Minimum Strength Research Articles

Effect of sintering condition and low-temperature degradation on the flexural strength and phase transformation of zirconia

Statement of problemThe traditional sintering of zirconia takes an extended time, and accelerated treatments have been developed to reduce treatment time and manufacturing costs. Studies evaluating the effect of sintering time on the mechanical properties of zirconia are lacking. PurposeThe purpose of this in vitro study was to evaluate the effect of the sintering condition and the low-temperature degradation (LTD) of zirconia on the flexural strength of monolithic zirconia. Material and methodsZirconia specimens (LUXEN Enamel) were sintered at 1500 °C, 1530 °C, and 1560 °C for 4, 5, 6, 7, and 12 hours and subjected to LTD (n=10). Control specimens were assessed in the nontreated condition. The 3-point flexural strength was measured by using a universal testing machine. The crystal phases of the specimens were compared and quantitatively analyzed through X-ray diffraction (XRD) analysis, and the crystal grain size was measured by using a field emission scanning electron microscope (FE-SEM). Two-way ANOVA and the independent sample t test were used to analyze the experimental results (α=.05). ResultsIn the group not subjected to LTD, there was no difference in flexural strength according to the change in sintering temperature and sintering time (P>.05). The group subjected to LTD showed a difference in flexural strength according to sintering time difference (P<.001). The flexural strength of the zirconia with LTD exposure increased compared with that of the zirconia specimen not subjected to LTD (P<.001). With LTD exposure, cubic and monoclinic crystals increased, tetragonal crystals decreased, and the particle size increased. As the sintering temperature increased, the particle size increased, but not according to the sintering time. ConclusionsAt all sintering times, the flexural strength of zirconia was over 800 MPa, which is the minimum flexural strength of a 4-unit or longer prosthesis as specified in the International Organization for Standardization (ISO) 6872. With LTD exposure, the increase in the flexural strength of zirconia was associated with the phase change from tetragonal to monoclinic.

High-Sustained Concentrations of Organisms at Very low Oxygen Concentration Indicated by Acoustic Profiles in the Oxygen Deficit Region Off Peru

The oxygen deficient mesopelagic layer (ODL) off Peru has concentrations below 5 μmol O2 kg–1 and is delimited by a shallow upper oxycline with strong vertical gradient and a more gradual lower oxycline (lOx). Some regions show a narrow band of slightly increased oxygen concentrations within the ODL, an intermediate oxygen layer (iO2). CTD, oxygen and lowered Acoustic Doppler Current Profiler (LADCP, 300 kHz) profiles were taken on the shelf edge and outside down to mostly 2000 m. We evaluate here the acoustic volume backscatter strength of the LADCP signal representing organisms of about 5 mm size. Dominant features of the backscatter profiles were a minimum backscatter strength within the ODL, and just below the lOx a marked backscatter increase reaching a maximum at less than 3.0 μmol O2 kg–1. Below this maximum, the acoustic backscatter strength gradually decreased down to 1000 m below the lOx. The backscatter strength also increased at the iO2 in parallel to the oxygen concentration perturbations marking the iO2. These stable backscatter features were independent of the time of day and the organisms represented by the backscatter had to be adapted to live in this microaerobic environment. During daylight, these stable structures were overlapped by migrating backscatter peaks. Outstanding features of the stable backscatter were that at very low oxygen concentrations, the volume backscatter was linearly related to the oxygen concentration, reaching half peak maximum at less than 2.0 μmol O2 kg–1 below the lOx, and the depth-integrated backscatter of the peak below the lOx was higher than the integral above the Ox. Both features suggest that sufficient organic material produced at the surface reaches to below the ODL to sustain the major fraction of the volume backscatter-producing organisms in the water column. These organisms are adapted to the microaerobic environment so they can position themselves close to the lower oxycline to take advantage of the organic particles sinking out of the ODL.

Preparation and performance of the ultra-high performance mortar based on simplex-centroid design method

The mix proportion, phase diagram components and mechanical properties of ultra-high performance mortar (UHPM) based on simplex-centroid design method were investigated. The effects of material components, sand/binder ratio (S/B) and water/binder ratio (W/B) on the strength and fluidity of UHPM were studied. Simultaneously, the relationship between water reducer dosage and slump flow of UHPM was investigated as well as the mix proportion design and performance prediction. The results showed that the simplex-centroid design method can be used to determine the relationship between influence factors and performance of UHPM. The differences of strength phase diagram for different mix proportion of UHPM were manifested in central position of minimum strength, strength contours and gradient, and position of maximum strength. There has a quadratic function relationship between water reducer dosage, slump flow and W/B. The slump flow of UHPM increases with the increase of water reducer dosage. The UHPM can be prepared based on simplex-centroid experimental design method.

Evaluación de concreto elaborado con agregados de canteras de río y de cerro de los Andes del norte de Perú

Concrete is a versatile material, and because it is found in all types of construction, its demand has increased, thus generating an increase in the extraction of aggregates, which many times do not meet technical specifications. The aim was to comparatively evaluate concretes made with hill and river quarries, for designs with compressive strength (f'c) = 175 kg/cm2 and f'c = 210 kg/cm2. The properties of both hill and river aggregates were analyzed to calculate the dosage of the components, using the methodology of committee 211 of the American Concrete Institute (ACI); after the preparation of the specimens, the curing was carried out and later the compressive strength tests were carried out at 7, 14 and 28 days. It was determined that the concrete made with river aggregates meets the minimum compressive strength parameters; However, most of the aggregates do not comply with the Peruvian Technical Standard (NTP) 400.037 and this has a negative effect on the strength of the concrete. Therefore, the use of hill aggregates is recommended, taking into account the respective corrections in the mix design to obtain concretes with the required strengths.

The Device Using a Polydimethylsiloxane Membrane and the Phase Transition of Water

The accumulation of ice on surfaces can cause harm in many industries. Our work describes an experiment and a simulation of the deicing effect based on a simple device combining a polydimethylsiloxane (PDMS) membrane and water phase transition. The device resulted in a minimum ice adhesion strength of 0.327 kPa, and the ice adhesion strength was still less than 5 kPa after 15 cycles, which meets the requirements of automatic deicing. It also held up after flushing with water and sand currents. In addition, our finite element simulation illustrates that the ice adhesion strength decreases greatly due to the change in initial stress distribution and the separation mode of ice. The fracture between the ice and membrane initiates from one side, and propagates gradually along the contour of ice while at the same time spreading rapidly towards the center. Compared with other icephobic methods, such as expensive and vulnerable micro/nano-surfaces or functional composite coatings, this low-cost and environment friendly device appears promising for large-scale deicing applications in various engineering fields.

Investigating the Compressive Strength Properties of Concrete Using Some Common Ghanaian Ordinary Portland Cements

In a general sense, concrete is made of cementitious material, aggregates and water but the mix productivity is one issues that affect the amount of strength concrete developed. The concrete mix productivity is a direct function of the amount and quality of the cementitious material. The commonest cementitious material used for concrete in Ghana like other countries in the world is the Ordinary Portland Cement. The research sort to investigate the compressive strength properties of concrete made from some common Ghanaian Ordinary Portland Cement brands mostly used in the countries construction industries. The research strategy adopted was experimental. The research was a cross –sectional studies and used laboratory tests to get information on all cements. Cement grade 42.5N, 42.5R and 32.5R were used. A total of one – hundred and eight (108) concrete cubes were made from nine different brands of Ordinary Portland Cement with a mix design of 1:2:4. No admixtures were used in the mix. It was established that, Ordinary Portland Cement Brand E of grade 42.5R has the highest compressive strength after 28 days. Some of the cement brand with grade 32.5R developed better strength than that of grade 42.5R. Based on the experiment conducted, it can be concluded that for the C15 (1:2:4) and C20 compressive strength as per IS 456:2000, Ordinary Portland Cement Brand E and G of grade 42.5R and Ordinary Portland Cement Brand H and J of grade of 32.5R satisfactory meets the requirement. It implies that some of the Ghanaians Portland Cement developed a satisfactory compressive strength and meets the minimum strength attainment after 28 days’ which is 15 N/mm2. Based on the result, it is recommended that Ordinary Portland Cement Brand E of grade 42.5R should be used for most concrete production and Ordinary Portland Cement Brand J of grade 32.5R can also be used for concrete work in the absence of E 42.5R.&#x0D; &#x0D; Citation: Akorli, K. S., Danso, K., Ayarkwa, J. and Acheampong, A. (2021). Investigating the Compressive Strength Properties of Concrete Using Some Common Ghanaian Ordinary Portland Cements.&#x0D; International Journal of Technology and Management Research (IJTMR), Vol. 6 (1): Pp.154-166.[Received: March 13, 2021Accepted: September 1, 2021

Continuous Improvement in the Development of Cold Agglomeration Process to Add Value to Manganese-rich Waste Streams

World-Class Organisations strive to move away from linear economy to circular economy, where fundamental objectives are to eliminate waste and continual utilisation of resources. Circular economy and sustainability is also critical to the mining industry. Manganese mining operations and the smelting industry inherently generate Manganese rich by-products that are not saleable due to their small particle size. The bulk source of fine-sized by-products being evaluated are bag-house dust collected during smelting (below 100 microns), and ultra-fines (slimes) generated during beneficiation of the ore (below 300 microns). Other sources of fines are, among others: bag-house dust collected from conveyor systems and metal crushing and screening (below 100 microns), fines generated upon metal crushing (-3mm)) and fines from Metal Recovery Plant (-3mm). These waste streams are traditionally accumulated in lined tailings storage facilities that require continuous management to reduce environmental risk. In 1998, Assmang Manganese took an informed decision to investigate different ways on how to re-use such by-products. This paper firstly summarizes Assmang Cato Ridge experience in developing and identifying the most efficient, effective and flexible cold agglomeration process that can add value to Manganese rich waste streams. Such development aims to increase the utilization of waste streams, through agglomeration of current arising and historical furnace dust and other by-products generated during smelting operation, as well as the manganese ultra-fine ore generated at Assmang Manganese Mines. The paper examines four different cold agglomeration processes (Block or Brick-Making, Roll Press, Extrusion and High Compression-Vibration) that have been trialled by Assmang over the years. A High Compression Vibration cold-agglomeration technology, currently in use by Cato Ridge, has demonstrated unique capabilities to achieve competent agglomerates that meet critical metallurgical requirements. The use of agglomerates has become a significant part of the burden charge in the production of HCFeMn in Submerged Arc Furnaces (SAF) at Cato Ridge. The physical characteristic of agglomerates that Cato Ridge targets to feed its SAF charging bins are: maximum 10% fines below 6.0mm, minimum Shatter Index of 93% and minimum Compressive Strength of 5.0 MPa. The critical chemical composition required is Manganese content of 37% and Manganese to Iron ratio of 5.5.

Mechanical properties of porcelain waste alkali-activated mortar

Natural sand is extensively used in mortars and concretes as aggregate, and the consumption of this material in construction activities is leading to depletion. This study investigated the use of porcelain waste (PW) that comes from the electrical insulator industry as a replacement of sand in alkali-activated mortar (AAM) production. NaOH and rice husk ash were used to make a sodium silicate which was used as alkali activator, and metakaolin was the aluminosilicate source. Some properties of AAM were evaluated (e.g., workability, compressive and flexural strengths). Results indicated AAM made with PW developed minimum compressive and bond strengths at 28 days of 34 MPa and 1.4 MPa, respectively. PW showed to be a good material to replace natural sand in AAM production, which makes it a feasible alternative to the final disposal of PW generated by electrical insulators industries.

Investigation of waste clay brick as partial replacement of geopolymer binders for rigid pavement application

Waste clay brick (WCB) is identified as a feasible alternative cementitious material for producing geopolymer binders to replace ordinary Portland cement (OPC). This study investigated mechanical properties and environmental impacts of one-part geopolymer binders at ambient curing conditions, employing binary blends of WCB with fly ash or slag, while using anhydrous solid sodium metasilicate as the sole activator. WCB was replaced separately with fly ash and slag at 20%, 40%, 60% and 80% by mass to obtain the aluminosilicate precursors. Combination of the aluminosilicate precursors and the solid activator was considered as the total binder. The effect of the alkali activator content, particle size and water-to-binder ratio on compressive strength development were investigated. The strengths of the geopolymers were compared with minimum concrete strength requirements indicated in Australian pavement design guidelines and American Association of State Highway and Transportation Officials (AASHTO) guidelines. The experimental results indicated an optimum activator content of 10% by mass of the total binder for all binary geopolymer systems. Compared to WCB alone and WCB-fly ash blends, binary geopolymer systems of WCB-slag blends showed higher compressive strengths. WCB-slag blends showed high early strength gain and achieved more than 22% and 48% of its corresponding 28-day strength within 24 h and 72 h, respectively. Highest 28-day compressive strength of 81.8 MPa was achieved for the binder with 40% WCB and 60% slag in the precursor. The strength further improved to 96.8 MPa by reducing WCB particle size from 150 µm-passing to 75 µm-passing. Additionally, the environmental impacts associated with the different blends were evaluated considering carbon dioxide emission and energy consumption during their production. These values were subsequently compared with those of OPC manufacturing. The comparison showed that WCB based geopolymer binders can reduce carbon emissions up to 78% and energy consumption up to 85%.

Assessment of acid resistance of natural pozzolan-based alkali-activated concrete: Experimental and optimization modelling

Although the synthesis and properties of natural pozzolan (NP)-based alkali-activated binder (AAB) have been investigated, to the best of our knowledge, no study has focused on and assessed the performance of such concrete when exposed to acid attack. In addition, there is a lack of information regarding the optimisation of reaction parameters. Therefore, in the present study, NPs blended with nano-silica (nSiO2) from 0 to 7.5% were taken into account to develop alkali-activated concrete (ACC), cured at room temperature, and subsequently exposed to 5% sulfuric acid (H2SO4aq). The performance of the NP/nSiO2-based ACC was evaluated by visual examination, microstructure, weight loss, and compressive strength loss up to one year of exposure to an acidic environment. In addition, artificial neural network (ANN) and response surface methodology (RSM) models were developed to predict and optimize nSiO2 to ascertain the minimum weight and strength loss. Based on both the predicted and actual results, a significant improvement in the microstructure was achieved with an increase in nSiO2. The micro-analytical examination revealed the leaching of vital elements from the binder structure, such as Al, Ca, and Na, which enabled the creation of highly expansive substances such as gypsum, which caused cracking and eventually disintegration in the OPC and NP-based AAB incorporating lower quantities of nSiO2. Both the loss in weight and strength were in the range of 23%–39% in the 1% to 7.5% nSiO2 modified AAC. In contrast, in the control AAC and OPC-based concrete, a weight loss of more than 50% was recorded, along with a substantial reduction in strength.

A New Method to Calculate the Fluxgate Magnetometer Offset in the Interplanetary Magnetic Field: 2. Using Mirror Mode Structures

AbstractAccurate magnetic field measurement is of great significance to the development of space exploration. The fluxgate magnetometer (FGM) is a magnetic field measuring instrument commonly used on the spacecraft. The zero offset of the spaceborne FGM varies slowly with time, thus it needs to be regularly calibrated. Here, we develop a new method to determine the zero offset of the FGM using mirror mode structures. This method is based on an assumption that the magnetic depression of mirror mode structures is only in the maximum variance direction. We find that each mirror mode structure has an optimal offset line (OOL), which is determined by the minimum strength of the modified magnetic field in the plane perpendicular to the maximum variance direction in an offset cube. The OOL is approximately parallel to the maximum variance direction and passes through the zero offset in the offset cube. The common intersection of at least two non‐parallel OOLs can be regarded as the zero offset, which accuracy tends to be higher with more events. Our method can simultaneously use the mirror modes and Alfvén waves, and is able to be applied to many regions, such as solar wind, planetary magnetosheaths and magnetospheres.

Properties of Engineered Cementitious Composites with Raw Sugarcane Bagasse Ash Used as Sand Replacement

This study investigates the effects of raw sugarcane bagasse ash (SCBA) used as a partial or complete replacement for silica sand in engineered cementitious composites (ECCs). ECC mixtures with five different replacement levels of sand with SCBA were produced (i.e., 0%, 25%, 50%, 75%, and 100% by volume). The SCBA utilized in this study was comprehensively characterized. Furthermore, the fresh and hardened properties of the produced ECC materials were thoroughly evaluated. The characterization of SCBA revealed that raw SCBA consisted mainly of small (i.e., 256 μm average particle size), porous, and irregularly shaped particles with carbon and silica as the main constituents. Furthermore, the SCBA met the pozzolanic component requirement for Class C pozzolans; however, it did not meet the minimum strength activity index requirement to be classified as a pozzolan; however, it did not meet the minimum strength activity index requirement to be classified as a pozzolan. In terms of ECC fresh properties, the incorporation of SCBA produced an important loss in workability, which was mitigated with increasing dosages of high-range water reducer for increasing amounts of SCBA, which also resulted in a substantial increase in the air content. In the case of hardened material properties, the incorporation of SCBA as sand replacement produced a slight decrease (up to 11%) of the compressive strength of ECCs. However, the tensile strength and especially the tensile ductility of the composites were substantially enhanced (up to 22.3% and 311%, respectively). The tensile strength improvements were credited to the pozzolanic and/or filler effect of SCBA. On the other hand, enhancements in the tensile ductility were associated to the combined effect of the reduction of crack-tip matrix toughness (credited to the decrease in aggregate particle size), reduction in ECC cracking strength (due to increase in air content), and increase in the complementary energy (attributed to the potential decrease in the chemical bond of the fiber/matrix interface and an enhanced fiber dispersion). The surface resistivity of ECC materials was negatively affected by the addition of SCBA. Furthermore, the length change of all SCBA-ECC materials, at all ages of curing, was higher in comparison with that of the control mixture, except for the mixture with 25% replacement at 28 days of curing.

Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

Experimental Study on Partial Replacement of Materials like Industrial Waste &amp; Rice Husk with Clay Mortar

Abstract: Ancient peoples were used mud mortar for their stone houses. The result was a stone home that was both solid and warm and lasted for lifetimes. Mud made houses creates wonderful warm houses as compared to concrete made houses. In the history of construction, clay mortar was followed by lime mortar. Cement manufacturing is one of the major contributors in global warming and climate change. Also fine aggregate is the natural resource and it is limited in nature, thus industrial sand can be alternative for fine aggregate. We are going to use PPC cement because PPC cement resist sulphate attack more than OPC cement and also it is quite cheap. The setting time of the PPC cement is more than OPC cement but when it settled completely then it gives more strength more than OPC cement. Also they used river sand in there project and nowadays there is shortage of river sand that’s why we are going to use foundry sand partially replacement with sand. Foundry sand is a industrial waste sand so we can save money by using foundry sand. The mortar with the alternative fine aggregate, mixed with different combinations of binding materials. We take White clay to River sand proportion as 1:1. In that we partially replace white clay with PPC cement and in other hand River sand partially replaced with Industrial waste(Foundry sand) and also with Rice husk and that mix proportions was tested for 28 days Compressive strength &amp; after curing of 28 days ,cubes cured in acid &amp; alkali solution for Durability strength. The mortar with 20% PPC cement + 80% white clay &amp; 40% foundry sand + 60% river sand (proportion of white clay to river sand is 1:1) has compressive strength in the range of 4.38MPa (Compressive strength) &amp; 4.42Mpa (Compressive strength after Durability test) and these mixes compared with 1:6 conventional mortar proportion, which is acceptable as per the IS code 2250-1981 specification, the minimum strength requirement of mortar to be 3 MPa. Therefore, the use of stabilized mud mortar in construction would prove to be sustainable as well economical. Keywords: Mud mortar, Foundry sand, PPC cement, Compressive strength, Durability test.

Improving Marine Concrete Performance Based on Multiple Criteria Using Early Portland Cement and Chemical Superplasticizer Admixture.

This study sought to examine the performance design of concrete mix proportions to ensure chloride resistance and early strength with respect to C35 (35 MPa), which is the minimum compressive strength class of concrete used in a marine environment. For the proposed concrete mixture, C24 (24 MPa) was selected and binders for concrete were manufactured using a blend of OPC (ordinary Portland cement), EPC (early Portland cement), and GGBS (ground granulated blast-furnace slag). The results of the experiment confirmed that the combined use of EPC and GGBS greatly improve the early-strength development and chloride resistance of concrete. An analysis revealed that the time for removal of forms can be reduced by 5–9 h from the aspect of early concrete strength. Moreover, in terms of construction productivity, EPC and GGBS were reduced by up to 16.39 h/cycle compared to other concretes. Regarding economic and environmental impacts, EPC and GGBS were more effective than C35 concrete. This study is significant as its findings help make it possible to examine the most economical concrete mix design in relation to strength development according to the application of EPC, GGBS, and PC-based admixtures.

Novel platinum bipolar electrode for irreversible electroporation in prostate cancer: preclinical study in the beagle prostate

The exposure of the prostate to high electric field strength during irreversible electroporation (IRE) has been extensively investigated. Multiple monopolar electrodes, however, have risks of organ piercing and bleeding when placing electrodes. A novel bipolar electrode made of pure platinum and stainless steel was developed for prostate cancer ablation. Voltages of 500 and 700 V were applied to the beagle prostate with this electrode to evaluate ablated tissues and their characteristics. IRE procedures were technically successful in all dogs without procedure-related complications. The current that flowed through the anode and cathode while applying 500 and 700 V were 1.75 ± 0.25 A and 2.22 ± 0.35 A, respectively. TUNEL assays showed that the estimated ablated areas when applying 500 and 700 V were 0.78 cm2 and 1.21 cm2, respectively. The minimum electric field strength threshold required for induction of IRE was 800 V/cm. The platinum electrode was resistant to corrosion. The IRE procedure for beagle prostates using a single bipolar electrode was technically feasible and safe. The novel bipolar electrode has great potential for treating human prostate cancer with fewer IRE-related complications.

Experimental study on mechanical properties, hydration kinetics, and hydration product characteristics of aeolian sand paste-like materials

Using fly ash (FA), aeolian sand (AS), cement, and mixing water as filling materials for making the paste-like filling mining can not only effectively control the surface subsidence and solve the “three-underground mining” coal pressure but also solve the environmental problems caused by the solid wastes, so as to realize the sustainable utilization of solid waste. The utilization of a large amount of AS resources can control land desertification, and the sale of aeolian sand can bring considerable economic benefits to Yuyang district. Hence, in this study, different ASPM samples were produced by varying the content of FA (0–30 wt%) and the curing times (3, 7, 14 and 28 days). The mechanical strength test, hydration kinetics test and microscopic test of aeolian sand paste-like materials (ASPM) was studied. The results showed that, according to the typical underground mining, the uniaxial compressive strength (UCS) of the backfill, cured for 28 days, was generally between 0.7 and 2.0 MPa, which can provide good roof support. In this study, the minimum strength of the ASPM reached 4.43 MPa (C-FA0), so the ASPM met the requirements of strength performance. Secondly, the hydration exothermic process of ASPM was divided into five different stages, and the influence of FA content on hydration kinetics was analyzed. For example, in the acceleration stage of ASPM, there was a positive correlation between the FA content, exothermic heat, and exothermic rate. The possible reason was that the particle size of FA was finer than that of AS, and the hydration reaction was more sufficient. In addition, the microscopic morphology and the characteristics of hydration products of ASPM were also studied. It is an important prerequisite for industrial field practice to study the mechanical properties, hydration characteristics and hydration product of ASPM.

Shear strength model and prediction of failure mode for multi-spiral column

The damage of reinforced concrete columns due to shear is often serious, so this type of failure should be avoided from the design. In this paper, a model derived based on the discrete computational method is proposed to calculate the shear strength of column carried by multi-spiral transverse reinforcement, accounting for the effect of compression depth. Furthermore, based on this model, a method is proposed to predict the failure mode of multi-spiral columns. The test database of multi-spiral columns from previous studies is used to validate both the shear strength and failure mode predictions. The proposed model with a crack angle of 40 degrees gives the best estimation of the shear strength of multi-spiral columns, and the proposed method predicts well the failure mode of these columns. To avoid shear failure, the ratio of the minimum shear strength calculated from the proposed model with a crack angle of 40 degrees to the shear force based on the moment-curvature analysis is suggested to be larger than 1.2.

Effect of Adding Zeolitic Tuff on Geotechnical Properties of Lime-Stabilized Expansive Soil

This study aims to evaluate experimentally the potential of expansive soil stabilization using different additives: zeolitic tuff (ZT), lime, and a combination of lime and ZT. Four different percentages of ZT (10%, 20%, 25%, and 30%), three percentages of lime (2%, 4%, and 6%), and variable percentages of their combinations were used to stabilize the soil for pavement subbase application. Atterberg limits, pH, compaction, linear shrinkage, swelling, unconfined compressive strength (UCS), and California bearing ratio (CBR) tests were performed on treated and untreated soil specimens at different curing times. Results showed that ZT additives effectively reduced the plasticity, linear shrinkage, and swell potential in addition to increase the maximum dry unit weight, UCS, and CBR. The results of this study were supported by a microstructural analysis using scanning electron microscopy (SEM) associated with the energy-dispersive X-ray spectroscopy (SEM/EDX) technique. It was determined that the UCS and CBR values for the 4% lime stabilized soil increased by 22% and 70%, respectively, after the addition of 25% ZT. Based on evaluation of the results, an optimum mixture of 25% ZT and 4% lime stabilized soil can be used in pavement subbase applications as it achieved the minimum strength target.

Formulation and Evaluation of Poly Herbal Liqui-Solid Compact for its Anti-Inflammatory Effect

Liquisolid approach is a potential method due to the ease in the production process, low cost, and manufacturing process because of their strong flow and compaction properties. The study's main goal is to create a liquisolid powder formulation from the polyherbal extract and evaluate its anti-inflammatory activity. Hibiscus cannabinus, Murraya koenigii, and Tabernaemontana divaricate are used to formulating polyherbal Liquisolid powder formulation to assess their anti-inflammatory action. The formulation is tested for its stability studies and anti-inflammatory activity, both in-vitro and in-vivo. The polyherbal liquisolid powder formulation (F5) has a minimum strength of 1kg/cm 2, while F2 &amp; F6 strength was 4 kg/cm2; FTIR studies showed no interactions between drug and excipients. To confirm the liquisolid powder formulation, further evaluations on friability, hardness, disintegration time, dissolution rate, and Differential scanning calorimetry and X-ray powder diffraction analysis were determined. The polyherbal extract's anti-inflammatory activities were evaluated using the paw edema and cotton pellet method, and the results are found to exhibit its inhibitory activity. The polyherbal extract of Liquisolid powder formulation was evaluated, and it showed a promising inhibitory activity to overcome the inflammation in the test species. Hence it can be used as an alternative therapy for curing inflammation.