Lime Content Research Articles

An Exploration of Alkaline Degumming in the Printing and Dyeing Process of Silk Georgette

Alkali printing was one of the traditional techniques employed for printing on silk georgette in ancient China. This study investigates two degumming methods in alkaline printing processes, namely alkaline boiling and alkaline steaming, based on the principles of Tang Dynasty alkaline printing techniques. The effects of slaked lime concentration, steam temperature, and steam duration on the degumming rate of silk georgette are studied. Alkaline boiling is found to be rapid and effective, achieving a degumming rate of 27% at 80 °C in 30 min, whereas alkaline steaming requires a prolonged process with a maximum degumming rate of less than 20% before the water reaches its boiling point. Additionally, the differences in dyeing effects at various degumming rates, and the variations in pattern clarity and detail under alkaline steaming, were compared. Although both degumming methods can achieve the desired amount of degumming rate through process control, alkaline steaming allows for integration with methods like screen printing and rotary printing, offering better control over pattern freedom and detail. The combination of these two processes can further expand the artistic expression and application of traditional alkaline printing techniques in contemporary silk degumming printing.

Stress-Strain Behavior of Soft Soil Stabilized with Nickel Slag, Limestone, and Aluminum Hydroxide

Soil stabilization by combining several minerals is a form of material engineering aimed at increasing the bearing capacity of the soil to a higher level. The development of waste-based materials and the utilization of local potential are part of environmentally conscious construction. This study aims to analyses the mechanical behaviour of soil stabilized with several pozzolanic materials derived from nickel processing waste and limestone, which are local materials with very large deposits. ASTM standards were used in this study for both physical and mechanical testing. Unconfined compressive strength (UCS) tests were conducted to compare the mechanical behaviour of stabilized soil with that of natural soil. The test samples used were cylindrical with a diameter of 35 mm and a height of 70 mm. The binding materials consisted of nickel slag, aluminium hydroxide, and limestone, with the amount of each material based on the dry soil weight (γdry). The addition of lime in this study was varied at 2%, 4%, and 6%. The test results generally show that lime variations and curing time affect the increase in unconfined compressive strength (qu), with the highest value of 30.91 kg/cm² observed at 6% lime content after 28 days of curing.

Use of Nondestructive Impedance Spectroscopy for the Assessment of Clay–Lime Reaction Kinetics: Influence of Clay Mineralogy, Lime Content, and Curing Conditions

Use of Nondestructive Impedance Spectroscopy for the Assessment of Clay–Lime Reaction Kinetics: Influence of Clay Mineralogy, Lime Content, and Curing Conditions

A Robust Static Model of Basic Oxygen Furnace for Analyzing Emerging Steelmaking Scenarios

A robust static model, which incorporates emerging steelmaking scenarios in terms of solid charge mix with the given hot metal in basic oxygen furnace process, is developed. It employs mass and enthalpy balances to comprehend nonequilibrium conditions, considering four key empirical parameters: iron loss, post‐combustion ratio, heat loss, and undissolved lime content in slag, which are fine‐tuned using plant data through a multivariate approach, ensuring the reliability. The model is validated in a basic oxygen furnace (BOF) shop using data from over 4000 heats, achieving a strike rate of ≈77% for input lime prediction within ±1 ton and ≈80% for input oxygen prediction within ±600 Nm3. Model implementation in BOF shop provides valuable guidance to the operators, resulting in the reduction of average oxygen and lime consumption by 139 Nm3 and 652 kg heat−1, respectively. The model also enables the determination of the maximum scrap utilization of ≈16% for 0.8% silicon and ≈14% for 0.6% silicon in hot metal, respectively. The model aids in calculating the maximum tap temperature for varying hot metal silicon and iron ore addition. Overall, the model optimizes primary steelmaking, enhancing efficiency, reducing resource consumption, and offering insights into alternative iron sources like direct reduced iron.

Incorporation of undissolved lime from previous applications can ameliorate subsoil acidity promptly and improve crop performance on sandy soils of the semi-arid regions of Western Australia

Abstract Background and aims Repeated surface application of lime for managing subsoil acidity is slow and ineffective, resulting in an accumulation of undissolved lime (carbonate) in the topsoil. We investigated the impact of the incorporation of undissolved lime into the subsoil to improve acidity and crop performance. Methods The undissolved lime in 2-cm layers of topsoil (0–10 cm) from three long-term experiments in Western Australia was measured. Both limed and unlimed topsoil with the acidic subsoil of the same profile was incubated at eight incorporation rates for six weeks, followed by growing barley and wheat in the incubated soil for two weeks to assess the impact on soil acidity and crop root architecture, respectively. Furthermore, a three-year-long field experiment was conducted following strategic tillage in limed and control plots to assess the impact on soil acidity and performance of wheat, canola and barley. Results A significant amount of undissolved lime was concentrated in the topsoil, amounting to 1.7, 1.8 and 1.3 t/ha for the limed plots at Wongan Hills, Northam and Merredin, respectively. Incubation of 5–25% topsoil after incorporation with the acidic subsoil was enough to ameliorate subsoil acidity and to improve root length density by up to 13-fold depending on undissolved lime content in topsoils and soil type. In the field experiment, the incorporation of undissolved lime also significantly improved subsoil acidity and canola performance. Conclusion We concluded that the incorporation of topsoil containing sufficient undissolved lime with acidic subsoil may offer a quick amelioration of subsoil acidity.

Effect of Lime Concentration on Physical Properties on the Raw & Developed Pumpkin Petha and Cost Analysis of Prepared Petha

Effect of Lime Concentration on Physical Properties on the Raw & Developed Pumpkin Petha and Cost Analysis of Prepared Petha

Fracture characteristics of SMA mixtures with hydrated lime through the semi-circular bending approach

Stone Mastic Asphalt (SMA) is a composite mixture made up of high-quality crushed stone, fine aggregates, an asphalt binder, and a significant percentage of mineral filler in contrast to conventional mixtures. Renowned for its durability and rolling resistance, it is predominantly employed as a surface “wearing” course on main roads subjected to heavy traffic, but it can also be used as a binder course under specific project requirements. In this study, we investigated the effect of hydrated lime as a partial replacement of limestone filler at various concentrations on the mechanical and cracking resistance characteristics of 10-mm SMA mixtures. The semi-circular bending (SCB) test, which is pivotal for understanding the cracking mechanism was used to assess the mixtures performance-related response to this distress type. The mixture cores were produced with granite aggregates, limestone filler as natural filler, hydrated lime as natural filler replacement, and a 30/45 penetration asphalt type. Mixtures containing 1.1 %, 2.2 %, and 3.4 % of hydrated lime by weight of aggregates were evaluated, in addition to a control mixture without hydrated lime. The factors considered for comparing the mixtures included: load and deformation curves, stiffness, fracture toughness, fracture energy, and flexibility index of the mixtures. The experimental program also comprised a set of various test temperatures (0°C, 10°C, and 20°C) to better understand the cracking mechanism. Experimental results indicated a significant performance-dependency on the HL concentration and the test temperature. Precisely, it was found that the mixture with the highest hydrated lime content (3.4 %) exhibited the best cracking performance at 0°C and 20°C, making it a suitable filler replacement concentration. However, at 10°C, the mixture containing 2.2 % hydrated lime showed the most consistent performance overall, suggesting and important improvement in asphalt mixtures’ cracking resistance. Overall, these findings obtained from the SCB test approach substantiate the potential benefit of hydrated lime filler replacement in optimizing the cracking performance and durability of SMA mixtures under varying temperature conditions and loading regimes.

Evaluating the Role of Mortar Composition on the Cyclic Behavior of Unreinforced Masonry Shear Walls.

The mechanical behavior of unreinforced masonry (URM) shear walls under in-plane cyclic loading is crucial for assessing their seismic performance. Although masonry structures have been extensively studied, the specific influence of varying lime content in cement-lime mortars on the cyclic behavior of URM walls has not been adequately explored. This study addresses this gap by experimentally evaluating the effects of three mortar mixes with increasing lime content, 1:0:5, 1:1:6, and 1:2:9 (cement:lime:sand, by volume), on the cyclic performance of brick URM walls. Nine single-leaf wall specimens 900 mm × 900 mm were constructed and subjected to combined vertical compression and horizontal cyclic loading. Key parameters such as drift capacity, stiffness degradation, and energy dissipation were measured. The results indicated that the inclusion of lime leads to a moderate improvement in drift capacity and ductility of the walls, with the 1:1:6 mix showing the highest lateral capacity (0.55 MPa), drift at cracking (0.08%), and drift at peak capacity (0.31%). Stiffness degradation and energy dissipation were found to be comparable across all mortar types. These findings suggest that partial substitution of cement with lime can enhance certain aspects of masonry performance. Further research is recommended to optimize mortar compositions for unreinforced masonry applications.

Determinación de los factores que afectan el color y el contenido de azúcar de la panela de caña de azúcar (Saccharum officinarum L.)

The objective of this study was to determine the factors that affect the color and reducing sugar content of sugar cane (Saccharum officinarum L.), fundamental factors in the quality and marketing of product that must be evaluated and that will allow the improvement of the artisanal production of sugar cane panela. For this purpose, the MY5514 variety harvested at optimum maturity time was used and a 24 factorial design was applied to evaluate the incidence of the factors: ºBrix, purity (%), lime concentration (g.L-1) and baking temperature (ºC), on the response variables: "color" and "reducing sugar content (%)", under a completely randomized design with three replications. It was found that the significant factors for the response variable "color" for the three coordinates evaluated were: lime concentration (g.L-1), cooking temperature (ºC) and purity content (%) for the L* coordinate; ºBrix for the a* coordinate and purity content (%) for the b* coordinate. With respect to the response variable "reducing sugars (%)", the factors that significantly affected were cooking temperature (ºC) and purity content (%). It is recommended to use any of the combinations of these two factors, except the combination of 110 ºC and 95% purity, because generates a final product with commercial characteristics not desired by the consumer. Key words: sugar cane sugar, controllable factors, reducing sugars, ºBrix, purity (%), processing.

Characterization and Making Techniques of Calcareous Construction Materials for Phaya Thon Zu Temple in Bagan Historical Area, Myanmar.

The calcareous materials used in constructing the Phaya Thon Zu temple at the Bagan historical sites in Myanmar are mortars, plasters, and stuccos. Among them, the mortars and plasters are a mixture of original and new materials used for recent conservation treatments. In this study, the making techniques were examined through analysis of calcareous materials by production period. All calcareous materials have a mineral composition similar to soil, except calcite. Stuccos have the most refined aggregates, homogeneous particle size, and the highest lime and organic contents. They were designed to improve ease of carving and weathering resistance, considering the unique characteristics of the stuccos. Because all calcareous materials were mixed with soil, the origin of the clay materials was analyzed. It was concluded that the mortars were produced by mixing clay and sandy soil, and the original mortars showed characteristics similar to soil. It is highly possible that sandy soil from around the Htillominlo temple was used to produce new plasters, and it is estimated that a mixture of clay soil was used for the original plasters and stuccos. A clear provenance interpretation of the original and raw materials used for each construction and the mixing ratio of clay materials need to be discussed through experiments, along with the estimated provenance area of the raw calcareous materials.

Experimental analysis of mechanical properties of dredged sludge solidified by carbonized under the synergistic action of magnesium oxychloride cement and lime

The environmentally friendly magnesium oxychloride cement (denoted as MOC thereinafter) shows promising application prospects. Meanwhile, more emphasis is being paid to the environmental issues created by CO2 emissions. In this paper, carbonation-composite solidification technology is adopted to introduce MOC-lime cementitious material into sludge solidification. The effects of initial water content (H2O/MgCl2 molar ratio), lime content, MgO/MgCl2 molar ratio, and carbonation time on the mechanical properties and micro-mechanisms of sludge solidification were investigated using unconfined compressive strength (UCS), pH value, carbonation depth, mass loss rate, scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests. The results show that the UCS of sludge solidification decreases with an increase in H2O/MgCl2 molar ratio, and increases first and then decreases with an increase in lime content, reaching a maximum value at H2O/MgCl2 molar ratio of 24.3 and lime content of 4 %. Notably, carbonation significantly improves the UCS of the samples, and with an increase in carbonation time, the mass loss rate and carbonation depth increase, while the pH value decreases. Additionally, uncarbonated samples show an increase in compressive strength with an increase in MgO/MgCl2 molar ratio, as the hydration products gradually transform from amorphous gel to crystalline phases 3, phases 5, and brucite (Mg(OH)2). Finally, XRD and SEM results indicate that the underlying mechanism for the significant improvement in strength and microstructure of the samples after carbonation is the formation of a block-like crystalline network with good binding ability, consisting of chlorartinite, nesquehonite, calcium carbonate, and C-S-H gel. This study promotes the use of MOC-based gel materials as a green stabilizer for sludge solidification, and the carbonation technique employed can improve the mechanical properties of solidified soil and significantly reduce the curing time.

The influence of cement bypass dust composition on the properties of slag-based mortars

Research on sustainable alternatives to Ordinary Portland Cement aims to reduce global CO2 emissions from cement production. Utilizing byproducts or waste materials to create sustainable binders is a promising approach. Cement bypass dust is being investigated as a potential activator of pozzolanic materials, however there is large variability in the composition of this dust and research is necessary to understand the differences for the potential application of the waste material. The objective of this work was to compare two bypass dusts where ternary and binary mortars of bypass dust (50 %, 30 %, 10 %, 0 % and by weight), cement (100 %, 80 %, 40 % and by weight), and blast furnace slag (50 %, 30 %, 10 % and 0 % by weight), were produced. Mortars were all ambient cured and a water to binder ratio of 0.6 was maintained for all mixes. The results showed that one bypass dust had a much higher free lime and chloride content, whereas the other had more calcite and sulphates. Compressive strengths of the 1:1 slag and sulphate rich bypass dust were of 18.6 MPa at 90 days, and lime rich bypass dust achieved 15.1 MPa. X-ray diffraction and thermogravimetric analysis revealed that sulphate rich bypass dust formed more ettringite, enhancing strength, while lime rich bypass dust formed more portlandite due to its lime content. Chemical shrinkage results showed volumetric expansion at early ages for both bypass dusts with lime rich bypass dust swelling up to 0.057 ml/g and sulphate rich bypass dust up to 0.015 ml/. Despite this, both bypass dust binders exhibited higher shrinkage strains over a 150-day period compared to cement, where sulphate rich and lime rich bypass dust had strain percentages of 0.225 % and 0.228 %, respectively. This work found the main differences between the composition of two bypass dusts, and it was found that these materials can be reused to fabricate cementless binders.

Eco-friendly solid waste-based cementitious material containing a large amount of phosphogypsum: Performance optimization, micro-mechanisms, and environmental properties

Reusing phosphogypsum (PG) waste to manufacture eco-cementitious materials is sustainable. However, PG faces the challenge of high stacking volume and low utilization rate, and the low-content PG in eco-cementitious materials currently limits its large-scale potential application. This study provides a solution to use high-content PG to fabricate eco-friendly solid waste-based cementitious material (PBC), associated with ground granulated blast furnace slag (GGBS), fly ash (FA), and hydrated lime. Respond surface methodology (RSM) was undertaken to optimize and discuss the influence of independent design factors of GGBS, FA, and hydrated lime content on the unconfined compressive strength (UCS). Besides, the micro-mechanisms and environmental properties of PBC were also investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and the leachate test. The results indicated that the optimal raw material contents were (by mass): 50.57% PG, 28% GGBS, 20% FA, and 1.43% hydrated lime. The UCS of the optimal PBC mixture is 23.57 MPa at 28 days, which was confirmed via experimental verification (24.65 MPa). Hence, the RSM is an effective method for optimizing PBC's UCS. The micro-mechanisms analysis shows that the ettringite is the primary hydration product within the reaction system of PBC, which is attributed to the substantial amount of PG. The leachate test results indicate that the fluoride ion concentration of the leaching solution of PBC remains below the PG, and the pH value falls within the range of 6–9. The leaching test results meet the Chinese environmental standard of GB 8978-1996. The cost and CO2 emission of the optimal PBC mixture could achieve a reduction of 71.25% and 99.98%, respectively, compared to Ordinary Portland cement (OPC). The findings of this study could serve as a theoretical foundation for the practical implementation of large-scale and efficient utilization of PG waste. The developed eco-friendly PBC has excellent potential to partially substitute conventional OPC binders and reduce engineering project costs.

Experimental study on improving the performance of imitation earthen site soil in carbon dioxide environment

This study aims to explore the performance of lime-treated soil for repairing the lime soil of the earthen city wall of Kaifeng and to standardize the construction technology of lime-treated soil. The research comprehensively considered factors such as carbonation time, lime particle size, aging conditions, and lime content, and conducted various tests and analyses including triaxial mechanical properties, surface crack analysis, particle size distribution, pH measurement, composition analysis, and electron microscopy on different samples. The results indicate that the significant effect of high-concentration CO2 carbonation enhances the chemical reactions of lime soil, and an appropriate carbonation process can strengthen the bonding and density between soil particles. Under the maintenance condition of 5 % CO2, with increasing carbonation time, the crack ratio, average crack length, and average crack width of the samples decreased. Cohesion and internal friction angle of the samples exhibited an initial increase followed by a decrease, while shear strength of the samples increased by 22.93 %–75.09 %. The lime particle size has a critical impact on the formation of cracks in lime soil. With increasing lime particle size, the crack ratio, average crack length, and average crack width of the samples increased. Cohesion and internal friction angle of the samples gradually increased with increasing lime content. The increase in crack ratio, average crack length, and average crack width during natural curing of lime-treated soil samples was proportional to the lime content. Appropriate carbonation time, smaller lime particle size, and curing conditions with 5 % CO2 contribute to improving the particle size distribution of lime-treated soil samples, reducing surface cracks, and enhancing performance. However, prolonged carbonation may lead to larger lime particle size, resulting in rough and loose particles, disorganized arrangement of CaCO3 crystals, and the inability to form a cross-linked network skeleton, causing a reduction in shear strength of the samples. These research findings provide important theoretical basis and construction technology guidance for the application of lime-treated soil combined with CO2 carbonation in repairing earthen city walls.

Stabilization of Krobokan Clay Soil with California Bearing Ratio (CBR) for Highway Pavement

In this research, clay soil will be stabilized in the Kerobokan Badung area by mixing the soil with various levels of lime. The problem to be solved is how much the CBR value of soil mixed with lime will increase and what is the most economical lime content associated with the minimum CBR requirements for the base soil layer. The aim is to determine the increase in CBR value from a mixture of clay with lime and to determine the most economical lime content associated with the minimum CBR requirements for the base layer of highway pavement structures. The research results show that adding lime to clay soil can increase its bearing capacity. For the standard compaction method, the CBR of the base soil which was initially 3.32% increased to 12.14, 21.86, and 26.24% for lime addition of 2.50, 5.00, and 10.00% respectively. For the modified compaction method, the CBR of the base soil which was initially 5.74% increased to 13.42, 25.69, and 38.15% for lime addition of 2.50, 5.00, and 10.00% respectively. To produce a base soil CBR of 6%, the modified compaction method requires less lime content than the standard method. The lime content required is 0.22% for modified compaction and 0.79% for standard compaction.

Sustainable ground improvement of soft clay using eggshell lime and rice husk ash

Stabilization of clay using lime or cement is conventionally accepted practice. Although it is effective, they impose several implications on the environment. Hence, it is high time that an alternate sustainable binder needs to be investigated. Eggshell, a waste from food industry, is an alternate source for calcite and can be considered to produce eggshell lime (EL). Also, rice husk ash (RHA), an agricultural waste product, is a silica rich source which is a pozzolanic material. In the current study, the efficiency of both the materials in stabilizing the soft soil is investigated and the results suggests that the plasticity and the strength characteristics of soft clay can be significantly improved by the addition of EL. After adding optimum concentration of 3 % EL, the liquid limit decreased from 74 % to 53 %, plastic limit increased from 27 % to 46 % and shrinkage limit increased from 8 % to 44 %. On increasing the EL content, the swelling got reduced from 88 % of virgin clay to 17 % in case of 3 % EL and finally to zero with 5 % of EL. Also, the addition of combination of EL and RHA to the soft clay has improved the strength characteristics significantly. As the curing days increased, slight variation was only seen in the plasticity characteristics which may be due to rapidity of cation exchange. But strength characteristics increased suggesting the occurrence of pozzolanic reactions and formation of gel. The 28th day strength of the clay treated with 3 % EL increased to as high as 757 kPa. The strength characteristics showed that as we increase the percentages of EL and RHA combination, the strength would increase tremendously much better than the treatment with eggshell lime alone. This is because of the supply of CaO and SiO2 sources. For 5 % of EL and 15 % of RHA, the 1 day curing strength was near to 500 kPa. With less concentration of eggshell lime and RHA, the treated soil was appearing to be more porous in SEM while when the binder concentration was increased, the pores were filled and presence of C-S-H gel was also detected. XRD test results also showed the presence of C-S-H gel.

Micronized PET as a green additive for lime stabilization of swelling soil

The use of Polyethylene Terephthalate (PET) as an additive in the stabilization of swelling soils is a sustainable option considering the increasing environmental pollution caused by improper disposal of plastic waste. Given the limited capacity of recycling programs, incorporating these materials in construction can be a viable solution. In the conducted study, compacted mixtures of soil-lime-PET were prepared at different dry unit weights (14, 15 and 16 kN/m³). Micronized PET was used with percentages of 5% and 10%, while hydrated lime was added at 0%, 2%, 4%, and 6%, both by dry mass. These mixtures were subjected to one-dimensional swelling tests. The results showed that the PET content, lime content, and porosity are significant factors influencing the behavior of compacted mixtures. The index porosity/volumetric lime content adjusted by an exponent (ƞ/(Liv)-0,26) can link the one-dimensional swelling behavior. The combination of both materials creates a sustainable solution for controlling soil swelling.

Basic oxygen furnace (BOF) slag as an additive in sodium carbonate-activated slag cements

Basic oxygen furnace slag (BOFS) is a high-volume waste resulting from the production of steel from pig iron. Due to its high free lime content, BOFS is difficult to recycle and/or include into conventional cement systems. Alkali-activation technology offers a pathway to transform industrial wastes such as BOFS into low-carbon cements. Alternative precursors for cement systems are needed as the reliance on commonly used materials like ground granulated blast furnace slag (GGBFS) is becoming unsustainable due to decreasing availability. This study investigates alkali-activated cements incorporating 20 and 30 wt.% of naturally weathered BOFS as a replacement for GGBFS, in both sodium silicate- and sodium carbonate-activated systems. A fraction of BOFS subject to mechanical activation is compared against the untreated BOFS in the 20 wt.% systems. It is observed that in naturally weathered BOFS, a significant portion of the free-lime is found to convert to portlandite, which accelerates alkali-activation kinetics. In sodium silicate-activated systems, the high pH of the activator results in incomplete reaction of the portlandite present in BOFS. The sodium carbonate-activated system shows near complete conversion of portlandite, causing an acceleration in the kinetics of reaction, setting, and hardening. These findings confirm the viability of sodium carbonate activated GGBFS-based systems with only a minor loss in strength properties. BOFS can be utilised as a valuable cement additive for the production of sustainable alkali-activated cements utilising sodium carbonate as a less carbon-intensive activator solution than the more commonly used sodium silicate. Mechanical activation of BOFS offers further optimisation potential for alkali-activation.

Analysis of Lime Content (CaCO3) in Clean Water Sources in Tampo Village, Napabalano District, Muna Regency

Salah satu indikator penting untuk penilaian air layak konsumsi bagi masyarakat adalah kandungan kapur atau biasa disebut sebagai kesadahan air. Menurut World Healt Organization (WHO), bahwa air yang mengandung zat kapur tinggi dapat menimbulkan dampak terhadap kesehatan seperti penyumbatan pembuluh darah jantung (cardiovascular desease), batu ginjal (urolithiasi) yang dapat menyebabkan kencing batu serta masalah kesehatan lainnya, masalah ekonomi seperti penggunaan detergen serta dalam bidang industri seperti adanya kerak pada mesin. Kandungan mineral yang terkandung dalam air sangat dipengaruhi oleh lingkungan sekitarnya. Kelurahan Tampo, Kecamatan Napabalano secara geologis tersusun oleh batugamping dan merupakan daerah karst yang berkembang dengan baik. Keberadaan daerah karst dan kondisi tipologi batuan, menjadikan wilayah Kelurahan Tampo sebagai daerah berkapur dan ancaman sumber air tanah memiliki kadar kapur yang cukup tinggi. Oleh Karena itu, perlu Identifikasi dan Pengukuran Kandungan Kapur (CaCO3) Sumber Air Bersih di Kelurahan Tampo, Kecamatan Napabalano, Kabupaten Muna. Penelitian ini dilaksanakan dengan Pengambilan sampel secara acak pada beberapa sumur gali masyarakat yang digunakan sebagai air bersih. Analisis sampel air yakni kadar kapur atau tingkatan kesadahan air dilakukan seacara kualitatif dan kuantitatif. Secara kulitatif menggunakan metode elektrokoagulasi sedangkan secara kualitatif menggunakan metode Atomic Absorption Spectrophotometry (AAS) dan Titrasi EDTA di Laboratorium Forensik FMIPA UHO. Berdasarkan hasil analisis laboratorim pada 12 sampel air, terdapat 11 sampel memiliki tingkat kesadahan tinggi dan 1 sampel memiliki tingkat kesadahan rendah. Jadi, secara keseleuruhan sampel air yang ada di Kelurahan Tampo memiliki tingkat kesadahan yang cukup tinggi

Projection-Pursuit Regression-Based Optimization of Frost Resistance and Mechanical Performance in Alkali-Activated Slag Cement Pavements

In recent years, applying slag micro-powder as a substitute for cement in preparing alkali-activated slag cement stabilized sand (AASCSS) mixtures has become increasingly widespread. In the severe cold regions of Xinjiang, multi-objective optimization of the mechanical and frost resistance properties of AASCSS is particularly crucial. This paper adopts slag micro-powder to replace Portland cement, together with lime and desulfurization gypsum as activators, to explore the effects of activator type and dosage on the mechanical and frost-resistance properties of AASCSS. A prediction model for the mechanical and frost-resistance properties of AASCSS based on projection-pursuit regression (PPR) was proposed and established. Using the developed PPR model, contour plots of the comprehensive performance were calculated, simplifying the multi-objective problem into two single-objective problems focusing on mechanical and frost resistance properties for analysis. This method avoids subjective weighting and hypothesis-based modeling. By analyzing the contour plots of comprehensive performance, the optimal performance indices for mechanical and frost–thaw properties and the corresponding types and dosages of activators can be directly determined. When the required 7-day unconfined compressive strength in road engineering is 5.6 MPa, the optimal value of the freeze–thaw performance index (BDR) is 94.08%. At this point, the corresponding lime content is 2.1%, and the desulfurization gypsum content is 3.3%. The research results provide a reference for applying slag to road-based materials.