Addition Of Lime Research Articles

The Effect of Adding Gypsum and Lime on Lightweight Interlock Bricks with Merapi Sand as Fine Agregat

Lightweight materials will reduce the earthquake forces received by the structure. Interlock lightweight brick is a new innovation in the building industry that functions as wall material. Utilization of local materials in Central Java-Yogyakarta, namely Merapi sand, needs to be developed to maximize its potential utilization as an aggregate of lightweight interlock brick. In many research, lime and gypsum as additives have been shown to improve the quality of concrete. This study aims to determine the characteristics of the addition of gypsum and lime as an added material for lightweight interlock bricks with fine aggregate of Merapi sand. The standard of test object and the test refers to SNI 8640-2018. The results showed that in dry weight all the mixed variations were categorized in the 900 kg/m3 and 1100 kg/m3 classes. All variations also complied with water absorption requirements in SNI 8640-2018, but only variations of 2.5% gypsum addition and 5% lime addition meet the compressive strength requirements. This mixture has the highest average of compressive strength value compared to other mixtures. Based on SNI 8640-2018 lightweight interlock bricks with the addition of 2.5% gypsum and 5% lime can be used as wall bricks.

Relative role of soil nutrients vs. carbon availability on soil carbon mineralization in grassland receiving long-term N addition

High nitrogen (N) input often induces soil carbon (C) limitation, eutrophication of macronutrients, deficiency of base cations, and accumulation of toxic micronutrients. These changes are perceived to be critical factors in regulating soil C mineralization. Previous studies primarily focused on the individual effects of C, macronutrients, exchangeable base cations, and micronutrients on soil C mineralization. However, the relative importance of those factors in regulating soil C mineralization, especially in N-enriched ecosystems, remains unclear. To disentangle the relative contributions of aforementioned factors, lime and/or glucose were added to soils that were collected from a field experiment with historical N addition (6 years) at seven rates (0–50 g N m−2 year−1) in a grassland ecosystem. Lime and glucose were added to improve the soil C and key nutrient conditions. The responses of soil C mineralization rate to changes in soil C and macronutrients (N and P), exchangeable base cations (K+, Na+ and Mg2+), and micronutrients (Fe2+, Mn2+, Cu2+ and Zn2+) were examined. We found that lime addition decreased soil micronutrients, while glucose addition improved the soil available P and exchangeable base cations, especially at high historical N addition rates. The soil C mineralization was weakly associated with changes in soil nutrients, including the availability of N, P, exchangeable base cations, and micronutrients, which were conventionally and previously considered as the vital drivers of soil C mineralization. However, soil C mineralization strongly increased with glucose-induced enhancement of C availability and the subsequent enhancement of microbial biomass under increasing N addition rates. Based on the Structural Equation Model, the standardized total effects of C, macronutrients (N and P), base cations and micronutrients on soil C mineralization were 0.86, − 0.29, 0.15 and − 0.08, respectively. Findings from this study demonstrated that the N-induced significant changes in soil nutrients (e.g., eutrophication of N and P, base cations deficiency and accumulation of toxic macronutrients) mediated soil C mineralization, with C availability being the most critical driver for C mineralization in N-enriched soil. This study provides insight into the mechanistic understanding of the relationship between N input and terrestrial C cycling.

Biogas Production from Tofu Processing Waste and Rice Straw with the Addition of Beef Bone Lime

The waste processing of tofu and rice straw can be used as the basic material for making biogas. The acidic pH of the waste will cause a non-optimal biogas production. This research was conducted using NaOH and the variations of beef bone lime 3 replications. The purpose of this study was to obtain the value of volume, pressure, biogas production rate and flame quality. The result showed the best quality of flame with a blue color (for 64.48 seconds) and 962 ml/day of biogas production rate was obtained by adding 3% of beef bone. The highest volume was obtained by adding 3% of beef bone lime (2210.33 ml) and the highest pressure was obtained by adding 2% and 3% of beef bone lime (1.0159 bar).

Material Cost and Benefit Analysis for Dust Injection Technology in EAF Steelmaking Process and EAF Dust Treatment with CaO Addition

In the electric arc furnace (EAF) steelmaking process, electric arc furnace dust (EAFD) is inevitably generated. The dust injection method is known as one of the effective technologies to reduce the total amount of EAFD generation. In this technology, Zn in the injected dust is enriched in the secondary dust, and Fe is transferred to the slag. In this work, the effect of dust injection technology on the recovered/lost amounts of Zn and Fe is quantitatively evaluated based on the mass balance calculation. Furthermore, in terms of dust and slag treatment costs, the potential of new EAFD treatment technology (the lime addition method) which enables simultaneous Zn and Fe recovery is discussed. By introducing the lime addition method, Zn and Fe can be recovered as resources, and the total income from these sales outweighs the cost of the chemicals used for recovery. This indicates that the treatment costs paid by EAF companies can be significantly low. The dust injection technology reduces the total quantity of dust shipped, but increases the total amount of slag and Fe loss. Therefore, it is necessary to determine the appropriate value of the amount of dust injection by balancing the waste treatment cost and the amount of metal resource recovery.

Comparative Study on the Impact of Sand and Lime on the Physical and Mechanical Characteristics of Unfired and Fired Earth Bricks

Earth bricks represent one of the most important and widely used building materials in current era, due to its unique physical and mechanical properties compared to other materials. Earth bricks are available in two main types: raw earth bricks and fired bricks. The physical and mechanical properties differ for each type, which affects their performance in various applications and their long-term durability. Several studies have been conducted to improve the properties of raw and fired bricks and address their weaknesses. In this research, we aim to investigate the effects of adding dune sand and lime on the physical and mechanical properties of raw earth and fired bricks, and compare the results. Sand was added by 25%, while lime was added by 0, 6, 8, 10, and 12% of the soil matrix weight. Initially, we determined the properties of the raw materials used. After creating the samples, they underwent tests for bulk density, longitudinal shrinkage, compressive strength, and flexural strength. The study revealed the positive impact of adding sand on the physical and mechanical properties of raw and fired bricks. It contributed to reducing the bulk density and longitudinal shrinkage of the samples, while increasing their compressive and flexural strength to varying extents. The results also showed the positive effect of lime on the physical and mechanical properties of raw bricks, as long as it was added at a ratio not exceeding 10%. However, the addition of lime to fired bricks affected the physical properties positively but it has a negative effect on the mechanical properties.

Carbon and Nitrogen Mineralization Kinetics in Soil Under Differential Nutrient Management Regimes in Inceptisols of Coastal India

ABSTRACT In intensive cropping systems, nutrient, and residue management techniques have a tendency to change the soil’s carbon (C) and nitrogen (N) cycle and, consequently, its potential for sequestration and loss. To understand the carbon and nitrogen mineralization kinetics, laboratory incubation studies were conducted with soils at variable depths from a long-term nutrient management experiment on cereal-vegetable-pulse cropping system. The experiment was laid out completely randomized design with 10 treatments replicated thrice. Long-term integrated application of inorganics with organics, biofertilizers, and amendment along with crop residues showed higher carbon and nitrogen mineralization potential and lower potential was observed in soils where crops were raised without application of any nutrient inputs (control) and uncultivated fallow. It was calculated that the potential for higher levels of carbon and nitrogen mineralization existed in the surface (0–15 cm) and subsurface (15–30 cm) layers, respectively, and was negligible in the deeper layer (30–45 cm). The mineralization rate was initially faster up to 42 days of incubation, indicating proper utilization of readily decomposable soil organic matter in the labile pools and thereafter found to slow down. Addition of lime along with the integrated use of organics and inorganics has found to raise the pH to a level that provides a suitable soil environment which affects the carbon and nitrogen mineralization kinetics resulting in buildup of total organic carbon and total nitrogen in the soils. The first-order kinetic model was the best fit in explaining the kinetic parameters of C and N mineralization. Soils under integrated nutrient management (INM) with farmyard manure (FYM) along with biofertilizers, amendment, and inorganic nutrients exhibited better carbon dynamics higher C mineralization (Cmin), potentially mineralizable C (C0), rate of C mineralization (dCmin/dt), and C mineralization quotient (qM), whereas soils applied with similar combinations with vermicompost was found effective for better nitrogen dynamics in terms of enhanced N mineralization (Nmin), potentially mineralizable N (N0), rate of N mineralization (dNmin/dt) and active N fraction over control and fallow soils. Integrated application of inorganic and organic inputs with crop residues over the years has shown beneficial impacts on soil carbon and nitrogen mineralization processes and their kinetics.

Effect of orange waste pretreatment on the fluid dynamics of spouted beds with mechanical agitation

The spouted bed has a vigorous cyclic movement of the solids and high rates of heat and mass transfer, allowing for effective contact between the different phases. However, the spouted bed may exhibit instabilities for inherently cohesive solids due to unwanted agglomeration, preferential channels, particle segregation and high energy consumption. In this context, the present work analyzed the effect of a preliminary treatment of the orange waste, through the addition of lime and mechanical pressing, on the fluid dynamics in two spouted bed configurations of same dimensions, one conventional (CSB) and the other one modified with mechanical agitation (modified mechanically spouted bed, MMSB). The preliminary treatment of the biomass allowed reducing the moisture content by 31.7%, thereby improving the movement of solids in the CSB as when the in natura (raw) biomass was loaded, as the latter underwent agglomeration until it no longer circulated. Persistent instability issues in the CBS were overcome through mechanical stirrers, which made the bed uniform by improving the movement of solids in the annular region. Furthermore, mechanical agitation allowed increasing the maximum static bed height from 21.1 to 27.0 cm, as well decreasing the air flow by up to 91.74%, since the air stream is only that required for bed expansion.

Effect of lime and calcium magnesium phosphate on gaseous emissions, maturity, and bacterial dynamics during food waste composting

This study estimated the effects of 0.5–1.5% lime and 10% calcium magnesium phosphate fertilizer (CaMgP) addition (dry mass) on maturity, gaseous emissions, and bacterial dynamics during food waste composting. The 1.0% and 1.5% lime amendments accelerated the proliferation of Thermobifida and Saccharomonospora for a higher germination index. The growth of methanogens (e.g., Tepidimicrobium and Caldicoprobacter) and Bacillus was restrained by additives to reduce the methane (CH4) and ammonia (NH3) emissions, respectively. Lime and CaMgP also limited denitrification by increasing pH, resulting in lower nitrous oxide (N2O) emissions. In detail, the highest decrease in N2O (59.35%) and hydrogen sulfide (H2S, 22.21%) emissions were observed in the 10% CaMgP group. The 0.5–1.0% lime treatments exhibited the highest alleviation in CH4 (80.77%) and NH3 (39.85%) emissions. Nevertheless, 1.5% lime addition promoted bacterial abundance in S cycle for a higher H2S emission.

Effects of Iron, Lime, and Porous Ceramic Powder Additives on Methane Production from Brewer's Spent Grain in the Anaerobic Digestion Process.

The process of anaerobic digestion used for methane production can be enhanced by dosing various additive materials. The effects of these materials are dependent on various factors, including the processed substrate, process conditions, and the type and amount of the additive material. As part of the study, three different materials-iron powder, lime, and milled porous ceramic-were added to the 30-day anaerobic digestion of the brewer's spent grain to improve its performance. Different doses ranging from 0.2 to 2.3 gTS × L-1 were tested, and methane production kinetics were determined using the first-order model. The results showed that the methane yield ranged from 281.4 ± 8.0 to 326.1 ± 9.3 mL × gVS-1, while substrate biodegradation ranged from 56.0 ± 1.6 to 68.1 ± 0.7%. The addition of lime reduced the methane yield at almost all doses by -6.7% to -3.3%, while the addition of iron powder increased the methane yield from 0.8% to 9.8%. The addition of ceramic powder resulted in a methane yield change ranging from -2.6% to 4.6%. These findings suggest that the use of additive materials should be approached with caution, as even slight changes in the amount used can impact methane production.

The Effect of Wetfix and Nanohydrated Lime Additives on Bitumen Aging and the Cohesion and Adhesion Failure Mechanisms of Hot Asphalt Mixtures

Aging due to sunlight and the passage of time is an effective element in the occurrence of moisture damage in hot asphalt mixtures. Still, the effects of this parameter are scarcely considered in the experiments examining the moisture damage potential. Accordingly, this study investigated the effect of aging on the performance of hot asphalt mixtures and examined the improvement of moisture damage performance by using antistripping additives via mechanism and functional tests. Two types of aggregates (limestone and granite) with different degrees of moisture sensitivity, two types of bitumen (PG64-16 and PG58-22) with different performances, and two additives (Wetfix liquid additive and nanohydrated lime) as bitumen modifiers were used. Bitumen samples and asphalt mixtures were subjected to short- and long-term aging. The pull-off test was performed to explore the aging effect on different failure mechanisms (cohesion and adhesion), and the indirect tensile stiffness modulus (ITSM) test was conducted to study the asphalt mixture’s performance against moisture damage. The results specify that aging, in terms of hot asphalt mixture hardening in dry and wet conditions, decreased the MSR (resilient modulus wet to resilient modulus dry ratio), and this decline was greater in long-term aging. The pull-off test results exhibited that aging, especially in the long term, decreased the asphalt mixture’s adhesive strength in dry and wet conditions; this decline in adhesion was greater in the wet than in the dry state, and this difference decreased the wet-to-dry adhesion strength ratio (the pull-off ratio). The additives relatively improved the yield modulus of the asphalt mixture, but their effect was greater in the wet state. A comparison of the pull-off test results in cohesion and adhesion failure demonstrated that Wetfix was more effective in improving bitumen–aggregate adhesion, whereas nanohydrated lime was more effective in enhancing bitumen adhesion. The resilient modulus (Mr) ratio in wet-to-dry conditions indicated that nanohydrated lime had better effects on the overall performance of the aged asphalt mixture against moisture damage. To investigate the effect of additives on the performance of asphalt mixtures, a t-test was performed in all modes of control, short-term aging, and long-term aging. The findings showed the effect of Wetfix and nanohydrated lime on increasing the modulus of elasticity of the samples.

Performance Evaluation for Cohesionless Soil Stabilized with Lignin and Polymerized Lignin

Abstract Lignin is a natural copolymer found in plants that is a major waste from bioenergy and paper industries. In this study, comprehensive laboratory testing programs were carried out to evaluate the strength improvements and water resistance of soil after being stabilized by lignin and polymerized lignin. The chemical polymerization of pre-treated lignin involves a process of linking short lignin molecules to form longer ones and consuming hydrophilic functional groups to improve its stability under wet conditions. Various testing combinations were considered, including four lignin or polymerized lignin contents (0, 6, 8, and 10 %) and four lime contents (0, 2, 4, and 6 %). The results show that lignin-stabilized soil will take at least 14 days to reach maximum strength, whereas the minimum curing period is 21 days for soil stabilized with polymerized lignin. The optimum dosage is 8 % when lignin or polymerized lignin is used for soil stabilization. Polymerized lignin can provide approximately 10 to 20 % more strength improvement than lignin; however, lime seems work better with lignin than polymerized lignin when added as a strength booster. The water soaking tests showed that polymerized lignin has better moisture resistance than lignin, and additional lime can further improve the performance of stabilized soil with respect to water susceptibility. However, the strength of specimens cannot fully recover, decreasing slightly after each dry–wet cycle for both specimens treated by lignin and polymerized lignin. The total decrease is about 5∼10 % after two cycles. The temperature and pH value control and oxygen supply approach used in this study will be an important reference for future studies.

Effects of soil amendments on soil acidity and crop yields in acidic soils: A world-wide meta-analysis

Soil amendments, including lime, biochar, industrial by-products, manure, and straw are used to alleviate soil acidification and improve crop productivity. Quantitative insight in the effect of these amendments on soil pH is limited, hampering their appropriate use. Until now, there is no comprehensive evaluation of the effects of soil amendments on soil acidity and yield, accounting for differences in soil properties. We synthesized 832 observations from 142 papers to explore the impact of these amendments on crop yield, soil pH and soil properties, focusing on acidic soils with a pH value below 6.5. Application of lime, biochar, by-products, manure, straw and combinations of them significantly increased soil pH by 15%, 12%, 15%, 13%, 5% and 17%, and increased crop yield by 29%, 57%, 50%, 55%, 9%, and 52%, respectively. The increase of soil pH was positively correlated with the increase in crop yield, but the relationship varied among crop types. The most substantial increases in soil pH and yield in response to soil amendments were found under long-term applications (>6 year) in strongly acidic (pH < 5.0) sandy soils with a low cation exchange capacity (CEC, <100 mmolc kg−1) and low soil organic matter content (SOM, <12 g kg−1). Most amendments increased soil CEC, SOM and base saturation (BS) and decreased soil bulk density (BD), but lime application increased soil BD (1%) induced by soil compaction. Soil pH and yield were positively correlated with CEC, SOM and BS, while yield declined when soils became compacted. Considering the impact of the amendments on soil pH, soil properties and crop yield as well as their costs, the addition of lime, manure and straw seem most appropriate in acidic soils with an initial pH range from <5.0, 5.0–6.0 and 6.0–6.5, respectively.

The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa.

Anthropogenic metal pollution can result in co-selection for antibiotic resistance and potentially select for increased virulence in bacterial pathogens. Metal-polluted environments can select for the increased production of siderophore molecules to detoxify non-ferrous metals. However, these same molecules also aid the uptake of ferric iron, a limiting factor for within-host pathogen growth, and are consequently a virulence factor. Anthropogenic methods to remediate environmental metal contamination commonly involve amendment with lime-containing materials. However, whether this reduces in situ co-selection for antibiotic resistance and siderophore-mediated virulence remains unknown. Here, using microcosms containing non-sterile metal-contaminated river water and sediment, we test whether liming reduces co-selection for these pathogenicity traits in the opportunistic pathogen Pseudomonas aeruginosa. To account for the effect of environmental structure, which is known to impact siderophore production, microcosms were incubated under either static or shaking conditions. Evolved P. aeruginosa populations had greater fitness in the presence of toxic concentrations of copper than the ancestral strain and showed increased resistance to the clinically relevant antibiotics apramycin, cefotaxime and trimethoprim, regardless of lime addition or environmental structure. Although we found virulence to be significantly associated with siderophore production, neither virulence nor siderophore production significantly differed between the four treatments. Furthermore, liming did not mitigate metal-imposed selection for antibiotic resistance or virulence in P. aeruginosa. Consequently, metal-contaminated environments may select for antibiotic resistance and virulence traits even when treated with lime.

Improvement of collapsing problematic soils on the sabzevar-mashhad railway route (northeast of Iran) using traditional additives

Collapsing soils are among the problematic soils in geotechnical engineering. These soils have a relatively good resistance in their natural state with low humidity, but in case of saturation without change in the incoming load or subjected to vibration force, they settle a lot and in many cases, it will cause cracking or destruction of foundations, roads, railway lines, dams, pipelines and other existing structures. Collapsing soils are scattered in many regions of the world, in Iran these soils are mostly observed in the central and eastern regions. In this research, according to the samples taken from Khorasan-Razavi province in the area of Sabzevar-Mashhad, these samples have been shown to be in the category of collapsing soils based on the tests performed according to ASTM standards. In order to improve this soil, cement and lime additives with percentages of 5 and 10 percent have been used, which has improved the shear properties of the soil due to the addition of lime and cement, so that it causes an increase in the friction angle in the soil, which indicates an improvement in the soil parameters. The results obtained with regard to the addition of cement and lime to the compacted soil show that the index of compaction in the addition of lime is better than that of cement and the results show that with the increase of lime, the soil has a 68% and 78% decrease in the soil compaction index, respectively, but when cement is added to the soil, it causes the percentage of raking index to improve by 34 and 37%.

Soil Stabilization by Using Lime and Fly Ash at Ahirwadi

Abstract: Soil stabilization is a crucial aspect of civil engineering, particularly in the construction of infrastructure projects. This study investigates the effectiveness of lime and fly ash as soil stabilizers and their combined application for enhancing soil properties. The objective of this research is to evaluate the changes in the geotechnical properties of soil treated with lime and fly ash, including compressive strength, shear strength, and durability. In this experimental study, different proportions of lime and fly ash were mixed with the soil samples to determine the optimal combination that yields the highest improvement in soil characteristics. The laboratory tests conducted on the stabilized soil samples included compaction tests and unconfined compressive strength tests. The samples were cured for different periods to assess the long-term performance and durability of the stabilization technique. The results indicate that the addition of lime and fly ash significantly improves the soil's engineering properties. The lime effectively increases the soil's pH, reducing plasticity and improving workability. The fly ash, on the other hand, enhances the pozzolanic reactivity and improves the soil's strength and durability. The combination of lime and fly ash demonstrates synergistic effects, leading to further improvements in the stabilized soil's properties.

Effect of Fortification of Massage Oil for Breastfeeding Mothers on Physical, Chemical and Organoleptic Tests of Jitu Oil

This massage oil is called Jitu Oil, which means complementary therapy massage oil. The addition of oil is expected to help facilitate the massage process and provide relaxation for nursing mothers, and can produce hormones that play a major role in the process of lactation and breastfeeding to the fullest. The oil used virgin coconut oil with the addition of lavender and lime to add relaxation during the massage process. This research is an experimental research with 5 treatments. The location of the research was carried out in the Working Area of the Arjasa Health Center. The time of the research was conducted from February to March 2023. The population in this study were breastfeeding mothers. The sample in this study consisted of 31 respondentused simple random sampling technique. The clarity test was found to be clear without impurities, the chemical test showed the substances contained in the oil and the organoleptic test p-value = 0.000 &lt;0.05, it can be concluded that there is a difference between the composition and the organoleptic quality parameters of color. If seen from the Mean Rank value, it shows that F5 is higher than the others. p-value = 0.000 &lt;0.05, it can be concluded that there is a difference between the composition of the organoleptic aroma quality parameters. If seen from the Mean Rank value, it shows that F4 is higher than the others. So that Jitu Oil can be widely used and produced to complement massage for nursing mothers.

H20 Gin or tonic: the dermatological hazards of cocktail-based quinine

Abstract Derived from Cinchona tree bark, quinine was first found to be beneficial to health by indigenous Amazonian peoples. Seventeenth-century Jesuit missionaries sent the bark and seeds back to Europe, where word of its therapeutic properties spread. Quinine was promoted as an antiseptic treatment for a range of ailments from the 1600s onward, including septicaemia, erysipelas and scarlet fever. The dermatological risks of quinine quickly became recognized, with Bartholow stating in his 1876 work that ‘The action of quinia has occasionally been attended by the appearance of an eruption on the skin. Sometimes the exanthem has been in the form of an erythema, sometimes it has assumed the appearance of urticaria.’ The pharmacological properties of quinine were exploited by colonial institutions such as the East India Company, who combined a pragmatic approach to antimalarial prophylaxis with a British penchant for aperitivos. The bitter taste of quinine in tonic water led to the addition of water, sugar, lime and gin, giving rise to the gin and tonic (G&amp;T). Its enduring popularity is, in part, due to the astringent nature of quinine and its acidic content that acts as a ‘stomachic tonic; that is, promote appetite, the flow of gastric juice, and the digestive power’. However, since its advent, the G&amp;T has been attributed to many cases of dermatological malaise, as discovered by this systemic review of the published PubMed and SCOPUS literature. To the adage ‘new drugs, new eruptions’, the G&amp;T was no exception. The first published skin reaction to quinine in tonic water dates from 1955, occurring shortly after the patient attended a cocktail party after which they developed ‘a burning sensation in the groins and in his hands and feet’ with progressive oedema and erythema to these areas, spreading to involve nearly all of the body. Other published cases describe (in decreasing frequency) fixed drug eruptions, photosensitive reactions, allergic urticaria and lichenoid drug reactions triggered by quinine in G&amp;Ts. The spectrum of eruptions triggered by tonic water extends to Stevens–Johnson syndrome/toxic epidermal necrolysis triggered by scotch and tonic water consumed at the patient’s peril during a convention in 1972. With an enduring popularity spanning two centuries, and a declaration from Churchill that ‘the gin and tonic has saved more Englishmen's lives, and minds, than all the doctors in the Empire,’ it is vital that dermatologists are aware of the potential dermatological hazards of the G&amp;T.

Measurement of lime movement and dissolution in acidic soils using mid-infrared spectroscopy

Acidification of surface and sub-surface soils limits agricultural production globally. Conventional surface application of lime is the most common amelioration approach for surface acidity. However, amelioration of sub-surface acidity is challenging to achieve using this approach. Testing the efficacy of liming to treat acidity through the soil profile via the measurement of lime movement requires high throughput information about soil properties at a high spatial resolution, which can be time consuming and expensive using traditional laboratory analysis. Here, we investigated the potential of Mid Infrared (MIR) spectroscopy as a tool to monitor lime dissolution and vertical movement through soils at high spatial resolution. Soil samples were collected at 2.5 cm intervals to 20 cm depth at three trial sites in South Australia, with various lime treatments applied either 6 years or 1 year prior to sampling. MIR Partial least squares regression (PLSR) predictions were undertaken to measure lime dissolution and alkalinity movement via soil pH, and undissolved lime presence via soil carbonate concentrations. Lime balance calculations were then performed to determine the fate of applied lime and assess efficacy of various rates of lime products applied at the surface only or via incorporation. MIR-PLSR prediction model performance was strong for both soil pH (R2 = 0.923 and RMSE = 0.202) and carbonate (R2 =0.829 and RMSE=0.042 CO3%). Results indicated the movement of alkalinity at all sites was limited, and revealed increased movement at the longer-term (∼6 years) vs shorter-term (∼1 year) sites where lime was surface applied. Lime balance calculations indicated that residual lime remained in the top 7.5 cm of the soil profile while soils remained acidic below this depth. Findings suggest that incorporation of residual lime and additional lime applications may be necessary to remediate sub-surface acidity. A decision tree was developed to inform management of surface and sub-surface soil acidity. The study validates the potential of MIR spectroscopy to measure and monitor the effectiveness and movement of lime with improved resolution in acidic soils.

Experimental and Numerical Studies of Viscoelastic Behavior of Bituminous Mixture with a High Rate of Reclaimed Asphalt Pavement, Dune Sand and Lime

Road construction is now a priority in the economic and social development policy of a country. The increased need to improve the infrastructure system and to counter the deficit in certain quarry gravels and non-renewable resources while saving increasingly expensive road investments, makes recourse to the use of abundant and inexpensive materials in order to reduce the use of non-renewable natural materials. The objective of this research is to predict the viscoelastic behavior of asphalt mixtures incorporating high Reclaimed Asphalt Pavement (RAP) content, allowing to reduce the consumption of new aggregates and bituminous binders, and other additives such as dune sand and lime. A new formula containing 3,7% of 35/50 penetration grade virgin bitumen, 40% of Reclaimed Asphalt, 10% of dune sand, and 1% of hydrate lime was tested and compared to the conventional formula containing 5,3% of the same virgin bitumen. To evaluate the impact of dune sand and lime addition on the mechanical behavior of bituminous mixtures containing high rates of RAP, complex modulus tests were conducted on the studied mixtures, at different temperatures and frequencies, using a two-point bending device that was developed at the National School of Engineers of Tunis. Their viscoelastic properties were determined using a Generalized Maxwell model which was calibrated by 2S2P1D model. The paper describes a three-dimensional Finite Element (FE) model developed using ABAQUS software, that is used to simulate 2-point bending tests on trapezoidal samples of the studied mixtures to determine their complex modulus and accurately predict their mechanical behavior under traffic loading at ranges of temperatures and frequencies that are not experimentally accessible. To validate the FE model, determined viscoelastic properties have then been introduced into through the Prony series and its outputs were validated by experimental measurements. Both experimental and numerical results show that the use of RAP, dune sand and lime greatly improves the rigidity of the mix at high temperatures. A suggested continuation of this work would be an investigation of the rutting resistance.

Soil tillage systems and forms of lime application on soil attribute enhancements in ratoon sugarcane

AbstractCombining deep tillage (DT) with lime application at greater depths may improve sugarcane yield. The objective of this study was to evaluate the impact of conventional tillage (CT) and DT systems and liming on sugarcane productivity and soil physical attributes. The experiment was conducted in a clayey‐textured Rhodic Hapludox soil cultivated with sugarcane for two growing seasons (first and third ratoons) using a randomized block design with four treatments and four repetitions. The treatments consisted of DT without liming (DT0), DT with liming (DT2), CT without liming (CT0) and CT with liming (CT2). In addition to sugarcane stalk and sugar yields, macroporosity (MA), microporosity (MI), total soil porosity (TP), weighted average diameter (WAD), aggregate stability index (ASI), soil penetration resistance (SPR), pH, potential acidity (H + Al), total soil organic carbon (SOC), particulate organic carbon (POC), mineral‐associated organic carbon (MOC), calcium (Ca) and magnesium (Mg) were analysed. DT2 promoted the best soil conservation effect on sugarcane. In general, DT, regardless of lime application, reduced SOC and POC in soil surface layer. Nevertheless, in the long term, localized lime addition resulted in significant reductions in compaction, reaching values below 2 MPa. The soil fertility improvement provided by DT2 promoted increased sucrose concentrations and stalks yield. Considering that there was an improvement in the physical quality and fertility of soil for better plant development, the deep tillage with localized lime addition can be considered an effective alternative for sugarcane cultivation.