Percentage Of Aggregates Research Articles

A new strategy of using periphyton to simultaneously promote remediation of PAHs-contaminated soil and production of safer crops

Contaminated farmland leads to serious problems for human health through biomagnification in the soil-crop-human chain. In this paper, we have established a new soil remediation strategy using periphyton for the production of safer rice. Four representative polycyclic aromatic hydrocarbons (PAHs), including phenanthrene (Phe), pyrene (Pyr), benzo[b]fluoranthene (BbF), and benzo[a]pyrene (BaP), were chosen to generate artificially contaminated soil. Pot experiments demonstrated that in comparison with rice cultivation in polluted soil with ΣPAHs (50 mg kg−1) but without periphyton, adding periphyton decreased ΣPAHs contents in both rice roots and shoots by 98.98% and 99.76%, respectively, and soil ΣPAHs removal reached 94.19%. Subsequently, risk assessment of ΣPAHs based on toxic equivalent concentration (TEQ), pollution load index (PLI), hazard index (HI), toxic unit for PAHs mixture (TUm), and incremental lifetime cancer risk (ILCR) indicated that periphyton lowered the ecological and carcinogenicity risks of PAHs. Besides, the role of periphyton in enhancing the rice productivity was revealed. The results indicated that periphyton alleviated the oxidative stress of PAHs on rice by reducing malondialdehyde (MDA) content and increasing total antioxidant capacity (T-AOC). Periphyton reduced the toxic stress of PAHs on the soil by promoting soil carbon cycling and metabolic activities as well. Periphyton also improved the soil's physicochemical properties, such as the percentage of soil aggregate, the contents of humic substances (HSs) and nutrients, which increased rice biomass. These findings confirmed that periphyton could improve rice productivity by enhancing soil quality and health. This study provides a new eco-friendly strategy for soil remediation and simultaneously enables the production of safe crops on contaminated land.

Comparative Study of Destructive Method and Non-destructive with Ultra-Sonic Pulse Velocity Method

The appropriate percentages of cement, fine aggregates, coarse aggregates, and water are utilized to make concrete. Due to its relatively low price and widespread availability, it is a ubiquitous building material. Concrete in its fresh state can also be molded into any desired shape and size. Strength and durability are two of concrete’s most important characteristics (particularly when used for structural purposes). Verify the concrete’s compressive strength before placing it under the expected loads. NDT methods, both destructive and non-destructive, can be used to assess the compressive strength of hardened concrete. A non- destructive test does not harm the concrete specimen, whereas a destructive test (DT) crushes the cast specimen until it breaks. In non-destructive testing, materials, components or assemblies are inspected, tested or evaluated without destroying their serviceability. This study compares the compressive strength of concrete utilising an ultrasonic pulse velocity approach, which is both destructive and non-destructive. Concrete cubes measuring 150 mm by 150 mm by 150 mm were created using the concrete mix grades 25N/mm2 and 30N/mm2, and they were allowed to cure for 28 days. There were 12 cubes produced and used for the study. The determine compressive strength between destructive and non -destructive (ultra-sonic pulse velocity) test method.

The Use of Basaltic Rock as An Aggregate in Concrete

The purpose of this research is to investigate the adequacy according to Civil Engineering Standard of using basalt aggregates in concrete mixes. Basalt aggregates which are an extrusive igneous rock has gained significant development due to its properties and availability in Biu. The researcher examines the aggregate gradation, rate of water absorption, density, workability of the basalt aggregate and determination of compressive strength of the concrete cubes after 7days, 14days and 28 days of curing which is backed up by a statistical analysis of the model in the concrete mix by varying the percentage of basalt aggregate. Meanwhile a conventional limestone mix was used as control mix. The results of this investigation show a general improvement in the mix properties as a result of introducing Biu Borno State basalt aggregates in the mix design.

Utilization of Waste Aggregate for Aggregate Construction for Improvement of Soil Bearing Capacity

Soil bearing capacity is one of the important elements when designing the foundation, bridges, and embankment. The soil bearing capacity needs to be improved due to the weak soil such as clayey silt or silty clay soil that was encountered at the construction site. There are many stabilizations method such as bio treatment of the subgrade, chemical stabilization method, chemical grouting or injection systems, aggregates, or reuse of the waste materials, geosynthetic reinforced embankment and vibro compaction. One of the most common chemical stabilization methods is by using additives to improve soil strength. There are a few wastes material that can be used for strengthening clay soil which is more economic and environmentally friendly. The objective of this research is to improve the soil engineering parameters and bearing capacity using Recycled Waste Aggregates (RWA). In this study, soil samples will be added with different percentage weight of RWA and undergo a few series of laboratory experiments to study its behavior which will be sieve analysis, specific gravity, compaction, and California Bearing Ratio (CBR). The optimization of the percentage of recycled concrete aggregates can be determined from the simulation method. For bearing capacity value, the increase of bearing capacity greatly increases as the percentage of RCA increased and the optimum percentage of RCA is 15%. It concluded that the increasing value of RCA will improve the strength and soil subgrade structures. Recycled Concrete Aggregates have a really great potential material to be used in engineering.

Evaluation of single particle morphological characteristics and human health risks in different functional areas

Purpose This study aims to better understand the morphological characteristics of single particle and the health risk characteristics of heavy metals in PM2.5 in different functional areas of Handan City. Design/methodology/approach High resolution transmission electron microscopy was used to observe the aerosol samples collected from different functional areas of Handan City. The morphology and size distribution of the particles collected on hazy and clear days were compared. The health risk evaluation model was applied to evaluate the hazardous effects of particles on human health in different functional areas on hazy days. Findings The results show that the particulate matter in different functional areas is dominated by spherical particles in different weather conditions. In particular, the proportion of spherical particles exceeds 70% on the haze day, and the percentage of soot aggregates increases significantly on the clear day. The percentage of each type of particle in the teaching and living areas varied less under different weather conditions. Except for the industrial area, the size distribution of each type of particle in haze samples is larger than that on the clear day. Spherical particles contribute more to the small particle size segment. Soot aggregate and other shaped particles contribute more to the large size segment. The mass concentrations of hazardous elements (HEs) in PM2.5 in different functional areas on consecutive haze pollution days were illustrated as industrial area > traffic area > living area > teaching area. Compared with the other functional areas, the teaching area had the lowest noncarcinogenic risk of HEs. The lifetime carcinogenic risk values of Cr and As elements in each functional area have exceeded residents’ threshold levels and are at high risk of carcinogenicity. Among the four functional areas, the industrial area has the highest carcinogenic and noncarcinogenic risks. But the effects of HEs on human health in the other functional areas should also be taken seriously and continuously controlled. Originality/value The significance of the study is to further understand the morphological characteristics of single particles and the health risks of heavy metals in different functional areas of Handan City. the authors hope to provide a reference for other coal-burning industrial cities to develop plans to improve air quality and human respiratory health.

The usage of marginal aggregate as subbase layer

Aggregate holds the main role in determining the quality of pavement layers. Unfortunately, the locally available aggregates sometimes did not pass one or more requirements stated in the standard, making these aggregates technically unable to be used. These aggregates are called marginal or substandard aggregates. However, previous research projects have shown the potential of utilizing marginal aggregates as pavement layers. This research aims to analyst the techniques for utilizing marginal aggregates as pavement layers, specifically as subbases. Two techniques were evaluated herein, namely by varying the aggregate gradation and by adding cement and lime as stabilizers, and the specimens were assessed by the California Bearing Ratio (CBR) test. The research results found that varying the percentage of coarse and fine aggregates in the specimens improved the CBR value. The specimen obtained the highest CBR value with 70% coarse aggregate and 30% fine aggregate. Moreover, it was found that adding cement and lime as stabilizers at the right percentage was also able to improve the CBR value of the specimens and mixing the stabilizers beyond a certain percentage decreases the CBR value. The amount of cement and lime needed depended on the aggregate gradation used.

Mechanical properties, attenuation coefficient, and microstructure of ultra high-performance heavyweight concrete for radiation shielding applications

This paper explores the characteristics of ultra-high-performance heavyweight radiation shielding concrete by using many types of radiation-resistant aggregates. The experimental work is carried out in two groups, The first group contains six mixes that are prepared by using barite, basalt, and serpentine as heavyweight coarse aggregate, and the second group contains six mixes that are prepared by using the same percentages of coarse aggregate in the first group while partially replacing the fine aggregates with hematite. The main research aim is to study radiation absorption characteristics using 60Co sources that discharge 1.25 MeV photons. Linear attenuation coefficient, half-layer value, and tenth-layer value layers were assessed as radiation absorption characteristics. In addition, the hardened characteristics of all mixes like compressive, tensile, flexural strengths, and modulus of elasticity have been investigated, also, microstructure has been tested. Based on the results, The density of mixtures ranged between 2690 and 3080 kg/m3. The largest value of concrete density was recorded for barite with hematite. Although basalt with hematite gave the maximum compressive strength value of 155.8 MPa. Barite with hematite improved the radiation protection properties compared to basalt with sand by 20 % as the Linear attenuation, HVL, and TVL values became 0.173 cm−1, 4.01 cm, and 13.28 cm respectively.

Environmentally friendly concrete material with early strength and fast hardening using coal as an aggregate: a case for supporting empty roadways

In order to facilitate ventilation or transportation, many coal mines usually excavate an empty roadway in the middle of the mining working face. Under the influence of mining pressure, empty roadways are easily damaged, seriously threatening coal mines’ safety. Because the traditional support method of the empty roadway has the problems of low efficiency, high cost, and low strength, this paper researches the coal-based concrete support material with better effect. The grading test of coal aggregate was carried out, and it was found that the percentage of small-size aggregate greatly influenced the reduction of aggregate porosity in the stacked state. To solve the problems of the high cost of strengthening support methods such as high water material support in empty roadways, which could be more conducive to recovery and reduce coal quality. The research on empty roadways supports concrete material with coal as aggregate, making the working face recover coal resources safely and efficiently. The optimum gradation test of the total is to enhance the strength of support and solve the problem of low power and difficult cementation of coal. Based on the hydration analysis of cementitious material, the coal-based concrete, mainly composed of low-cost slag, is determined. The cementitious material with simple composition, rapid setting, and fast hardening was found. It is proved that the mechanical properties and molding effect of coal-based concrete support composed of gypsum, GGBFS, and clinkercement are better than those of commercial cement. The structural model of “surrounding rock-empty roadways-coal pillar-support” is established. The calculation method and check basis of empty roadways support resistance N1 are obtained. The results of industrial application verified that coal-based concrete could effectively protect empty roadways without affecting the productivity of coal mines.

Mussel shell mortars durability: Study of aggregate replacement limit

The knowledge acquired through previous experimental phases with coating mortars with mussel shell aggregates led to conclude that irregular, flaky and hydrophobic particles of the mussel shell and the organic matter content introduce entrapped air and entrained air in the mixes. This phenomenon causes different and opposite effects on the main properties of mortars, which are in some way positive and negative (for durability), consequently, their durability cannot be easily predicted. The present work pretends to analyse the results of different durability tests, such as water vapour permeability, adhesive strength, and weathering cycles to recommend the maximum percentage of mussel shell sand used in coating mortars that guarantee the required lifespan.After an in-depth literature review, it can be said that it is not easy to predict the durability of mortars using mussel shell aggregates. This question has been hardly analysed in the existing literature and the maximum substitution percentage of conventional aggregate that can be replaced is not clear. This work aims to answer this issue by analysing different properties: water vapour permeability, adhesive strength, and weathering cycles. Mussel shell content improves the water vapour permeability of both air lime and cement mortars but worsens the adhesive strength and weathering cycle behaviour. For most applications, 25 % of mussel shell aggregate can be employed, but for some applications, 50 % or even 75 % of mussel shell aggregate is feasible and will avoid the undesirable landfilling of this waste.

Experimental investigation of the behavior of concrete beams containing recycled materials reinforced with composite rebars

The application of various Fiber Reinforced Polymer (FRP) composite materials is very widespread in the world. The use of recycled materials in concrete, can improve some of the mechanical properties of concrete. In this laboratory research, the behavior of reinforced concrete beams with composite rebars with glass fibers made of concrete containing recycled materials such as glass, rubber and micro-silica with different mixing plans has been investigated. These mixing plans are such that recycled glass and rubber aggregates have replaced a percentage of fine and coarse concrete aggregates, and glass powder and micro-silica have also replaced a percentage of concrete cement. The results showed that the replacement of coarse rubber, glass powder, and micro-silica in concrete materials increases the bending strength and ductility of concrete beam. In examining the microstructure of concrete by Scanning Electron Microscope (SEM) the adhesiveness of the rubber Interfacial Transition Zone (ITZ) in concrete was suitable.

Study On Effect Of Marble Powder And Waste Foundry Sand As Fine Aggregates On The Properties Of Metakaolin-Cement Concrete

To bring an challenging and acceptable change in construction industry, upcoming graduates have to be much aware of alternate materials to be used in conventional concrete with improved performances and this study can be an encouraging approach to them. Many research studies have investigated the possible use of industrial by-products such as fly ash from thermal power plants, red mud from aluminium manufacturing industry, copper slag from copper smelting industry, GGBS from steel industry, and waste foundry sand from metal casting industries in cement concrete production. Here, it is investigated on the possibility of utilizing two industrial by-products in the production of concrete for achieving sustainable development. Metakaolin is used for replacing a specific percentage of cement, and waste marble powder and waste foundry sand are used to replace different percentages of conventional fine aggregates (sand) for producing a sustainable concrete. It is observed from the results that properties of cement concrete are influenced by the percentage content of metakaolin, waste marble powder and waste foundry sand.

Utilization of recycled concrete aggregates for pavement base courses – A detailed laboratory study

Pavement construction and maintenance have become prevalent globally due to increasing traffic volumes and higher vehicular axle weights, driven by population growth and technological advancements. However, the extensive reliance on natural resources raises concerns about their long-term availability and sustainability. An emerging trend in construction involves the application of alternative materials, such as demolished waste and industrial by-products, as substitutes for natural materials like aggregates. This study examined strength properties, including unconfined compressive strength (UCS), flexural strength, elastic modulus, indirect tensile strength (ITS) and the performance aspects of durability, shrinkage, and fatigue. Cement stabilized recycled concrete aggregate (CSRCA) mixes were prepared by varying the percentage of natural coarse aggregate (NCA) and recycled concrete aggregate (RCA) from 0% to 100% and cement content from 3% to 7%. The experimental findings demonstrated that the cement content had a more significant impact on the strength and performance characteristics of CSRCA mixes than RCA content. The mixes with RCA replacement up to 50% and a cement content of 5% satisfy the strength and durability criteria recommended by IRC 37. A higher proportion of RCA was found to have a detrimental effect on mechanical properties and fatigue characteristics. It was found that the CSRCA mixes with 50% RCA replacement to NCA can be used as a base layer instead of a conventional cement-treated base (CTB) for flexible pavement.

High rates of high on-aspirin platelet reactivity in patients after transcatheter aortic valve implantation

Abstract Background Guidelines recommend aspirin monotherapy in patients after transcatheter aortic valve replacement (TAVR) without an indication for oral anticoagulation. The prevalence of high on-aspirin platelet reactivity (HAPR) varies from 1% to 34% and may be associated with long-term ischemic risk or subclinical valve thrombosis which occurs in 17-40% of the patients after TAVR. Purpose To determine the prevalence of HAPR and its association with subclinical valve thrombosis in patients undergoing TAVR using methods that directly indicate the degree of platelet cyclooxygenase inhibition. Methods Data were collected in a prospective, single-center, observational cohort study between October 2020 and June 2022. Patients were enrolled after TAVR, and platelet function was assessed during the hospital stay with light-transmittance platelet aggregation (LTA) and thrombelastography (TEG) platelet mapping. Platelet aggregation was induced with arachidonic acid (AA)-induced LTA (final concentration [fc] 1.64 mM) and TEG (fc 1.0mM). The maximum percent aggregation (%aggr) was recorded. According to the literature, HAPR was defined as >20% aggregation by LTA or >50% aggregation by TEG, respectively. All patients were under maintenance of 100 mg aspirin or received a loading dose of 300-600mg aspirin before measurement. 47 of 75 patients underwent computed tomography (CT) to detect valve thrombosis (VT) 6 months after TAVR. Results Data from 75 patients under maintenance of aspirin were analyzed. The median age was 82 years (interquartile range, IQR 79-85), and 52% were male. 12 patients (16%) had a history of stroke or TIA, and 7 (9%) had suffered a previous myocardial infarction. TEG and LTA were performed during the hospital stay between days 0 and 17 post-TAVR. Median AA-induced maximum aggregation by LTA was 17 % (interquartile range, IQR 13-38) and by TEG was 29 % (IQR 5-64). When determining platelet function using LTA, 33 patients (44%) had residual platelet function (i.e., %aggrLTA >20%) despite aspirin treatment. According to the TEG results, 27 patients (36 %) were identified as HAPR (i.e., %aggrTEG >50%). The agreement (Kappa=0.06) and correlation (r=0.32, Figure 1) between the two tests were low to moderate. 13 patients had HAPR in both methods. 19 of 47 patients (40%) had VT on CT 6 months after TAVI. 12 of these 19 patients (63%) with VT responded well to aspirin in the TEG and LTA, while 7 (37%) had HAPR in both tests. HAPR was not significantly associated with HALT when measured with TEG or LTA (OR 0.90 [95% CI 0.27.2.76], p=0.86 and 0.58 [95% CI 0.17-2.04], p=0.37, respectively; Table 1). Conclusion HAPR assessed by LTA and TEG is frequent in patients undergoing TAVR. In this exploratory study, HAPR was not significantly associated with the occurrence of HALT. Further studies are required to evaluate the long-term risk of leaflet thrombosis or thromboembolic events in patients with HAPR.

MECHANICAL PROPERTIES OF SUSTAINABLE FIBER-REINFORCED LIGHTWEIGHT AGGREGATE CONCRET

With the rapid growth of high-rise buildings and large-scale structures, there is a need to preserve natural resources and reduce loads on buildings by using lightweight concrete to achieve better performance for structures. In the study, four groups were prepared; the first group included one mix containing natural aggregate, and the second mix replaced all the natural aggregates with lightweight pumice aggregates. These mixes are reinforced with carbon fiber with a 0.5% volume fraction. In the second group, a variable volume fraction of carbon fiber of (0.0 and 1%) of mixes. In the third group, the mixes have different lengths of carbon fiber (20mm, 30mm) and a volume fraction of carbon fibers 0.5%. Finally, the fourth group partially replaces sand as a variable with a percentage of lightweight fine aggregates (10% and 30%) reinforced with fibers. Adding carbon fibers to the concrete specimens by 0.5% and 1% improved splitting tensile strength and flexural strength compared to the specimens containing carbon fibers with a length of 5mm. Also, enhanced samples containing fibers by 0.5% and lengths of 20 mm or 30 mm, compared to the sample containing carbon fibers with a length of 5 mm. Also, the specimens containing lightweight fine aggregates as a replacement with a percentage of sand have a lower splitting tensile strength and flexural strength than the reference mix.

Bio-inspired based meta-heuristic approach for predicting the strength of fiber-reinforced based strain hardening cementitious composites

A recently introduced bendable concrete having hundred times greater strain capacity provides promising results in repair of engineering structures, known as strain hardening cementitious composites (SHHCs). The current research creates new empirical prediction models to assess the mechanical properties of strain-hardening cementitious composites (SHCCs) i.e., compressive strength (CS), first crack tensile stress (TS), and first crack flexural stress (FS), using gene expression programming (GEP). Wide-ranging records were considered with twelve variables i.e., cement percentage by weight (C%), fine aggregate percentage by weight (Fagg%), fly-ash percentage by weight (FA%), Water-to-binder ratio (W/B), super-plasticizer percentage by weight (SP%), fiber amount percentage by weight (Fib%), length to diameter ratio (L/D), fiber tensile strength (FTS), fiber elastic modulus (FEM), environment temperature (ET), and curing time (CT). The performance of the models was deduced using correlation coefficient (R) and slope of regression line. The established models were also assessed using relative root mean square error (RRMSE), Mean absolute error (MAE), Root squared error (RSE), root mean square error (RMSE), objective function (OBF), performance index (PI) and Nash-Sutcliffe efficiency (NSE). The resulting mathematical GP-based equations are easy to understand and are consistent disclosing the originality of GEP model with R in the testing phase equals to 0.8623, 0.9269, and 0.8645 for CS, TS and FS respectively. The PI and OBF are both less than 0.2 and are in line with the literature, showing that the models are free from overfitting. Consequently, all proposed models have high generalization with less error measures. The sensitivity analysis showed that C%, Fagg%, and ET are the most significant variables for all three models developed with sensitiveness index higher than 10 %. The result of the research can assist researchers, practitioners, and designers to assess SHCC and will lead to sustainable, faster, and safer construction from environment-friendly waste management point of view.

Experimental Analysis of High-Strength Concrete Using Granite Aggregates

The present study investigates the effect of incorporating metakaolin and silica fumes in the production of high-strength concrete along with partial replacement of coarse granite aggregates in the high-strength concrete. The higher compressive strength, refined microstructure, and decreased permeability of high-strength concrete are some of the properties responsible for its trending use in the modern construction industry. The main purpose of this research is to evaluate the effect of the replacement of coarse granite aggregates with natural aggregates on the mechanical and durability properties of high-strength concrete. For understanding the effect of metakaolin, silica fume, and granite aggregates on the properties of high-strength concrete, various specimens such as cubes, cylinders, and cylindrical discs were cast and tested after 7, 14, and 28 days of curing. Various concrete mixes were prepared by adding silica fume at 5%, 7.5%, and 10% and metakaolin at 5%, 7.5%, 10%, 12.5%, and 15% in concrete production. Furthermore, High-strength concrete mixes were also prepared by replacing natural coarse aggregates with granite coarse aggregates by 25%, 50%, 75%, and 100% to study the effect of replacement percentage on the concrete properties. Test results indicated that the compressive strength and split tensile strength of the concrete mix increased with the increase in the replacement percentage of granite aggregates, with the highest strength seen at complete replacement with granite aggregate due to the enhanced compressive strength of such aggregates in comparison with the natural coarse aggregates. In various mixes cast using metakaolin and silica fume, the highest compressive strength was seen in a mix containing 10% metakaolin and 7.5% silica fume, and results of other mixes indicated that the use of silica fume and metakaolin are viable options for high-strength concrete production in our experimental study.

Treated recycled coarse aggregate concrete: A new mixture proportioning method based on packing densities

In this paper, recycled coarse and fine aggregate collected from concrete rubble are treated with acid to remove the adhered cement mortar on the aggregates. These treated recycled aggregates both in fine and coarse aggregates are used to prepare concrete with water-cement ratio of 0.55 based on newly developed mix design method using packing densities. In this study two different recycled coarse aggregate sizes of 10 mm (40 % by mass fraction) and 20 mm (60 % by mass fraction) are used for various replacement levels of natural aggregates. The ratios of aggregates mixture of CA20, CA10 and FA are 38.4:25.6:36.0 by mass. For various packing densities, the recycled aggregates content is evaluated. Quantities for recycled aggregate concrete mixes made with 100 % recycled fine aggregate (RFA) and various replacement percentages of recycled coarse aggregate (RCA) for 0.55 w/c ratio are arrived at. Workability of concrete made with 100 % RFA in terms of slump (mm) can be enhanced by adding 5 % GGBS by mass of cement. Compressive strengths of concrete made with 0 to 100 % replacement of treated recycled fine and coarse aggregate ranges from 27.21 to 19.05 MPa. But when cement or silica fume is added to the recycled aggregate concrete then the compressive strengths are comparable to that of concrete made with natural aggregates.

Comparison of Peat–Perlite-based and Peat–Biochar-based Substrates with Varying Rates of Calcium Silicate on Growth and Cannabinoid Production of Cannabis sativa ‘BaOx’

Growers have been searching for alternative horticultural growing media components because of their desire to use sustainable resources. Biochar is a carbon-based material that has been evaluated for use as an alternative aggregate in peat-based soilless substrates. Additionally, silicon (Si) has been examined as a beneficial element to promote plant growth and plant quality in a variety of crops. However, there has been limited research regarding the interaction of biochar as an aggregate and Si in soilless substrates. This study aimed to determine the impact of Si and biochar on plant growth and nutrient uptake for greenhouse-cultivated hemp (Cannabis sativa L.). Hemp plants were grown in one of 12 different substrate blends: with two rates of calcium silicate (CaSiO3), two aggregate types of biochar (medium or coarse) or perlite, and aggregate percentages of 85% peat + 15% aggregate and 70% peat + 30% aggregate. The cannabinoid concentration, plant height, diameter, or total plant biomass were similar across all substrate blends after 12 weeks of growth. Additionally, the use of CaSiO3 as a Si substrate amendment increased Si foliar concentrations, and the addition of biochar to peat-based mixes did not limit the Si availability for plant uptake. However, Si substrate amendments did not impact plant height, diameter, or total plant biomass. This suggests that the biochar tested during this study is suitable in peat-based substrates for C. sativa ‘BaOx’ production at rates up to 30% (by volume) in peat-based substrates with CaSiO3 amendments.

Development of Pervious Paver Block Using Sugarcane Bagasse Ash & RAP Aggregates

Abstract: This particular kind of concrete is distinguished by its interconnected pore structure and significant void content or porosity, which typically varies from 15 to 35% by volume. Pervious concrete may lower the danger of flooding, diminish stormwater runoff, reduce noise when in contact with automobile tires, and avoid glare and skidding during rainy seasons by allowing water to easily infiltrate through its pores and replenish the ground water table. Considering the condition of the neighboring roadways, a modest effort is undertaken to construct the least amount of porous paver concrete. For the planned Mix proportions, compression strength, void ratio, and infiltration tests were conducted. In the current study, 60mm thick pervious paver blocks for medium traffic with different RAP aggregate percentages and sugarcane bag ash are cast. This improves the compressive strength. RAP aggregates are a suitable material that may be utilized in place of natural and artificial aggregates in construction projects. The thesis shows how discarded sugarcane ash may be used again. Several experiments were conducted to evaluate the compressive strength, density test, porosity, and permeability of the planned paver block as well as its durability.

IMPACT OF DEICING SALT ON THE PERFORMANCE OF ASPHALT MIXTURES IN NORTHWEST CHINA: AN INVESTIGATION INTO MECHANICAL PROPERTIES AND INFLUENTIAL FACTORS

Currently, the primary form of high-grade highways is constituted by asphalt concrete pavement. Winter conditions often result in ice and snow accumulation on these pavements, precipitating severe traffic incidents. Statistically, around 15%-30% of such incidents are directly linked to icy and snowy conditions. Hence, when roads are laden with ice and snow, the most cost-effective and efficient countermeasure remains the dispersal of deicing salt onto the road surface. Particularly in China's northwestern region, which experiences low precipitation and consistent droughts, the deicing salts applied during winter aren't diluted or transported away by water flow. Consequently, the soil surrounding the roads retains a higher concentration of deicing salts than other regions, leading to a pronounced impact on the pavement's service life. This investigation aims to experimentally emulate the impact of this high-salt environment on the mechanical properties of asphalt mixtures, followed by an analysis of the crucial factors that influence the asphalt mixtures' durability. The current study employs measures such as high-temperature rut testing, Marshall water immersion testing, and freeze-thaw splitting testing to investigate the damage patterns of mechanical properties in asphalt mixtures under varying grading, diverse deicing salt solutions, and differing frequencies of dry-wet cycles. In addition, the study employs grey correlation entropy analysis to ascertain the interdependence among factors influencing the performance of asphalt mixtures. The findings reveal that after undergoing 0, 5, 10, 15, 20, 25, and 30 dry-wet cycles in solutions of 20% industrial salt (NaCl), 15% urea (CH4N2O), and 20% anhydrous ethanol (CH2CH3OH), both the high-temperature stability and water stability of asphalt mixtures with AC-13 and AC-16 gradings displayed varying levels of decline. Overall, an enhancement in the fine aggregate percentage in asphalt mixtures can augment the asphalt concrete's resistance to deicing salt erosion. As per the grey correlation entropy analysis, gradation variances exerted the most significant impact on diverse mechanical properties, followed by the type of deicing salt solution, with the least significant impact attributed to the frequency of dry-wet cycles. Thus, judicious selection of road materials and structural design can effectively counter the erosive action of deicing salts, thereby enhancing the service life of the road surface.