Cube Samples Research Articles

A probabilistic approach to determine design loads for collision between an offshore supply vessel and offshore installations

Offshore supply vessel (OSV) collisions have been identified as the most frequent type of collision accidents in the offshore oil/gas or wind turbine industries. Quantitative risk assessment (QRA) is an efficient method for evaluating the collision risk to an offshore installation. In-depth information on collision load parameters, such as incoming ship velocity and impact location, is considered prerequisite for determining the consequences of collisions with accuracy. Thus, the aim of this study is to provide a new probabilistic method for determining collision design loads. Each input parameter is treated by a probability density function, and a set of 50 prospective collision scenarios is generated using Latin hyper cube sampling (LHS) technique. Numerical computations of ship motions are performed to obtain collision load parameters. The probabilistic characteristics of the parameters using a goodness of fit test and an interval study are carried out, and best-fit probability density functions and the exceedance curves are established. A case study of the proposed method is demonstrated using a hypothetical OSV and an offshore jacket structure located in a hypothetical oceanic region. The details of the computations are documented, and the findings of the study are discussed.

Grain size distribution of aggregates of crushed concrete

The results of studies of recycling aggregates obtained by crushing concrete scrap are presented. The heterogeneity of the material received as a result of crushing concrete scrap, complicates the task of selecting the fractional composition of aggregates. The presence of the mortar component in recycled aggregates significantly increases their water demand. This indicates the expediency of their use in a mixture with natural ones. This work aimed at optimizing the granulometry of recycling rubble and sand. Concrete scrap was used for the research. It was represented by destroyed samples of heavy concrete cubes. Standard methods for determining the grain composition and properties of aggregates of concrete, manufacturing and testing mortar mixes were used. It has been shown that recycling rubble of the 5-20 mm fraction has a minimum voidness when it contains 35% of the 5-10 mm grains and 65% of the 10-20 mm grains, which is close to the ratio of these fractions in the initial crushing product. Therefore, it is advisable to use recycling rubble fractions of 5-20 mm without separation into fractions. The rather high content in the recycling sand of grains with a particle size of more than 0.63 mm indicates the feasibility of using it in a mixture with natural fine and very fine sand. A grain-optimized mixture of natural very fine sand (46% of the total mass of mixed sand) and coarse fractions (0.63–5 mm) of recycled sand (54%) is proposed. Should be considered that recycled sand has increased water demand.

The influence of the usage of Idpe plastic waste as fine aggregate in light concrete bricks

It has been a long time that red bricks become the raw material for wall compilers. As the era develops, the bricks that are light, easy to compile and not time-consuming in manufacturing are invented. The composition materials for the building blocks are cement, sand and water. In this study, the use of sand in the bricks is reduced with LDPE plastic pellets. The reason for the use of LDPE plastic pellets as substitution of plastic materials is that LDPE plastic pellets have smaller density than sand does, so that it is expected that the brick becomes lighter although consists of the same composition and it can also reduce environmental problems as LDPE plastic waste is difficult to be decomposed by nature but gradually produced by humans that results in excessive waste The LDPE plastic pellets utilized are used LDPE plastics that are recycled into plastic pellets. The sample in this study consists of cylinder with diameter of 15 cm and height of 30 cm as sample of trial mixes test, concrete bricks with size of 40 cm x 20 cm x 10 cm, cube with size of 5 cm x 5 cm x 5 cm and briquette. The trial mixes samples will be treated for 7 days and the brick, cube and briquette samples will be treated for 28 days prior to testing. Furthermore, the sample will be tested with visual, content weight, absorption, compressive strength and drag strength tests. The data analysis uses SNI 03-0349-1989 reference on Concrete Bricks as The Matching Composition for Walls. This study used a mixture of cement, sand and water with ratio of 1: 6: 0.24, this composition was obtained from experiments on several specified compositions. The composition of substitute of plastic pellets used is 20% to the sand, the composition of this substitution is obtained from the experiments on several specified compositions. From the visual appearance, the content weight and absorption, both of normal brick and 20% LDPE pellets are included in the quality I, while the compressive strength test against the sample of normal brick results in quality I and 20% LDPE pellets brick results in quality III.

Statistička analiza rezultata ispitivanja fizičko-mehaničkih svojstava kontrolnih betonskih kocki

The aim of this paper is the collection, processing and statistical analysis of data from the results of testing concrete cube samples which are tested in the Laboratory for materials of the Faculty of Civil Engineering, University of Belgrade, in the period from 2012. to 2017. year. For the needs of the analysis, the data from the Report on testing of control concrete cubes were taken, the basic characteristics of hardened concrete are also classified. Statistical analysis of the date of concreting, age of samples, composition of concrete, volume mass, pressure strength, required concrete marks etc have been carried out. The statistics showed that the most commonly used cements were the following markings: CEM II A-M (V-L), CEM II A-M (S-L), CEM II A-S, with the highest share of concrete mark MB 30 with 66,8% and MB 40 with 14,3 % stake.

Fresh and hardened properties of concrete containing effective microorganisms

Nowadays, concrete is popularly used in many areas and applications in construction industry. If designed and manufactured properly it can be one of the most durable construction materials. However, during the life span of the structure the surrounding environment where the structure is built may pose long-term durability problem to concrete such as cracks and corrosion of steel reinforcement. Thus, researchers around the world continue searching for any possible means to improve concrete qualities. This paper presents study on the effects of Effective Microorganism on fresh and hardened properties of concrete. The percentage of Effective Microorganisms (EM) used in this study was 10% and incorporated in the concrete mix by replacing the water content. In this research work, a number of control and EM concrete cube samples were cast, cured in water and tested at the ages of 3, 7 and 28 days. The workability of fresh concrete was measured through the slump test. The effect of EM on hardened concrete was assessed through compression test and ultrasonic pulse velocity (UPV) test. The experimental result shows that the workability of concrete with EM was 67% higher than the control concrete. This may indicate that the EM has the potential to be used as workability enhancer. In terms of compressive strength, the EM concrete recorded 8% higher strength at 28 days compared to concrete without EM. In addition, the early strength of EM concrete was found to be higher by 41% and 27% at 3 and 7 days compared to control, respectively. The UPV result for EM concrete also shows higher value than control concrete indicating denser concrete. All experimental results indicated that the use of EM has positive effects on concrete properties.

Estimation of In-situ concrete strength using drilling resistance

Rapid and reliable condition assessment of reinforced concrete structures in high seismicity regions is a priority task in estimating their seismic safety. Non-destructive testing (NDT) methods may contribute to the condition assessment practice by providing fast and reliable strength estimation while causing minimal or no damage to the structure. Drilling resistance is an NDT method that has been used for mechanical characterization of natural stone and wood by measuring the force response for constant penetration rate and rotational speed. This paper focuses on the relationship between drilling resistance and compressive strength of concrete, including when it is combined with other NDT methods. Concrete cube samples produced using 6 different concrete mixtures were tested. Correlation equations were then obtained using statistical analysis. The results reveal that it may be possible to reliably estimate the compressive strength of concrete using drilling resistance method.

Contamination of Escherichia coli in Orange Juice in Angkringan Tourism Area, Malioboro Area, Yogyakarta

Background: Orange juice is a popular drink in terms of taste, aroma, and price. However, if the behavior of the drink handler and environmental hygiene sanitation does not meet the requirements, it will allow the beverage to be contaminated with E. coli bacteria which can cause health problems. This study aimed to examine the relationship between behavior and angkringan sanitation with the existence of E. coli bacteria on orange juice in angkringan around Malioboro area of Yogyakarta City. Methods: This was observational analytic study with cross sectional time frame. The research samples were the angkringan reseller in Malioboro Region, amounting to 40 samples, 40 samples of orange juice and 40 samples of ice cubes. Data analysis used univariate analysis and bivariate analysis with Fisher statistical test. Results: The results of univariate analysis showed the good behavior of drink handler by 60%, good sanitation angkringan as much as 52.5%, 75% of ice cubes and 80% of the qualified or was found negative based on laboratory test in orange juice. The result of bivariate analysis, there was a relationship between the behavior of the drink handler with the presence of E. coli p = 0.042. There was no relationship between sanitation angkringan with the presence of E. coli p = 0.442. There was no relationship between the presence of E. coli on ice cubes and E. coli in orange ice p-value = 0.089. Conclusion: There was no correlation between sanitation of angkringan and the presence of E. coli on ice cubes and E. coli on orange juice. There was a relationship between the behavior of the beverage processor and the presence of E. coli on orange juice. Keywords: E. coli, Behavior, Sanitation of angkringan

Composition and properties of Kazakhstani diatomaceous minerals and synthesis on their base calcium silicates for building production

The review covers existing modern technologies and researches on applying diatomaceous minerals as silicate additives to building materials. Specialists of industrially developed countries actively work in this direction and there are some of the works on the stage of implementation now. The article also describes researches of the authors on synthesis of calcium silicate and hydrated forms of ferro-calcium silicates using different kinds of Kazakhstani diatomaceous minerals from Zhalpak deposit (Aktobe region) as main siliceous component. Main topological and physical-and-mechanical characteristics of natural diatomaceous minerals were studied. It was found out that using thermally activated diatomite mixed with a plasticizing agent enlarges strength under compression and raises the brand of building materials while lowering water absorption and specific weight. It was observed that use of thermally activated highly ferriferous diatomite (20-30 % of Fe2O3) increases the strength of building materials dramatically. X-ray phase analysis of the samples of cubes from obtained composites exposed to semi-dry pressing with thermally activated ferrous diatomite followed by steam tempering showed that there were Ca(Fe, Mg)Si2 and FeAl2SiO5(OH)2 in their composition in the amount up to 1 mas. %.The technical characteristics of cubes of composition obtained with the use of thermally activated diatomite, in particular its highly ferriferrous forms, are completely meet requirements of inter-state standards GOST 379–95 to siliceous stones and bricks and sometimes overcome this norms. In future, the technology for obtaining the synthesized materials can become a base to organize new and to improve the existing industries producing dry building mixtures and strong silicate bricks in Kazakhstan.

Study of the Mechanical Properties of Jute Fiber Reinforced Cement Composites

The study results show the use of jute fibers to develop a low cost material for wall panels, roofs and other construction board. The study has been investigates the cement mechanical characteristics jute fibers reinforced concrete. Different lengths of fibers (2cm) and (4cm) were mixed to act as reinforcement for the concrete samples. The samples with different fiber percentages (0.5%, 1% and 1.5% by weight of cement) were tested in axial compression and splitting tensile strength. A total of (42) concrete cube samples (100mm*100mm*100mm) and (42) cylindrical samples (100mm*200mm) were used in the tests, these include compressive and splitting tensile strength and were conducted at (7) and (28) days of concrete age. The results showed that increasing the fiber content and length leads to a slight decrease (4.3% - 12.3%) in the compressive strength but it improves the splitting tensile strength which reached best value at the (1% by weight of cement) fiber content and (5cm) length. The increasing of splitting tensile strength was up to (19.4%) from the reference concrete strength.

Regression modeling of the strength properties of concrete reinforced with polypropylene fiber and alkali resistant glass fibre

This paper presents the result of the regression modeling of the strength properties of hybrid fiber reinforced concrete made with polypropylene fiber (PPF) and alkali resistant glass fibre (ARGF). The fibres were added to grade 25 concrete at different proportion of 0.5%, 1.0%, 1.5% and 2.0% of volume of concrete. A total of sixty three cubes samples were tested for compressive strength, twenty four cylindrical samples for split tensile strength and twenty four beam samples for flexural strength. Maximum compressive strength was attained at 1.5% fibre volume with hybrid fibre ratio of 80% ARGF and 20% PPF, maximum split tensile strength was attained at 1.0% fibre volume with hybrid fibre ratio of 80% ARGF and 20% PPF. The beam samples attained its maximum flexural strength at 1.0% fibre volume with hybrid fibre ratio of 60% ARGF and 40% PPF. Empirical expressions were established by using multiple regression analysis to predict the compressive, split tensile and flexural strengths of the hybrid fibre reinforced concrete made with PPF and ARGF. The predicted values compared favourably with the experimental results from all specimens. Keywords: alkali resistant glass fibre, compressive strength, flexural strength, hybrid fibre concrete, polypropylene fibre, regression modeling. reinforced concrete, split tensile strength

On The Relation Between Cooling Rate and Parts Geometry in Powder Bed Fusion Additive Manufacturing

Direct metal laser sintering (DMLS), one of the laser powder bed additive manufacturing technologies produces solid metal parts from 3-D CAD data, layer by layer, by melting/sintering and bonding metal powders with a focused laser beam. In this processes isn't complete melting of powder particles in micro melt pools as well as selective laser melting (SLM) and electron beam melting (EBM). Thus some different stress conditions and defects occur depending on the temperature changes during manufacturing. In this study, this problems is investigated aspect cooling rate. Cooling rate affects the solidification process in the melting (sintering) process such as casting, welding, laser assisted processes. Therefore, it also affect part quality and properties. In the scope of study, it is tried to explain how occurring the internal stresses and distortions differ depending on the cooling rates of geometrically different parts in additive manufacturing. The residual stresses and deformations are analyzed by FEA to see relation with geometry (volume, area) to cooling rate for Ti6Al4V materials. Cube shaped samples at 20, 40, 60, 80 and 100 mm edge dimensions have analysed by using FEA. Besides 10mm cube sample is manufactured as solid and verified both as experimental and numerical. Based on the FEA results, cooling rate values are changed from 1.67 to 16.67. In conclusion, the reasons of the problems occurring during laser powder bed fusion are investigated in terms of the cooling rate in relation with the samples geometry.

Steel Fibre Performance in Concrete with Expansive Additives under Restrained Hardening Conditions

Steel moulds in the form of a rigid cubical shell were developed in order to investigate single steel fibre pull-out resistance in concrete with expansive additive under restrained hardening conditions. The cubical shell (100 x 100 x 100 mm) with wall thickness of 5 mm was designed with two openings – a small 4 mm hole for fibre embedment in concrete and a larger opening for filling the concrete. Standard beam (100 x 100 x 400 mm) and cube (150 x 150 x 150 mm) samples were also manufactured and hardened under and without restrained conditions, where the restraint was realised by rigid standard steel moulds. All the restrained conditions realized by either the developed cubical steel shell (for single fibre pull-out) or existing beam and cube moulds simulate internal (from steel fibres in concrete) and external (from friction against sub-base) restraints that hinder expansion of the concrete due to the use of special expansive additives in a flooring slab structure installed on ground. Samples with a single hooked-end steel fibre (50 mm long and 0.75 mm in diameter), with and without expansive additive were manufactured and tested in the developed mould geometry. The results show that restrained expansion in concrete with expansive additives positively affects concrete compressive strength, single fibre pull-out and flexural behaviour. Concrete compressive strength increases by 7.5 %, single fibre delamination resistance increases by 24 %, the peak pull-out load by 10.8 % while the flexural strength increases by 3.1 %.

Effect of microwave power and blanching time in relation to different geometric shapes of vegetables

Microwave (MW) blanching (MWB) of vegetables has been applied in food industry as alternative to conventional treatment. Therefore, this study was aimed to evaluate the efficacy of MWB in terms of peroxidase (POD) inactivation, by applying various process conditions (MW power and process time) to different vegetables (potatoes, savoy and white cabbage), mimicking the most common geometric shapes (cylindrical, cubed, parallelepiped and slabbed). In all 3-D shapes, POD inactivation was initially achieved at the core of sample and gradually extended toward the periphery with the increase of process intensity. However, MWB appeared to be not suitable for reaching the temperature level required for the POD irreversible inactivation on the surface of vegetables, neither in 3-D nor in slabbed shape.The optimal blanching conditions (POD residual activity < 10%), determined by response surface methodology analysis were: 160 W for 120 s for cylinder and large parallelepiped samples; 160 W for 75 s for cube sample; 350 W for 45 s for small parallelepiped sample. Contrariwise, in vegetables mimicking slab geometric shape the POD inactivation did not reach the optimal endpoint of blanching treatment, neither by increasing the MW power nor extending the process time.

Characteristics of Steel Fiber Reinforced Concrete With Recycled Coarse Aggregate

Steel is one of the fibers used in fiber reinforced concrete technology. Steel fibers in concrete help to improve flexural strength and crack resistance. Today, there are critical shortages of natural resources. In this research, waste concrete is being used to produce recycled aggregate. The Recycled Coarse Aggregate (RCA) is partially replaced with the natural coarse aggregate (NCA) in concrete to analyze the mechanical properties of steel fiber reinforced concrete (SFRC). Several tests were conducted, such as compression and flexural tests. Five batches (A, B, C, D and E) of concrete cube and prism samples with different proportions of RCA (0%, 25%, 50%, 75% &amp; 100%) and 1.5% volume fraction of steel fiber were tested, together with one control sample which used 100% NCA and 0% volume fraction of steel fiber. As a result, the control sample achieved 27.32 MPa in compression strength and 0.90 MPa for flexural strength while batch A managed to achieve 48.60 MPa and 1.10 MPa respectively. The cube and prism samples of all batches (A, B, C, D, E) showed decreasing compressive and flexural strength with increasing proportion of RCA in the concrete. Four samples fully achieved more than 20 MPa of compression strength and optimum flexural strength.

A Review Paper on Specimens Size and Shape Effects on the Concrete Properties

Concrete properties are the most essential and critical physical material property when reinforced concrete structures are planned. Because of the development and in types and nature of material used to enhance the concrete innovation, materials and mix proportions, test measure, mixing strategy, and testing condition have noteworthy impacts on highlights of concrete strength, in light of the fact that the control specimen sizes and shapes might be unique in relation from State to State. Testing of mechanical properties (especially compressive strength and tensile strength) of concrete is one of the most urgent stages of development. To control the nature of the concrete, there are different molds used for pouring concrete samples according to different directions in different countries. Many researchers have realized that the specific shapes and sizes of concrete samples can cause different types in the consequences of compressive strength or tensile strength. The relationship between the compressive strength of the concrete cube and the cylinder is complex. The cylinder and concrete cube samples were compared in the pressure test by studying previous research, including the test methodology, factors affecting the cylinder / cube strength ratio, and the coefficients, equations and components of the conversion factors. Previous attempts to determine experimental transformational relationships and conversion factors have proved that it is disturbing (if not impossible) to predict the relationships between the forces of the cylinder and the cube. Previous research has shown that the ratio of the strength of the cylinder / cube is between 0.65 and 0.90, despite the fact that the ratios outside this range have been found similarly. In light of this review of previous research, the test of the cylinder is not initiated by testing the cube. This study is a review of the sample size and shape effect on concrete properties.

The Investigation into the Effect of Hydrostatic Pressure on the Engineering Properties of Hardened Concrete

The aim of this study is to investigate the effect of hydrostatic pressure on the engineering properties of hardened concrete. To this end, a concrete column with dimensions of 100 cm width, 25 cm depth and 250 cm height was produced using C20 class concrete. While pouring the concrete, 15 cm reference cube samples were taken from the fresh concrete. After 28 days, 8 from the cube samples and 128 from different hydrostatic heights, in total 136 pieces of core samples with Ø100 mm diameter were taken and their compressive strength was determined. The average compressive strength of the reference core samples was 36.95 N/mm2 and the compressive strength of other samples changed between 37.3 N/mm2 and 43.0 N/mm2 according to the hydrostatic pressure. It was concluded that compressive strength changed between 0.95% and 16.37% according to the reference sample. Statistical analysis was conducted based on the experimental results. The compressive strength of the core samples related to its hydrostatic height and physical properties were predicted with a high reliability. A model equation was formed to convert the compressive strength of the core samples into reference compressive strength according to hydrostatic height and the convertibility coefficients were ascertained.

Evaluation of wave velocity in bovine meniscus by laser ultrasound technique

Laser ultrasound technique is suitable to measure the ultrasound velocity of small samples such as meniscus. In this study, longitudinal wave velocities in bovine meniscus samples were measured using a short pulsed laser. The samples were obtained from the knee joint of bovine femurs and five cubes (3×3×3 mm3) were manually manufactured. The ultrasonic wave generated by the laser was propagated through the samples and the corresponding velocities in the axial, radial, and tangential directions were measured. The obtained velocity range was 2820–3560 m/s. The highest velocities were found in the tangential direction, followed by the velocities in the radial and axial directions, except for the samples extracted from the most posterior part of the meniscus, where the velocities were highest in the radial direction. In order to investigate the anisotropy of the meniscus, the cube samples were processed into octagonal prisms, and the velocities in the directions between tangential and axial directions were measured. The velocities observed in these directions were between the values of the ones in the tangential and the axial directions, showing the uniaxial anisotropy.

Dielectric Response of Ice Ih: Signals Perpendicular to an Electric Field of 1 Hz to 1 MHz Applied to a Cube Sample

Dielectric response signals of materials are generally detected parallel to the applied electric field. Here, we report response signals detected perpendicular to the applied field for ice Ih sampl...

Effect Of Windscreen Glass Waste Powder (WGWP) Mortar On Water Absorption

Diverting waste material from landfill sites has a big implication for the creation of new markets and has environmental benefits through offsetting the need for the extraction of raw materials. Besides, the major attention especially in construction industry is the problem to make natural resources sustainable for three to four decades in future. However, in this study finely glass powder with pozzolanic properties is found to be a partial replacement for cement and can acts as filler in the microstructure of a mortar block. Thus, a study was conducted to see the effects of various proportions of windscreen glass waste powder (WGWP) in determining the degree of water absorption on mortar incorporated with WGWP and to determine the optimum replacement to the ordinary Portland cement (OPC) with WGWP. Several compositions of WGWP (0%, 5%, 10%, 15% and 20% by cement weight) of mortar cube sample were prepared and cured at 7, 28 and 60 days to undergo a water absorption test. From this research, it shows that the use of WGWP was found to be the best features pozzolanic enough to use as a partial replacement for cement and it can reduced the pores of mortar by blocking the large voids in the hydrated cement paste through pozzolanic reaction. In the term of water absorption, the lowest reading was achieved in 15% and it can be said that 15% replacement is the optimum replacement of OPC.

The effect of stylolites on the deterioration of limestone: possible mechanisms of damage evolution

This study presents five different lithotypes of limestone containing stylolites and commonly used as dimension stones in Egypt, Hungary and Israel. All the studied limestones are generally hard, dense, with high degree of cementation and have high strength and low porosity. Stylolites are small tooth-like irregular surfaces most often developed on the carbonate-rich stones. Insoluble particles, i.e., organic matter, oxides and clays are usually incorporated within the stylolitic planes. The presence of stylolites and their filling materials generally has a large effect on the physical and mechanical properties of the host stones. The main aim of this study is to evaluate the damage mechanism of different stylolitic limestones and to understand the role of the clay in the deterioration of these stones. Hundred cube samples (2 cm) of all the studied limestones were subjected to 500 thermal cycles (10–70 °C) and 20 cube samples (3 cm) of a grey Israeli limestone with high open porosity were subjected to multiple wet/dry cycles. The changes in mass, strength, and ultrasound Vp velocity, were measured to follow any damage that happened due to cycling. The thermal cycling was proved to be an effective deterioration mechanism of both Egyptian and Hungarian lithotypes. The response of Israel grey lithotype to the wet/dry cycling was clearly shown by the splitting of the tested samples through the stylolite planes and the sharp decrease of their strength.