LA Abrasion Research Articles

Evaluating the impact of reducing POFA’s particle fineness on its pozzolanic reactivity and mortar strength

This paper presents the effect of size reduction of palm oil fuel ash (POFA) in the nanoscale to improve the mortar strength. In this work, three different particle sizes of POFA prepared using the LA abrasion machine were used as a cement replacement. The physical and chemical properties, mineralogy, and morphology of all POFA specimens were studied. The effect of size reduction on the pozzolanic reactivity of POFA is also studied. The mortar mix design that contained micro and nano POFA was prepared and evaluated for its compressive and flexural properties at the ages of 7, 28, 56, and 90 days. Response surface methodology was used to evaluate the relationship between the factors (cement replacement) and responses (compressive and flexural strength), aiming to find the best mix design. The grinding method in this work produced POFA as small as 110 nm. The nano POFAs were observed to have better pozzolanic reactivity compared to micro POFA. The results show that nano POFA increased the mortar strength activity index by up to 20% compared to micro POFA. The best mix design was found using a combination of 10 and 3% of micro and nano POFA as cement replacement. The best mix design shows excellent early compressive strength (7 days) compared to other mixes, although the difference in long-term compressive strength is insignificant. Similar findings were observed for the flexural strength, whereby the best mix design was obtained using a combination of 10 and 3% of micro and nano POFA. This work may provide useful insight into the effect of size reduction on the pozzolanic reactivity of POFA.

Study of Characteristics of Bitumen and Aggregate with Use of Plastic Waste

Plastic is everywhere, and its use in different forms is increasing day by day despite discouragement from the government. Plastic waste disposal is a global issue since they are non-biodegradable and toxic in burning. Plastic pollution threatens food quality, human health, sanitation, and the ecosystem and contributes to climate change. The usage of plastic waste in elements (bitumen and aggregate) used in road construction was the main objective of this study. With use of appropriate plastic waste in building of road would not only reduce material cost but also contributes in solving plastic waste management issue. Nepal being a developing country with low Gross Domestic Product (GDP) where most of the districts are still deprived of good flexible pavement networks, plastic modified roads could be a value engineering and economic solution. The paper highlights by which method plastic waste can be used effectively in road construction by performing different experimental tests reflecting the characteristics of bitumen and aggregate on addition of plastic. The study has determined the penetration, softening point, ductility values of bitumen and impact and abrasion values of aggregate in addition to different percentage of plastic waste. According to the study, bitumen's penetration and ductility value drop with increasing plastic content, making it better suited for usage in warmer climates, but its softening point rises, ensuring a stronger resistance to flow in services. Comparably, when in aggregate plastic content rises, both its AIV value and its LA abrasion value fall, enhancing the aggregate's toughness and ability to endure greater wear and tear.

Suitability of Using LA Abrasion Machine for the Nano Manufacturing of Palm Oil Fuel Ash and Incorporating in Mortar Mixture

Background In order to enhance the properties of palm oil fuel ash-based mortar, researchers have explored the concept of reducing palm oil fuel ash (POFA) to a nanoscale. While previous studies have utilized ball milling machines with high grinding speed to achieve nano-scale POFA, the Los Angeles abrasion machine, which is more readily available and has a slower grinding speed, has been rarely employed. Objective The study aimed to investigate the suitability of using a Los Angeles abrasion machine with a low grinding speed to produce nano palm oil fuel ash. This paper also provides a comparison of the effect of using the nano POFA with different particle sizes within the range of 982 to 150 nm on the mortar’s flowability and compressive strength. Methods To produce nano-size palm oil fuel ash using the Los Angeles abrasion machine, the received palm oil fuel ash was thermally treated and ground using a Los Angeles abrasion machine with varying grinding periods. The grinding process parameters were kept constant, but second grinding periods of 50,000, 80,000, and 110,000 cycles were introduced. All three types of nano palm oil fuel ash were analyzed for their physical properties, chemical properties, morphology, and mineralogy. Furthermore, these nano palm oil fuel ashes were incorporated into a designed mortar mix along with micro palm oil fuel ash. The mortar’s fresh properties and compressive strength at different curing ages were observed and analyzed. The relationship between various factors, such as the replacement rate of micro, nano palm oil fuel ash, the grinding cycles of nano POFA, and the corresponding responses, specifically the compressive strength at different curing ages, was analyzed and explained using the response surface methodology. Results The 110k cycle nano palm oil fuel ash had a smaller particle size of 103.1 nm, while a particle size of 529 nm and 325 nm was found in the 50k and 80k cycle nano palm oil fuel ash. In terms of the combination of micro and nano palm oil fuel ash in the mortar, increasing the dosage of nano palm oil fuel ash contributed to improvements in flow diameter and compressive strength. However, the opposite trend was observed with micro palm oil fuel ash. The optimal mix design for the combination involved using 10% micro and 2 to 3% nano palm oil fuel ash. This composition led to an improvement rate of 7.9%, 1.48%, and 4.6% in compressive strength at 7, 28, and 90 days, respectively. While, the response surface methodology’s numerical optimization also supported the use of a similar combination. However, it additionally recommended employing the 50,000-cycle nano palm oil fuel ash in the mortar for earlier curing stages, while the 110,000-cycle nano palm oil fuel ash was suggested for later curing stages. Conclusion Los Angeles abrasion machine could be utilized to produce nano palm oil fuel ash with a particle size up to 103 nm with the aid of designed parameters. In this mortar mix design, the impact of a small variance in nano palm oil fuel ash’s particle size was trivial compared to the replacement rate of micro palm oil fuel ash on the mortar’s compressive strength.

The Structural Behavior of Reinforced Concrete Beams Made with Locally Produced Recycled Aggregate in the UAE

In this study, the feasibility of utilizing locally produced coarse recycled aggregate (RA) from demolition waste in the UAE for structural applications was investigated. A comprehensive literature review on the subject showed that the shear and flexural responses of reinforced beams utilizing aggregate from concrete demolition waste are greatly dependent on the aggregate replacement ratio and the quality of the recycled aggregate. The experimental program in this study consisted of three phases. Phase I focused on the evaluation of the physical and mechanical characteristics of the RA, Phase II addressed the mix design and fresh and hard properties of the concrete, and Phase III dealt with the flexural and shear behavior of structural members. The research involved twelve 150 mm × 300 mm reinforced concrete beams with a length of 1500 mm or 2000 mm that were made with 0% (control), 50%, or 100% recycled coarse aggregate, replacing natural coarse aggregate (NA). Two target concrete compressive strengths, 25 and 35 MPa, were considered in the investigation. The results showed that the recycled aggregates had lower crushing and LA abrasion values by 40% and 18–28%, respectively, whereas the absorption capacity was 40–300% higher compared to the natural aggregate. In addition, the mechanical properties of the concrete made with different replacement ratios (R%) of RA were either similar or slightly less than those of the control mix. The shear beam tests with fc′ = 25 MPa showed that the 50%- and 100%-replacement-ratio beams demonstrated closely matched normalized shear strength values that exceeded their corresponding NA beam by 12.5%, while the shear beam tests with fc′ = 35 MPa showed that the NA beam exhibited normalized shear strength surpassing the 50% RA and 100% RA beams by 12.5% and 17.5%, respectively. In the flexural beam tests, the flexural strength exhibited minimal disparities for the beams that shared the same RA% but differed in their compressive strength targets, and overall, the variation in the RA% had a marginal impact on the flexural strength of the beams. Further, an increase in the RA% corresponded to an increase in the shear ductility index, which was in contrast with the findings on the flexural ductility index. Furthermore, predictions of flexural strength using the ACI318-19 code and shear strength using the strut-and-tie model yielded comparable results to the experimental ones.

Physical, mechanical, chemical, and environmental characterization of stockpiled BOF slag as railway ballast material

Crushed stone from natural sources is commonly used as ballast in railways. The material is a good ballast, but its extraction is destructive. Therefore, this study characterizes basic oxygen furnace (BOF) slag as an alternative material for railway ballast in Kazakhstan with respect to physical, mechanical, chemical and environmental properties. The characterized BOF slags are of two types (top and bottom) with 10 years minimum age. Grain size distribution, specific gravity, absorption capacity, flakiness, lightweight particles, and 3D image analysis for forms and angularity were used for physical characterization. These BOF slags were found to have high specific gravity and a predominantly spherical shape, with larger particles displaying lower sphericity and greater angularity than smaller ones. The mechanical characterization of the BOF slag were carried out using various methods, including LA abrasion, Micro-Deval, aggregate crushing value, aggregate impact value, volumetric expansion, and fouling. BOF slag aggregates demonstrated exceptional strength with good resistance to fragmentation, crushing, surface abrasion, and sudden loading. The expansion rate is considerably lower than the standard limit, and the fouling rate is better than limestone and similar to granite. X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were all used for chemical characterization. Both BOF slags contain CaO and Fe2O3 with a high peak of SiO2 and portlandite, which suggests that most of the free lime has undergone hydration due to the natural aging of the BOF slag. Regarding the environmental characterization, the tests employed were organic impurity, freeze and thaw, and sodium-based soundness. No organic impurity was observed in the BOF slag, and the BOF slag demonstrated good resistance to weathering and degradation. The characteristics of the investigated BOF slag obtained from laboratory testing were analyzed to confirm its performance for implementation in railway ballast in compliance with the specific requirements, primarily the GOST standard, which is commonly employed in Russia and former Soviet republics, including Kazakhstan. As a result, both BOF slags demonstrated total compliance with the specifications, and the possibility of using stockpiled BOF slag for railway ballast material in Kazakhstan was established.

Relationship of petrographic and mineralogical characteristics with mechanical strength properties of granitic rocks: a case study from the Biga Peninsula, NW Turkey

This study was carried out on granitic rocks from the Biga Peninsula in order to investigate petrographic, and mineralogical properties in comparison with mechanical strength properties. This study was conducted in four different locations where granitic rocks outcrop from north to south in the Biga Peninsula: Lapseki (Şevketiye granite), Ezine (Kestanbol granite), Bayramiç (Yassıbağ granite), and Edremit (Eybek granite). Field observations and detailed petrographic studies of representative samples indicate that they are quartz monzodiorite (Şevketiye and Yassıbağ), quartz monzonite (Kestanbol), and granodiorite (Eybek) in composition. All the rocks have similar mineral composition, comprising mainly feldspar (plagioclase-alkali feldspar), quartz, mafic minerals (biotite and amphibole), accessory minerals (sphene, zircon, opaque minerals), and secondary minerals (sericite, epidote, chlorite) with differences in the percentage of modal mineralogy, textural details, and weathering. Physical and mechanical properties were also defined in this study, these include water absorption, porosity, uniaxial compressive strength (UCS), tensile strength (TS), Schmidt hardness tests (SHT), Los Angeles test (LA), and frost resistance test (FRT) with sodium sulfate (Na2SO4). The results of strength tests show that the Şevketiye granite had the lowest strength values with the highest values for Los Angeles abrasion, frost resistance, water absorption, and porosity. The Eybek granite exhibited the highest value for strength, with the lowest values for Los Angeles abrasion, frost resistance, water absorption, and porosity. A comparison of the petrographic properties of all studied rocks with their respective strengths show that modal mineralogy, degree of alteration, and texture influence the strength of the rocks. Additionally, an increasing propensity for UCS and TS values was found with increasing SHT values. The LA abrasion values and the FRT values were found to increase with decreasing Schmidt hardness test values for the tested samples. The found results of this study could help in the application of these rocks as row material.

The utilisation of End-of-Life Plastics for the production of paver blocks: A waste management and disposal strategy

The volume of municipal solid waste in developing countries continues to grow, yet disposal and management have become significant challenges. As a result, a proper disposal strategy is required. The feasibility of making paver blocks from plastic waste for construction work was investigated in this study. Paver blocks manufactured from plastic waste (PP and HDPE) and sand in varied proportions were evaluated for compressive strength, water absorption, and abrasion resistance. Paver blocks were manufactured with plastic (PP and HDPE) to sand ratios of 30:70%, 40:60%, 50:50%, 60:40%, and 70:30%, or PP30, PP40, PP50, PP60, and PP70, and HDPE30, HDPE40, HDPE50, HDPE60, and HDPE70. The paver blocks were inspected after 28 days. Compressive strength, LA abrasion, and water absorption of paver blocks increased from 30% to 40% HDPE, then fell to 70%. As paver block PP content grew from 30% to 70%, abrasion and water absorption decreased. The compressive strength of PP paver blocks declined from 30% to 50% PP, then increased somewhat, and then fell to 60% and 70% PP. PP60 and HDPE40 paver blocks had the highest compressive strength, abrasion value, and water absorption. HDPE40 pavers have lesser water absorption and more abrasion than PP60 pavers. PP60 water absorption and abrasion were 0.53% and 11%; HDPE40 was 0.03% and 24.2%. PP60 and HDPE50 have compressive strength, abrasion resistance, and water absorption of 20.09 MPa, 11%, and 0.53%, respectively, and 13.06 MPa, 12.1%, and 0.03%.

Effect of combining different surface treatments on the surface characteristics of polyetheretherketone-based core materials and shear bond strength to a veneering composite resin

Statement of problemHigh-performance polyetheretherketone (PEEK) has been used in dentistry because of its excellent physical and chemical properties. However, its lack of translucency requires the use of a veneering composite resin for esthetic applications. Data on bonding a veneering composite resin to PEEK are still scarce. PurposeThe purpose of this in vitro study was to assess the effect of using and combining different surface treatments on the surface roughness and wettability of PEEK core materials and the shear bond strength (SBS) to a veneering composite resin. Material and methodsSixty square PEEK specimens were divided according to surface treatments into 6 groups: group N, no surface treatment; group A, airborne-particle abrasion; group L, ER:YAG laser treatment; group LA, laser treatment and airborne-particle abrasion; group P, plasma treatment; and group PA, plasma treatment and airborne-particle abrasion. Surface roughness (Ra) and wettability (contact angle θ) were measured followed by evaluation of the surface topography. After veneering, the SBS was measured. A 1-way analysis of variance (ANOVA) was used to assess all interactions with multiple pairwise comparisons (α=.05). ResultsThe highest mean Ra values were obtained for the combination treatment groups (LA 2.94 ±0.1 and PA 2.7 ±0.1 μm) (P<.001). While the laser (1.3 ±0.1 μm) and plasma treatment (1.4 ±0.1 μm) groups had the lowest Ra values, LA and PA had the highest wetting of PEEK surfaces (LA 6.9 ±0.7 and PA 4.9 ±0.2 degrees) (P<.001). The highest mean SBS values were demonstrated on PEEK surfaces with combination treatments (LA 22 ±1.3 and PA 21.2 ±0.8 MPa) (P<.001). ConclusionsCombining airborne-particle abrasion with laser or plasma treatments increased the surface roughness and wettability of PEEK surfaces favorably compared with applying each of the 3 treatments individually. The combinations enhanced the bond strength of PEEK to the veneering composite resin.

Performance of Stone Mastic Asphalt incorporating Kenaf fiber

Stone mastic asphalt (SMA) is a type of gap-graded asphalt mixture that contain large gap between big size and small size of aggregate. These criteria tend to reduce the tensile strength of mixture. To solve this, SMA usually mixed with synthetic fiber to increase tensile strength. However, synthetic fiber is costly and rarely obtained from local supplies. Thus, the aim of this study is to utilize different percentages of natural fiber which is kenaf fiber in SMA to overcome issues related to SMA. Among the test involved were LA Abrasion, Marshall Stability, Resilient Modulus, and Dynamic Creep. From the results, it shows that the addition of 0.2% fiber contributes to lowest value of abrasion. In addition, 0.2% fiber also produces the highest density of SMA20 (Stone Mastic Asphalt Grade 20). It could be seen that 0.6% of kenaf fiber producing highest value of resilient modulus. Dynamic creep also shows a significant value for 0.2% amount of kenaf fiber. Thus, it can be concluded that the existence of fiber is capable in enhancing the performance of SMA which is evident for instance, the density. The outcome of this study also contributes to the improvement of current guideline in designing SMA mixture especially for Public Work Department of Malaysia.

Volumetric Properties and Abrasion Resistance of Stone Mastic Asphalt Incorporating Eggshell Powder

Stone Mastic Asphalt (SMA) is designed to improve durability and life span of road pavement through the use of a stable stone-on-stone skeleton held together by a rich mixture of asphalt. However, over time the structure is subjected to damage from cracking, rutting, stripping and rapid aging under the effects of repeated vehicle loading, hot climates and heavy rainfall. Previous studies proved that eggshell is capable to enhance the strength and durability of concrete. Thus, the aim of this study is to evaluate the performance of these stone mastic asphalt mixtures with the eggshell powder and overcome the issue that is related to SMA. A mixture contains varying percentages of eggshell powder were assessed to check which samples gives the best performance as per the requirement by using laboratory tests which are LA Abrasion and volumetric properties. Results indicated that eggshell powder can effectively recover and enhance abrasion resistance of asphalt and increases the marshal stability of SMA. SMA mixtures modified with eggshell powder produce the performance enhancement of SMA as a road surfacing material. It is concluded that the asphalt mixtures containing eggshell powder could be increases the stability and strength of the mix.

Abrasion Characteristics of the Coarse Aggregate Exposed to the Road Surface Using LA Abrasion Test and Accelerated Polishing Test

Abrasion Characteristics of the Coarse Aggregate Exposed to the Road Surface Using LA Abrasion Test and Accelerated Polishing Test

Stability and Resilient Modulus of Porous Asphalt Incorporating Steel Fiber

Porous Asphalt (PA) is known as a highly permeable asphalt surface that design to be permeable pavements for stormwater control and reduce the stormwater runoff. However, the structure is subjected to damage from cracking, rutting, stripping, and rapid aging under the effects of repeated vehicle loading, hot climates, and heavy rainfall. To overcome this, PA needs to modify using high tensile strength like steel fiber. Thus, this study aims to evaluate the performance of PA with the addition of steel fiber and overcome the issue that is related to PA. A mixture contains varying percentages of steel fiber were assessed to check which samples gives the best performance as per the requirement by using laboratory tests which are LA Abrasion, Resilient Modulus, Marshall Stability, and Density. The results show that the additions of 0.6% steel fiber give the lowest value of abrasion, while 0.5% fiber content contributes the highest value of Resilient Modulus and Marshall Stability respectively. PA mixtures modified with steel fiber produce the performance enhancement of PA as a road surfacing material. It is concluded that the asphalt mixtures containing steel fibers could increase the stability and strength of the mix.

Characterization of agglomeration of reclaimed asphalt pavement for cold recycling

Agglomeration of reclaimed asphalt pavement (RAP) is one of the most important factors affecting performance of cold recycled asphalt mixture. This research is conducted to evaluate the agglomeration of RAP collected from various sources including both raw milled-off and plant-crushed RAP. Three different test methods were used to examine the breaking of agglomerates of RAP, including asphalt extraction test, modified LA abrasion test and mixing test. LA abrasion revolution of RAP samples was performed at various rotations of 50r, 100r, 200r and 300r, and mixing test was performed at different mixing time of 0.5 min, 1 min, 2 min and 3 min. Effects of the testing conditions and plant-crushing on RAP de-agglomeration were evaluated. The obtained results showed that all three tests could effectively reflect the agglomeration property of RAP materials. Good correlations were found among results of the three tests, while abrasion test and mixer test typically have lower loss% than asphalt extraction test. A general indicator of agglomeration degree was proposed for the tests to describe the agglomeration property of RAP and a classification method of RAP particles was proposed based on the results and findings in the tests. Weak structure of RAP has significantly higher agglomeration degree, while old aggregate has very low agglomeration degree. It is suggested to reduce content of weak RAP in the cold recycling process due to its negative impact on the performance of regenerated mixture.

Aggregate Performance on Forest Roads in the Pacific Northwest

Eleven aggregate quarries from the Pacific Northwest, USA were sampled to measure the variability in rock properties. Additionally, road managers were asked to classify the aggregate source as good or marginal for forest roads with year-round timber hauling as the primary use. Seven of the eleven quarries were classified as good. A series of materials property tests were performed on the aggregate sampled from each quarry. The test included gradation, LA Abrasion, Micro-Deval, and sand equivalency tests. Three replicates were performed for the LA Abrasion, Micro-Deval, and sand equivalency tests. The results show that only two of the seven rated as good samples met the thresholds established from the literature review. None of the marginally rated aggregates met the thresholds for the material property tests. The results show that the road managers expectation of rock quality is inconsistent when compared with the results from tests. It suggests that in order to understand aggregate performance better, testing before placement is a necessity.

Characterization of building derived materials for partial replacement of pavement subgrade layer

This study investigates the potential of BDM in its virgin state for enhancing the geotechnical and mechanical properties of soft non-swelling soil with low shear strength. A series of material and geotechnical tests carried out on soil replaced with different percentages of BDM include specific gravity, water absorption, standard Proctor’s test, permeability test, aggregate impact test (AIV), Los Angeles abrasion test, and large shear box test. The results indicated that an optimum of 18–23% of BDM by weight can be added to soil to improve its mechanical and geotechnical properties such as shear strength and compaction. This study also evaluates the compatibility of BDM in soils from sites surrounding chemical plants. For this purpose, the BDMs are exposed to sulfuric, hydrochloric, and nitric acid solutions to identify the effects of these acids on the BDM behavior. It is observed that the strength of BDM decreases after their exposure to these solutions, with maximum effect manifested by nitric acid and least by hydrochloric acid. The results of AIV and LA abrasion test on BDM exposed to chemicals show that the performance of the BDM deteriorates in the presence of chemicals. The results obtained from the proposed study can be used to promote the practical use of BDM in geotechnical applications. However, necessary precautions must be adopted for their practical application in ground improvement based on soil conditions.

Effects of fine aggregate abrasion resistance and its fineness module on wear resistance of Portland cement concrete pavements

In this research, effects of fine aggregate abrasion resistance and its fineness module on wear resistance of Portland cement concrete pavements studied. Concrete samples included fine crushed limestone aggregate, fine crushed limestone-basalt mixture, and fine crushed basalt aggregate. The study results showed that LA abrasion rate of 30 % or less of fine aggregates would be necessary for long lasting concrete roads. Furthermore, it was found that fine aggregate’s fineness module of 3.15 will significantly increase concrete road surface’s wear resistance. As the fine aggregate’s fineness module value increased from 2.2 to 3.15, the concrete’s wear amount decreased to 15.5 %. Study findings also showed that using basalt aggregates instead of widely used limestone aggregates, will significantly increase pavement concrete wear resistance.

Influence of Recovery Processes on Properties of Binders and Aggregates Recovered from Recycled Asphalt Pavement

Abstract Usage of recycled asphalt pavement (RAP) in the construction of new pavements has increased in recent years due to the movement to conserve energy and raw materials, and reuse waste materials. To assess the effectiveness of RAP materials in new asphalt mixes, it is important to evaluate the properties of the recovered binders and aggregates. The widely used “Abson” method is employed in this study to recover asphalt binder from RAP. Also, the frequently used “NCAT ignition” method is used to extract aggregates. A laboratory study comprising two field RAP materials, two simulated RAP materials, and corresponding virgin materials was undertaken to assess possible influences of the aforementioned recovery processes. The performance grade (PG) of the recovered binders, and gradation, durability (LAAbrasion and Micro-Deval), specific gravity, sand equivalent, and insoluble residue of the extracted aggregates were evaluated as per the AASHTO and Oklahoma Dept. of Transportation (ODOT) standards. The test results showed that the Abson method notably influenced the critical PG temperatures of the recovered binder. It was also observed that some mechanical properties (durability and sand equivalent) of RAP aggregates were inconsistent with their virgin counterparts. Furthermore, field RAP aggregates showed significant variations in LA Abrasion loss and insoluble residue test results. The findings of this study are expected to be helpful in the evaluation of RAP for reuse in asphalt paving.

Recycling of construction and demolition waste via a mechanical sorting process

Abstract This paper assesses a construction and demonstration (C&D) waste recycling program in relation to technical, institutional, and economic considerations. The focus is primarily placed on a feasibility study for a new mechanical sorting process that was installed with several unit operations, including bar screening, trommel screening, air classifier, disk screening, and final manual sorting. Lab analyses, consisting of sieve analysis, LA abrasion test, friability test, organic content test, and fineness test, with respect to three types of product streams (A, B, and C) were conducted in accordance with selected physical and chemical properties. Findings clearly indicate that the reuse of fine particle generated in product stream A as construction materials in roadbed is highly recommended if the impurities can be removed beforehand. The product stream B could be suitable for reusing as the covering materials in daily operation of sanitary landfills. Yet it could also be used as backfill materials in the construction projects if the impurities can be removed in advance. Only does the LA abrasion test support the reuse of product stream C as coarse aggregate or pavement subbase for those new structures. Once the secondary materials market is stable and the institution settings are sufficient, it is worthwhile addressing that the associated cost-benefit analysis does confirm the economic potential for such a management practice.