Amount Of Lime Research Articles

Remediation of Spent Vegetable Tannins from Waste Tanning Liquor through Coagulation and Ultrasound Pre-Treatment

Vegetable tanning is one of the oldest methods of tanning. Vegetable tannins present in spent tanning liquor necessitates suitable remediation measures for sustainable solution. Vegetable tanning agent, wattle extract powder and vegetable tanning process spent liquor collected from a commercial tannery were used for the experiments. In the present approach, natural clay has been employed for the coagulation of spent vegetable tannins. Various other suitable precipitating agents such as zinc chloride (ZnCl2), barium chloride (BaCl2), ferric alum, lime and poly-electrolyte have also been studied for their efficacy in the treatment process and their requirement optimized. The efficacy of coagulation was monitored through settling characteristics of precipitation process and % settled volume for a given time. In the case of wattle powder, better settling of tannins was obtained due to combined use of optimized amount of clay and ZnCl2. Whereas, ultrasound pre-treatment provided further enhancement. In the case of spent tannery vegetable tanning liquor, ultrasound pre-treatment of polyelectrolyte along with optimized amount of normal lime, clay and ferric alum provided rapid settling behavior, with steady state achieved in 20 minutes with settled volume of ~10 ml. Similar trend was also achieved (10 ml, 8 min.) for ultrasound pre-treated optimized clay with the use of other agents as normal. There was a significant reduction in particle size of clay (from 539 nm to 298 nm) through ultrasound pre-treatment (20 min.), leading to more surface area facilitating the coagulation process. This method could be useful for remediation of vegetable tannins present in spent vegetable tanning liquors using available natural material clay and shall also be extended to other streams. The present study has explored the ultrasound assisted coagulation science and technology for remediation of wastewater in general, whereas, spent vegetable tanning liquor in specific.

Reuse of Taza marl-limestone in Morocco for road construction

To expand and maintain the Moroccan road network, millions of tonnes of aggregates from natural resources are extracted annually. This has a major impact on the environment and natural environments, namely, a disturbance or disappearance of the ecosystems of the rivers in which the materials are taken, a reduction in natural aggregate reserves and an extension of open-air quarries. For this purpose, the recovery and reuse of the materials in place by a specific treatment become more important. However, Moroccan regulations exclude very plastic soils with changing characteristics, which are generally fragmentable and degradable materials.The soils constituting the road accesses and the platform of the wind energy project of the city of Taza in Morocco are evolving marls-limestone. These materials are the subject of our research subject to see the possibility of their reuse. The first step of this research topic is the realization of a characterisation of marls-limestone of Taza, in order to identify the materials by physical, mineral and non-destructive testing. The second stage concerns the valorization of this evolving material with additives to improve the intrinsic characteristics of these soils, and check the possibility of reuse in embankments and earthworks. This improvement consists in measuring the cohesion, the friction angle and the bearing capacity of the materials, as well as giving the optimum amount of lime for practical design.

STABILIZATION OF BLACK COTTON SOIL WITH WASTE PLASTIC STRIPS

Black cotton soil is fine textured and clayey in nature. It has high amounts of lime, iron, magnesium and generally low quantities of phosphorus, nitrogen and organic matter.In this project an attempt is made to reinforce and stabilize black soil with plastic bottle strips. The plastic strips were prepared and added at different mixing ratio (2%,4%,6%,8% and 10%) by weight and in aspect ratio(2mm*10mm).The experimental results showed that there was a significant improvement in shear strength parameters. The swelling and desiccation cracking behavior of the soil were also expressively reduced. There was a substantial reduction in the optimum moisture content and slight increment in maximum dry density. The optimum plastic content that results in optimum result can be selected based on the importance of the selection parameter for a specified engineering work. Stabilizing Black soils with waste plastic bottles simultaneously solves the challenges of improper plastic waste recycling that is currently a teething problem in most developing countries. The results obtained from this study favorably suggest that inclusion of this material in expansive soils would be effective for ground improvement in geotechnical engineering. Keywords: Black cotton soil, Plastic strips, Soil stabilization, Ground improvement

Three amendments reduced the bioavailability of heavily contaminated soil with arsenic and cadmium and increased the relative feeding value of Lolium perenne L.

Soils heavily contaminated with arsenic (As) and cadmium (Cd) are fully utilized and create economic value by growing forages with high standard limits for heavy metals. In this study, 0.5 %, 1 % and 2 % of applied amounts of lime + ferrous sulfate (LF) and 0.25 %, 0.5 % and 1 % of applied amounts of Fe-modified biochar (MB) and Fe-modified eucalyptus sawdust (MC) were added to As and Cd cocontaminated soil planted with ryegrass (Lolium perenne L.). The results showed that the amendment-induced changes in soil pH and cation exchange capacity (CEC) contributed to the reduction in soil available Cd, which was maximally reduced by up to 76.7 %, 27.6 % and 25.1 % under the LF, MB and MC applications, respectively. In contrast, the available As content was reduced by a maximum of 25.5 % and 23.7 % under the MB and MC treatments, respectively, while LF did not reduce the available As content of the soil. As uptake by ryegrass was not reduced under the LF treatment, but As and Cd contents in the ryegrass shoot were reduced simultaneously under the MB and MC treatments. The relative forage value of ryegrass was enhanced more by MB and MC than by the LF treatment. The lime and ferrous sulfate components of LF could be immobilized against Cd and As, respectively; by characterizing MB and MC, the more available As and Cd fractions of the soil could be converted to less available fractions by electrostatic attraction, surface precipitation or complexation and redox. These results show that the application of amendments to heavily As and Cd cocontaminated soils in combination with ryegrass cultivation can help reduce the toxicity of As and Cd and increase the RFV, a model that may be a novel solution for heavily contaminated As and Cd cocontaminated soils.

Performance and microstructure development of lime – calcined fluvial sediment binders under different curing conditions

Fluvial sediments need to be periodically dredged from waterways. At the same time, the building sector has to find high-volume alternatives to the extraction of non-renewable mineral resources. In this context, recent research has shown the benefit of reusing calcined sediments as supplementary cementitious materials. On a different note, this study examines the hydration and performance of blends of calcined fluvial sediment with low amounts (10 to 30 wt%) of hydrated lime with the aim of keeping the carbon footprint of the binder the lowest as possible. The effect of different curing conditions (moist curing at 20 °C or 50 °C and dry curing at 65%RH) is studied on compressive strength, reaction kinetics (fixed lime by TGA and heat of hydration), reaction products (XRD), microstructure (SEM) and porosity (MIP). The outcomes of the study revealed that heat curing for 3 days and 10 wt% of lime results in satisfactory strength development for the design of bio-based concretes (compressive strength of 9 MPa). Furthermore, the highest compressive strength of 17.5 MPa was achieved at 110 days at 20 °C for the mix with 20 wt% of lime. The amount of unreacted lime was found to be the highest for the mix including 30 wt% of lime for which the degree of reaction of lime at 90 days was around 0.7 for both curing temperatures. Under dry curing, a large part of the initially available lime was carbonated and some reaction products underwent carbonation leading to very low strength by 110 days.

An integrated management strategy for acid mine drainage control of sulfidic tailings

The oxidation of sulfide minerals releases acidic leachate enriched in sulfate, iron, and toxic metals and metalloids (e.g., As, Sb, Cu, Pb, Cd, Zn, Hg, etc.) known as acid mine drainage (AMD). This eco-hydrological hazard is imminent when mineralogical and geochemical analysis indicates that acid-generating (sulfides) overcome the acid-neutralizing (carbonate) minerals in the ore and mining waste. AMD represents a multifaceted problem faced by the mining industry. The most widespread management technique is to store the tailings into engineered impoundments and actively neutralize the acidity produced by the oxidation of the sulfide minerals by adding alkaline chemical agents. However, this method involves a constant and long-term commitment, elevated operational costs, and several geotechnical and environmental drawbacks. In a pre-mining stage, geological, geochemical, mineralogical, and textural characterization of the mine waste could guide proper and site-specific mining waste management.In this paper, we present an integrated strategy to reduce the acid mine drainage (AMD) potential of the Dundee Precious Metals Chelopech (DPM-Ch) tailings through a combination of environmental desulfurization and cemented paste backfill (CPB) – the latter one being already practiced on-site. In the proposed scenario, a desulfurization plant would be installed downstream to re-float the non-valuable reactive pyrite. The reactive pyrite concentrate would be combined with the CPB material, whereas the remaining tailings would be discharged at the tailings management facility (TMF). The lack of neutralizing gangue (NP of untreated tailings < 8 kg CaCO3/t) precludes converting the tailings into non-acid generating. However, reducing nearly six times the amount of lime required to neutralize the acidity produced by pyrite oxidation was feasible without substantially increasing operational costs. Supporting the environmental benefits of combining desulfurization and backfill, an X-ray mapping of the CPB material revealed that this approach effectively encapsulates the reactive gangue, ultimately avoiding pyrite oxidation and leaching of heavy metals.

Application and depression mechanism of sodium sulfite on galena-pyrite mixed concentrate flotation separation: Huize Lead-Zinc Mine, China, as an example

Galena, sphalerite, and pyrite are important metallic sulfide minerals and are often associated with one another. In the flotation separation of galena-pyrite mixed concentrate, large amounts of lime (CaO) are used for the depression of pyrite. In this study, the negative effects of lime were reduced by using an efficient depressant Na2SO3 + CaO reagent in the flotation separation of galena from pyrite. Real ore sample flotation separation tests showed that the mixed depressant can efficiently depress pyrite from galena-pyrite mixed concentrate. The obtained galena concentrate had a Pb recovery and grade of 58.36% and 83.45%, respectively. Micro-flotation experiments showed that Na2SO3 depressed the floatability of pyrite more strongly than that of galena. Moreover, the depression mechanism of Na2SO3 was observed through contact angle measurements, ultraviolet–visible spectrophotometry (UV–Vis) analysis, and time of flight secondary ion mass spectrometry (TOF-SIMS). This study provides an important reference for the depression of pyrite from a galena-pyrite mixed concentrate with low lime dosage.

Influence of Rice Husk Biochar and Lime in Reducing Phosphorus Application Rate in Acid Soil: A Field Trial with Maize

Biochar has been suggested for application in acidic soils for increasing agricultural productivity, as it may result in the benefits of sustainable carbon offset into soils and of increasing soil fertility improvement. However, the role of biochar in enhancing nutrient bioavailability and plant performance is manifested through the complex interactions of biochar-soil-plant. Moreover, it is not yet known how a crop-residue-derived biochar would perform in acidic soil when applied with a reduced rate of lime and phosphorus. Here, we examined the performance of maize with different combinations of biochar, lime, and phosphorus (P) application rates under field conditions. Specifically, rice husk biochar (10 t ha−1) was applied with 75% of the required lime and three rates of phosphorus fertilizer (100%, 75%, and 50%). The results showed that incorporation of biochar and lime, irrespective of the rates of P application, significantly increased soil nutrient (nitrogen and P) availability, while aluminum (Al) and iron (Fe) concentrations in soil were reduced. Furthermore, when biochar was combined with a lower amount of lime (75% of the recommended amount) and half of the required P, maize production increased by 62.38% compared to the control. Similarly, nutrient uptake in plants increased significantly in the same treatment (e.g., P uptake increased by 231.88%). However, soil respiration (CO2 emission) increased with lime only and the combined application of lime with biochar compared to the control; these treatments resulted in a higher carbon loss, as CO2 from the soil (84.94% and 67.50% from only lime treatment (T2), and rice husk biochar (RHB) and lime with 50% triple superphosphate (TSP) (T5), respectively). Overall, our findings imply that biochar application may sustain productivity in acid soils even when lime and P fertilizer applications are made at a reduced rate.

Effect of 46 years' application of fertilizers, FYM and lime on physical, chemical and biological properties of soil under maize–wheat system in an acid Alfisol of northwest Himalayas

AbstractImbalanced fertilizer use with intensive cropping has threatened the sustainability of agroecosystems, especially on acid soils. An understanding of the long‐term effects of fertilizers and amendments on soil health is essential for sustaining high crop yields. The effects of application of fertilizers, and amendments for 46 years on soil properties and maize yield in an acid Alfisol were investigated in this study. Ten fertilizer treatments comprising different amounts of NPK fertilizers, farmyard manure (FYM) and lime, and one control, were replicated three times in a randomized block design. At 0–15 cm soil depth, bulk density was least (1.20 t/m3), porosity (49.8%) and water holding capacity (61.7%) were greatest in 100% NPK + FYM, corresponding to the largest organic carbon content (13.93 g/kg). Microbial biomass C and dehydrogenase activity in 100% NPK + FYM were 42% and 13.7% greater than 100% NPK, respectively. Available nutrients were significantly more with 100% NPK + FYM and 100% NPK + lime than control and other fertilizer treatments. At 15–30 cm depth, the effect of various treatments was comparable to the surface layer. Grain yield declined by 55% and 53% in 100% NPK(‐S) and 100% NP, respectively, compared with 100% NPK, whereas 100% N as urea alone eventually led to crop failure. Soil porosity recorded the greatest positive correlation (r = .933**), whereas bulk density recorded a negative significant correlation (r = −.942**) with grain yield. The results suggest that integrated use of FYM/lime with chemical fertilizers is a sustainable practice in terms of crop yield and soil health, whereas continuous application of urea alone is detrimental to the soil health.

Impact of fish culture value chain development project on production, pond area, employment creation, and technical capability of participating farmers in some areas of Natore district, Bangladesh

This study examines the impact of the fish culture value chain development project of PKSF (Palli Karma Sahayak Foundation) implemented by United Development Initiatives for Program Action (UDDIPAN) on fish farmers in the Natore district. The project period was 20 months. With the views in mind, 600 project participating fish farmers were selected purposively from the study area. It is evident that 15.53% of farmers used lime regularly as a precautionary measure against fish stocks in their ponds but 84.46% of farmers applied lime irregularly. At present, 100% fish, farmers apply a moderate amount of lime during the preparation of fish farming ponds. The final assessment survey found that fish feeding increased by 95% of the farmers used regular and 5% of the farmers applied irregular food. The final fish marketing capabilities increased by 58.58% sold fish from farms, 20.32% from local markets, and 21.12% from national markets. Fry marketing increased by 83.57% sold fry to farmers, 16.27% to potters, and 6.18% to other places. Water change increased by 90% of the farmers change the water regularly and 10% of the farmers change the water irregularly in the pond after participating in the fish culture value chain development project of PKSF implemented by UDDIPAN. Fish production has been 14.77 kg per decimal in the pond. Finally, the study concludes that PKSF on fish culture value chain development project had positively influenced production, pond area, employment generation, and technical capability of participating farmers in the project area.

Evaluation of marine dredged sediment as reactive powder compared to ground basaltic pyroclastic materials for the development of eco-friendly lime-pozzolan binders

The combination of lime with natural pozzolans for the production of binders in masonry construction dates back to ancient times. These were largely ignored with the industrialization of the building sector even though their use for specific applications is of interest. The use of lime-pozzolan binders with the least amount of lime is a relevant opportunity to reduce carbon emissions due to the decarbonation of limestone for the production of quicklime but also to introduce new alumino-silicate materials. In this context, the present investigation intends to relate marine dredged sediment to pyroclastic materials and to mix it with hydrated lime without any thermal treatment but after micronization. The blends were moist cured either at 20 °C or 50 °C and the paper will discuss the pozzolanic reactivity through the study of compressive strength and reaction kinetics from 3 days to 180 days. Reaction product assemblage, microstructure, and porosity refinement were also addressed after advanced curing ages. Results have well illustrated the long-term pozzolanic reactivity of the marine sediment cured at 50 °C through the whole combination of initially available lime after 60 days and the compressive strength development providing 12 MPa after 180 days.

Synergistic Repair Effect of Calcite-Based Passivator and Low-Accumulation Maize

In this study, a field experiment of soil passivation and low accumulation-crops was carried out for typical northern alkaline cadmium and lead compound-polluted farmland soil. Calcite was used as the main passivation material, and a small amount of slaked lime, zeolite powder, and biochar were combined to form a group passivation agent. The effects of passivators on soil physicochemical properties, bioavailability of the heavy metals Cd and Pb, and the yield and plant (stalk and seed) content of heavy metals Cd and Pb in low-accumulation maize were investigated under different grouping conditions of calcite+slaked lime (CL), calcite+zeolite (CZ), calcite+biochar (CB), and calcite+slaked lime+zeolite+biochar (CLZB). The results showed that:① all applications of passivating agent ensured the normal growth of maize and slightly increased the 1000 grain weight and maize yield. ② The effects of different calcite-based passivators on soil physical and chemical properties were different. The CL, CZ, CB, and CLZB treatments increased soil pH by 0.46, 0.25, 0.12, and 0.13 units, respectively, but had no significant correlation with soil fertility index (P>0.05). ③ DTPA leaching and ion exchange state contents of Cd and Pb in soil could be significantly reduced by different calcite-based combinations with passivators, and the reduction rates of Cd and Pb in DTPA leaching were 49.36% and 72.55%, respectively. The reduction rates of ion exchange Cd and Pb contents were 55.39% and 78.52%, respectively. ④ The contents of Cd and Pb in stems, leaves, and grains of low-accumulation maize were further reduced by different passivating agents. The contents of Cd and Pb in the stems and leaves of maize were reduced by 45.93% and 67.00% after CLZB treatment, and the contents of Cd and Pb in grains were decreased by 25.17% and 46.62%, respectively. Moreover, the contents of Cd and Pb in DTPA extraction and ion exchange states were significantly positively correlated with the contents of Cd and Pb in corn stems, leaves, and grains (P<0.01). The results showed that the combined use of combination passivators and low-accumulation crop varieties can obtain better restoration effects in the remediation of cadmium and lead combined-polluted farmland in the middle alkaline soil in northern China.

Methanogenesis from Mineral Carbonates, a Potential Indicator for Life on Mars

Priorities for the exploration of Mars involve the identification and observation of biosignatures that indicate the existence of life on the planet. The atmosphere and composition of the sediments on Mars suggest suitability for anaerobic chemolithotrophic metabolism. Carbonates are often considered as morphological biosignatures, such as stromatolites, but have not been considered as potential electron acceptors. Within the present study, hydrogenotrophic methanogen enrichments were generated from sediments that had received significant quantities of lime from industrial processes (lime kiln/steel production). These enrichments were then supplemented with calcium carbonate powder or marble chips as a sole source of carbon. These microcosms saw a release of inorganic carbon into the liquid phase, which was subsequently removed, resulting in the generation of methane, with 0.37 ± 0.09 mmoles of methane observed in the steel sediment enrichments supplemented with calcium carbonate powder. The steel sediment microcosms and lime sediments with carbonate powder enrichments were dominated by Methanobacterium sp., whilst the lime/marble enrichments were more diverse, containing varying proportions of Methanomassiliicoccus, Methanoculleus and Methanosarcina sp. In all microcosm experiments, acetic acid was detected in the liquid phase. Our results indicate that chemolithotrophic methanogenesis should be considered when determining biosignatures for life on Mars.

Engineering properties of very high volume fly ash composite

ABSTRACT The addition of a small quantity of lime has been recommended to enhance the early strength of High-Volume Fly Ash Concrete. However, the quantity of lime may not be adequate in the case of Very High Volume Fly Ash Concrete (VHVFAC). This study compares the mechanical properties of VHVFAC with 80% cement replacement with ultrafine fly ash with the addition of lime and silica fume (SF), with that of PC concrete over a 90-day period. Correlation between the compressive strength and other mechanical properties of VHVFAC are presented. The use of SF enhanced the mechanical properties of the VHVFAC, with the increase more predominant at early age. VHVFAC exhibited similar mechanical performance with PC concrete by the end of the 90 days.

Effects of Liming on Soil Properties and Its Roles in Increasing the Productivity and Profitability of the Oil Palm Industry in Malaysia

As global demand for edible oil increases, palm oil-producing countries in Southeast Asia are experiencing a rapid expansion of agricultural land for industrial oil palm cultivation by converting existing agricultural lands and some tropical rainforests; however, soil acidity and nutrient depletion are two major constraints in oil palm cultivation in the tropics. Several factors may cause soil acidification, including natural processes, industrial pollutants and extensive agricultural production. Soil acidity increases the leaching of many essential plant nutrient elements and the availability of toxic elements by modifying various geochemical and biological reactions in the soil. Even though acidic soil is less fertile, the productivity of tropical soil is among the highest in the world once the chemical constraints are removed by applying a sufficient quantity of lime and fertilizers. Lime is a widely used alkali to improve soil fertility by retaining nutrients, increasing soil biota, decreasing heavy-metal availability and potentially achieving resistance against Ganoderma disease at oil palm estates. Liming materials are not simple compounds with consistent chemical properties; thus, selecting the appropriate lime must be based on soil type and price compared to the products neutralizing value, composition, and fineness. Since the primary aim of liming is to improve soil pH, numerous reviews have been reported on the impacts of soil acidification, nutrient deficiencies and heavy-metal toxicity; however, no extensive review has been published that discusses the effects of liming on oil palm growth and yield. It is not enough to emphasize just soil impacts alone, and a thorough assessment must also be given on crops (oil palm) and soil biodiversity. This review synthesizes current understanding and introduces a holistic approach to provide insights into the far-reaching effects liming has on the biogeochemical properties of tropical soil and oil palm crops.

The Effect of POFA-Gypsum Binary Mixture Replacement on the Performance of Mechanical and Microstructural Properties Enhancements of Clays.

Soft clay is categorized as problematic due to its weak and dispersive properties which requires stabilization. In Malaysia, there is another challenge, the increment of palm oil waste productions to meet the global demand for food oil. These two concerns motivate engineers to develop novel strategies for exploiting palm oil waste in soil stabilization. Utilizing POFA as a soil stabilizing agent is an economical and sustainable option due to that POFA contains high pozzolanic characteristics which make it more suitable and reliable to treat soft soil. This study uses the replacement portion of the soil with stabilizing agents -POFA and Gypsum; aiming to achieve Malaysia green technology goals by the balance of the economic expansion and environmental privilege. However, the aim of this study is to determine the effect of POFA-gypsum binary mixture replacement on the performance of mechanical and microstructural properties en-hancements of clays. Kaolin S300 is the control sample whereas POFA and gypsum are the used binders. The mechanical properties and shear strength with the curing period were tested. Results showed that treated clay marked increment of optimum water contents and reduction of maximum dry densities, a clear 200% of enhancement of treated clay’s compressive and shear strength with curing period as well as the amount of stabilizing agent to less than 15% of POFA and 6% of POFA. It is also found that as gypsum contains a high amount of lime (CaO), the results illustrate that strength raises significantly even with less curing time due to its high reactivity compared to silica and alu-mina. Overall, the results show an enhancement of mechanical and shear strength properties of treated kaolin supported by microstructural SEM imaging.

Eco-friendly gypsum-lime mortar with the incorporation of recycled waste brick

To reduce the consumption of cement and thus mitigate the negative impact of its manufacturing industry on the environment, the use of traditional gypsum and lime binders, with less environmental impact, was adopted in this work for the preparation of an eco-friendly mortar. Furthermore, recycled waste brick was incorporated as a replacement for sand to promote the recycling of construction and demolition waste on one side, and to reduce the depletion of natural sand resources on the other side.In this paper, the effect of the amount of lime, gypsum, and brick powder on the mortar properties was investigated. To this end, eight mortars were prepared using gypsum, lime, and gypsum-lime binders with and without brick powder. The replacement percentage of sand by brick powder in the gypsum-lime mortars was 33% and 66%. A cement mortar was also included for comparison purposes. It was observed that increasing the percentage of gypsum in gypsum-lime mortars improves bond, flexural, and dry compressive strengths but results in more porous structure and less resistance in the saturated state. Although the replacement of 66% of sand by the brick powder in mortars containing 66% of gypsum as binder increased the capillary absorption rate, it provided less dense mortars with a much better bond strength than cement mortar. It also improved the mechanical strength and especially the saturated strength compared to the mortar without brick powder addition. This improvement can be attributed to the formation of new CASH/CSH phases. The mortar containing 66% of gypsum as binder and 66% of brick powder as aggregate can be a very promising alternative towards an ecological mortar with less impact on the environment.

Compressed unfired blocks made with iron ore tailings and slag

Growing demand for houses in urban India has increased the requirements for construction materials such as clay fired bricks and cement blocks. At the same time, conventional practice of brick manufacturing is not environment friendly due to high energy consumption and CO2 emissions during various stages of its production. Therefore, recent trend in research has been directed towards utilization of various industrial wastes and methods, which emerge as sustainable alternatives for environmental concerns arising in the construction industry. This study focused on utilizing mining waste, namely iron ore tailing (IOT) in development of stable blocks. It has reported various properties of compressed unfired blocks formed by IOT and ground granulated blast furnace slag (GGBS) in varying proportions and with a fixed amount of lime. The combination of GGBS and lime was found to be suitable in stabilizing IOT towards block production. Furthermore, a maximum compressive strength of 7.7 MPa was achieved for blocks after 28 days of air curing. Also, the addition of GGBS has reduced the water absorption and apparent porosity of the IOT blocks, confirming the positive interaction between IOT, GGBS and lime. It also indicates the prospective of blended binders in improving the compactness of the blocks, which will have direct influence on the durability and service life of the blocks. Finally, the results show that most of the developed blocks satisfy the requirement of IS 1077 specification and can be used in various applications such as load and non-load bearing walls, framed structures, foundations and pedestrian walkways.

Effect of Applying Low Rates of Agricultural Lime and Chicken Manure on Selected Soil Properties on &amp;lt;i&amp;gt;Ferralsols&amp;lt;/i&amp;gt; of Lake Victoria Agro-Ecological Zone, Uganda

Ferralsols form a dominant type of soil on which most crops are grown in the Lake Victoria agro-ecological zone. Soil acidity has been recognized among the most important agricultural problems in such soils, which adversely affect crop production and productivity. A study was conducted with the objective of determining the effect of applying low rates of lime and chicken manure on selected soil chemical properties. Using a Split Plot Factorial Randomized Complete Block Design, agricultural lime (0.0, 0.5, 1.0, 1.5 & 2.0 t·ha-1) as the main plot and chicken manure (0.0, 1.0, 2.0 & 3.0 t·ha-1) as sub-plot were applied, replicated three times. The test crop was common bean var. NABE 15. The experiment was conducted for three rainy seasons, two seasons on-station and one season on-farm on Ferralsol soil in the Lake Victoria crescent of central Uganda. The results showed that applying low rates of lime with chicken manure significantly (p 2 = 0.987) relationship with pH change was obtained when 0.5 t·ha-1 lime was applied with the four chicken manure rates in Mukono. From the study, we recommend the application of small quantities of lime at 1.0 t·ha-1 with either 2.0 or 3.0 t·ha-1 chicken manure.

The production of protective earth-based mortars for earth constructions in southeastern Brazil during the 19th century coffee economy

ABSTRACT The study of materials used in ancient buildings provides a means to shed light on traditional building practices of past societies, but can serve as inspiration to tackle challenges faced by the current generation. Characterising earth-based structures and finishing elements is part of this mission, especially at a time when earthen architecture is the subject of renewed interest due to its many advantages, particularly in terms of sustainability. This paper considers a set of historical earthen houses built during the first phase of the coffee economy (1820-1880) in the middle Paraíba do Sul River valley, in southeastern Brazil. Physical (colour and texture) and chemical (FTIR, TGA, XRF, and XRD) analyses performed on a large set of mortar and local soil samples collected in the region formed the basis for discussing possible soil selection criteria as raw materials, texture solutions, and the stabilisation strategy of the final product. This last aspect implied the addition of small quantities of lime, in the case of external renders and more sporadically in plasters, without the use of fibres or organic additives. Chemical data and historical sources suggest that the raw materials used for this purpose were probably brought to the region from coastal areas.