine if performance is acceptable for semiquantitative clinical urine chemistry analysis. Normal and abnormal urine quality control material sent to 23 veterinary practices was evaluated three times by each clinic on in-clinic automated urinalysis instruments. Accuracy, precision and clinical utility were evaluated. Normal urine quality control material: Results for blood, glucose, ketones and bilirubin were 100% accurate and precise for both analysers, and pH values were accurately acidic to neutral. However, pH from VetScan SA had clinically significant negative bias. Abnormal urine quality control material: VetScan SA: blood, microalbumin and bilirubin were 100% accurate; glucose, ketones, and protein demonstrated ≤10% inaccuracy; pH demonstrated 34% inaccuracy. VetLab UA: blood, ketones and bilirubin were 100% accurate; glucose and protein demonstrated ≤10% inaccuracy; pH was 100% accurately neutral to alkaline. VetScan SA had marked negative pH bias versus VetLab UA resulting in clinically significant, overly acidic results. Specific gravity, nitrite, and leukocyte test pads should not be used. Both instruments had excellent performance in normal quality control material. While blood, glucose, protein and bilirubin are correctly identified as present in abnormal quality control material, exact concentrations cannot be interpreted due to imprecision. Only semiquantitative results, not numerical values implying quantification, should be reported from urine test strips.

Engineering properties of different fiber-reinforced metakaolin-red mud based geopolymer mortars

In this research, fiber reinforced metakaolin-red mud based geopolymer mortar was produced by using recycled concrete aggregate and industrial waste glass powder as filler materials. Three different types of fibers were used to reinforce the geopolymer mortar, namely brass-coated steel fibers, polyamide fibers, and polyethylene fibers, with four different proportions by volume (0.25%, 0.5%, 0.75%, and 1.00%). Experiments for compressive strength, flexural strength, splitting tensile strength, flexural toughness factor, ultrasonic pulse velocity, and abrasion resistance were conducted to investigate the influence of fibers on mechanical properties. Specific gravity, porosity, and water absorption tests were conducted to examine the physical properties. Additionally, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses were performed. The results indicate that 50% replacement of recycled concrete aggregate and glass powder as filler material yielded the optimum strength properties. Moreover, addition of fibers enhanced the strength properties of the geopolymer mortar, for instance, the mixture having polyethylene fibers with a fiber volume of 0.75% improved the flexural strength up to 48.72%, and the mixture containing steel fibers with a fiber fraction of 0.25% showed the highest value of splitting tensile strength and improved up to 40% when compared to non-fibrous control mixture. Polyethylene fiber-reinforced mixture showed a notable toughening impact and showed a flexural toughness factor up to 66.29% more than the control sample. The reason of this improvement is because of the bridging effect of fibers. According to the findings, the 0.25% steel fibrous samples showed the best result in terms of minimum weight loss due to abrasion and showed 36.08% more abrasion resistance compared to non-fibrous control mixture. Moreover, increase in porosity was observed in fiber-reinforced mixtures. The lack of CaO content is found responsible for poor mechanical strength and bending performance of fibrous metakaolin-red mud based geopolymer mortars specimens.

Constraining deviations from spherical symmetry using γ -metric

The $\ensuremath{\gamma}$-spacetime metric is a static and axially symmetric vacuum solution of the Einstein equation. This spacetime represents a naked singularity and it has an extra parameter $\ensuremath{\gamma}$ which signifies deviations from spherical symmetry. In this work, we study the possibility of constraining the deformation parameter with astrophysical observations. We start with gravitational lensing in the weak- and strong-field limits and calculate the respective deflection angles to show that only strong-field lensing observations will be able to constrain $\ensuremath{\gamma}$ independently. Later we study two other classical tests of gravity: Shapiro time delay and precession of perihelion. We show that, out of these two experiments, the deformation parameter affects the observables only in perihelion shift.

On the origin of force sensitivity in tests of quantum gravity with delocalised mechanical systems

The detection of the quantum nature of gravity in the low-energy limit hinges on achieving an unprecedented degree of force sensitivity with mechanical systems. Against this background we explore the relationship between the sensitivity of mechanical systems to external forces and properties of the quantum states they are prepared in. We establish that the main determinant of the force sensitivity in pure quantum states is their spatial delocalisation and we link the force sensitivity to the rate at which two mechanical systems become entangled under a quantum force. We exemplify this at the hand of two commonly considered configurations. One that involves gravitationally interacting objects prepared in non-Gaussian states such as Schrödinger-cat states, where the generation of entanglement is typically ascribed to the accumulation of a dynamical phase between components in superposition experiencing varying gravitational potentials. The other prepares particles in Gaussian states that are strongly squeezed in momentum and delocalised in position where entanglement generation is attributed to accelerations. We offer a unified description of these two arrangements using the phase-space representation of the interacting particles, and link their entangling rate to their force sensitivity, showing that both configurations get entangled at the same rate provided that they are equally delocalised in space. Our description in phase space and the established relation between force sensitivity and entanglement sheds light on the intricacies of why the equivalence between these two configurations holds, something that is not always evident in the literature, due to the distinct physical and analytical methods employed to study each of them. Notably, our findings demonstrate that while the conventional computation of entanglement via the dynamical phase remains accurate for systems in Schrödinger-cat states, it may yield erroneous estimations for systems prepared in squeezed cat states.

Modeling and simulation of heterogeneous moisture content influence on foundation settlement in silt clay

In this paper, modeling and simulation techniques with experimental setup values were used to investigate the effects of foundation settlement on the heterogeneity of moisture content, formation characteristics, and ground water. The study was conducted at Obirikom in Rivers State's Ogba Egbema Local Government Area; the samples were subjected to the following laboratory tests: particle size analysis, Atterberg limit tests, compaction test, natural moisture content test, specific gravity, and consolidation test, which revealed that the soil was predominantly clay deposited. Modeling and simulation were used to predict how different soil conditions affected the settlement of a foundation. The study observed heterogeneous soil deposition as it reflected on soil properties, and the study on foundation settlement influence explained the heterogeneous impacts on moisture. Permeability, plastic and liquid limits, as well as other soil properties such as moisture content, water content, and dry density, was investigated. Significant parameters were observed in the study, such as dry density, which is directly proportional to plasticity as settlement increases in moisture until optimum moisture content is observed at the level where settlement decreases to a minimum. The moisture content of the settlement increased while exceeding the optimum moisture content.

Suitability of Conventional Ballast Mixed with Concrete Debris and Bottom Ash Waste

The use of waste materials as a substitute for natural aggregate has been widely tested in all areas of the construction industry. Yet, there is a lack of study on the suitability of the physical properties of waste material when used as one of the components in track ballast. This study evaluates the suitability of conventional ballast (CB) incorporated with concrete debris (CD) and bottom ash (BA) as track ballast material. To achieve the objective, sieve analysis, shape analysis, specific gravity test, water absorption test, and permeability test were carried out. Furthermore, microscopic analysis was used to validate the presence of voids. The result shows that the waste mixed ballast has a coefficient of uniformity (Cu) in the range of 1.92 to 12, a coefficient of curvature (Cc) in the range of 0.8 to 1.18, fines less than 14 mm account for 0.1 % to 28 %, and the mean size is in the range of 22.5 mm to 27.5 mm. Furthermore, the flakiness ranged from 7.56% to 22.5%, the void ratio was 0.43 to 0.55, and water absorption was 2.86% to 4%. The specific gravity was found to range from 2.30 to 2.77 when the permeability measurement was in between 30 cm/sec to 61 cm/sec. All these promising values of engineering properties exhibit the confidence of a suitable alternative to track ballast materials. Hence, CD and BA waste materials incorporated into conventional ballast have a high potential to exhibit better performance and reduce the dependency on natural aggregate.

Geological and Geotechnical Assessment of Aggregates Used in Nagar Parker District Tharparkar Sindh Pakistan

Abstract This study aims to determine the geology of granite and evaluate the engineering properties of the samples to make recommendations for the construction industry. The study area is situated in the Nagar Parker complex in Pakistan, which is located in the extreme south-east of the Thar District and the desert of the Sindh Province, near the Run of Kutch (240° 15′–35 30′ N, 70° 40′–58 07′ E), and it covers ca. 500–1,000 km2. In this region, several Quaternary deposits, subordinate and dispersed Jurassic–Tertiary sandstones and clays are overlying the Nagar Igneous Complex basement. According to international standards, there are various possible aggregate sources. However, only a few of them have been reviewed for suitability reasons. Six quarries in Nagar Parker, Pakistan, were selected for evaluation as coarse aggregate in concrete construction and civil engineering works in this research. Although the aggregates from the six quarries are specified and already widely used in the Sindh Province, there is a lack of studies on their geological properties. The results of the presented research revealed that samples from Dhedvero, Karai, Nagarparkar, Mokrio, Dinsi and Wadlai meet all of the international standard requirements for aggregates. Geotechnical, petrographic and geochemistry laboratory tests were conducted in this research and included bulk density, water absorption, specific gravity test, index of flakiness and elongation, soundness aggregate test, crushing value aggregate, impact value aggregate and abrasion value of Los Angeles. Furthermore, chemical alkali-silica reaction potential test and petrographic examination were tested. As a result, we evaluated the properties of granite, which is a crystalline igneous rock with a visibly crystalline structure and texture, made up of feldspar, i.e., potash feldspar and oligoclase. The evaluated minerals are compatible with the standards of civil engineering works and can be used as a concrete aggregate. The evaluated three types of minerals included Dhedvero simple intrusion, Nagar pink granite and grey granite.

Galaxy three-point correlation function in modified gravity

The next generation of galaxy surveys will provide highly accurate measurements of the large-scale structure of the Universe, allowing for more stringent tests of gravity on cosmological scales. Higher-order statistics are a valuable tool to study the non-Gaussianities in the matter field and to break degeneracies between modified gravity and other physical or nuisance parameters. However, understanding from first principles the behavior of these correlations is essential to characterize deviations from General Relativity (GR), and the purpose of this work. This work uses contemporary ideas of standard perturbation theory on biased tracers to characterize the three-point correlation function at tree level for modified gravity models with a scale-dependent gravitational strength, and applies the theory to two specific models [$f(R)$ and DGP] that are representative for Chameleon and Vainshtein screening mechanisms. Additionally, we use a multipole decomposition, which apart from speeding up the algorithm to extract the signal from data, also helps to visualize and characterize GR deviations.

Quantum Uncertainty Limit for Stern-Gerlach Interferometry with Massive Objects.

We analyze the fundamental coherence limit of a nano-object with an embedded spin in a Stern-Gerlach interferometer. This limit stems from the which-path information provided by the object's rotational degrees of freedom due to the evolution of their quantum uncertainty. We show that such interferometry is straightforward in a weak magnetic field and short duration. Large wave packet separation is made possible with proper fine-tuning over long durations. This opens the door to fundamental tests of quantum theory and quantum gravity. The results and conclusions are extendable to any type of interferometry with complex objects.

Strength and Workability of Concrete with Inclusion of Fly Ash, Quarry Dust and a Generic Naphthalene-based Super Plasticizer

Poor strength and workability often result in low quality concrete that can cause structural failures. This research work was conducted to improve the strength and workability of concrete at reduced amount of water due to the addition of super plasticizer by replacing partially the concrete materials: cement, with fly ash at 0%, 5%, 10% and 15%; fine aggregate, with quarry dust at 0% and 15%; and the addition of sulphonated Naphthalene Formaldehyde Condensate (SNFC) super plasticizer at 0% and 0.6% by weight of cement content reducing the amount of water to 0.45 w/c from the conventional 0.6 and 0.55 w/c ratio. Concrete cube specimens were prepared with these inclusions using grade M20 concrete and nominal mix proportion of 1:2:4. Sieve analysis test, specific gravity test, fineness test were carried out on the concrete materials, workability test was carried out on each concrete specimen, a compressive strength test and weight density test was done at 7days and 28days curing. The compressive strength of concrete made with fly ash, quarry dust and SNFC at 28days ranges from 19.58N/mm2 to 30.23N/mm2. These results were higher compared to those of conventional concrete. A combination of fly ash, quarry dust and SNFC was then recommended for solving problems of low-strength concrete.

Comparison of the Strength of Blocks Made from Sharp Sand Cement, Laterite Cement and Red Earth Cement

One of the man-made building materials used for a variety of construction projects is known as blocks. As long as the blocks can sustain the loads applied to them, they can be made from a variety of materials. The sand crete block, which is made from cement, sharp sand, and water, is a prominent type of block used for the construction of walls in many projects. This study is focused on the use of other naturally occurring building materials to replace the conventional ones in making of masonry blocks that could most likely guide in decreasing the cost of creation of blocks to be utilized for construction because of the significant expense of construction materials, such as cement and sharp sand. This study was focused to research the utilization of other construction materials (laterite and red earth). The materials used to make the blocks were subjected to a variety of tests, such as sieve analysis and specific gravity testing. Six (6) block samples were made for each of the three (3) types of blocks, totaling twenty-four (24) blocks. All of the blocks were cured using the open-air curing method, and the compressive strength test was performed on the 7, 14, 21, and 28 curing days of two (2) different blocks from each of the three (3) block types made. Every block was 5 inches in length. The results of the experiment (test) indicated that the materials were suitable for constructing blocks. After the blocks were crushed, it was discovered that none of them met the Nigerian Industrial Standard's minimum recommended standard of 3.45 N/mm2 for individual blocks (NIS 87: 2000). The compressive strength of blocks built with red earth ranged from 2.02 N/mm2 to 3.16 N/mm2, those made with laterite from 3.27 N/mm2 to 5.16 N/mm2, and those made with cement and sharp sand (sand crete) from 4.83 N/mm2 to 9.97 N/mm2.

Estimation of soil porosity in mine tailing using parameters from instrumented oedometer test

In the geological field, unexpected tailing failures have recently occurred and caused critical damage. The objective of this study was to evaluate the porosity of mine tailing using compressibility and elastic wave velocities from an instrumented oedometer test. Three samples (MS1, MS2, MS3) were obtained from the mine tailing at different depths, and their properties were assessed. The oedometer test was conducted from 0 to 1280 kPa for MS1, MS2 (with various initial stresses), and MS3, and the elastic wave velocities were measured during each loading and unloading step. The specific gravity, X-ray fluorescence, and X-ray diffraction test results revealed a portion of hematite (Fe2O3) in all the samples. According to the instrumented oedometer test, the compressibility and elastic wave velocities of the samples varied with respect to the sampling depth and stress conditions. In particular, the α factor and β exponent from the shear wave velocity followed the empirical relationship of general soil types. Empirical porosity evaluation methods reliably estimated the sample porosity at shallow depths by using the parameters from the instrumented oedometer tests. Thus, the in situ porosity at a mine tailing can be effectively evaluated if the profiling of elastic velocities in the field is available.