Aggregate Replacement Material Research Articles

Study on the cementation and engineering properties of ternary eco-binder mortar containing pulverized coal fly ash mixed with circulating fluidized bed co-fired fly ash

This study aimed to verify the role and feasibility of co-fired fly ash (CFA) as an alternative construction material. It also demonstrated the engineering properties of CFA mortar and compared them with those of pulverized coal fly ash (PCFA) mortar. Further, CFA-PCFA-cement mortar specimens were mixed to produce ternary eco-binder mortars and find the optimal application proportion. The results pointed out that the pozzolanic strength activity index of CFA was 76 %, with only a slight pozzolanic reaction. The sum of the chemical composition (SiO2+Al2O3+Fe2O3) of CFA was insufficient to meet ASTM C618 requirements, and it was deduced that a small amount of CFA should be used as the substitute for cement or fine aggregates. Specimens with CFA replacing fine aggregates contributed to lower water absorption, improved sulfate resistance, and increased compressive strength; Specimens with CFA replacing cement reduced shrinkage and improved sulfate resistance but decreased compressive strength and increased absorption. Blended CFA-cement mortars consisting of 5 % CFA as a replacement material for cement and fine aggregates had excellent engineering properties. Ternary blended CFA-PCFA-cement mortar exhibits superior engineering properties. The optimum proportion is an economy-friendly binder composed of 10 % CFA (5 % as cement and 5 % as fine aggregates) and 10% PCFA (as a replacement for cement).

Development of low carbon concrete and prospective of geopolymer concrete using lightweight coarse aggregate and cement replacement materials

The use of Ground Granulated Blast-furnace Slag (GGBS) as an alternative cement replacement material in combination with conventional coarse aggregate have been successful in the production of near green concrete. Undoubtedly, GGBS has exhibited good cementitious attributes, however, there are concerns with slow strength development and workability owing to its non-pozzolanic activities as well as some degree of porosity notwithstanding the sustainability potential. Therefore, this study presents a lytag based geopolymer lightweight concrete with high strength development, improved mechanical properties and reduced embodied carbon. To further improve and enhance the potential production of green concrete, complete replacement of conventional coarse aggregate with a recycled lightweight aggregate from industrial waste was carried out. The geopolymer precursors consisted of sodium hydroxide, sodium silicate, GGBS and silica fume to optimize the performance of the concrete at 60–80% cement replacement for a target design mix of 20, 30, 40, and 50 MPa. The performance of lytag based geopolymer concrete was compared with that of non-geopolymer lytag based concrete (control samples). The results show a 42% increase in compressive strength for the geopolymer lightweight concrete and a 22% increase in ultimate compressive strain which is an indication of improved moment of resistance in structural design. The results also show a 46–61% reduction in embodied carbon for the use of non-geopolymer lytag based concrete and 69–77% reduction for lytag based geopolymer concrete. The geopolymer concrete between 7 and 63 days of loading increases by 0.55% in creep strain compared with increases of 2.81% for non-geopolymer lytag based concrete and reduction to 27.96% for the normal weight concrete. Modulus of Elasticity reduces with age of loading for the geopolymer concrete during creep at 0.39% compared to reduction of 1.93% for non-geopolymer lytag based concrete and increase of 12% for the normal weight concrete.

Analysis of The Addition Polypropylene Fibre and 8670 Mn Viscocrete added Material on The Split Tensile Strength and Modulus of Elasticity of Concrete

This study used waste coconut fibre and HDPE plastic as partial aggregate replacement materials. Coconut fibre ash has pozzolanic properties, which contain high silicate elements. High-density polyethene (HDPE) plastic has more potent, complex, opaque material properties and is more resistant to high temperatures. Superplasticizer is an admixture added to concrete during mixing and during placing to improve its strength performance. This study aims to study the effect of adding HDPE plastic as a substitute for coarse aggregate, coconut fibre ash as a substitute for fine aggregate and Viscrocrete-8670 MN on absorption, concrete compressive strength and elastic modulus of concrete. With variations in the addition of BN HDPE plastic, 0.5%, 1%, and 1.5%, the coarse aggregate passed 3/8 filter retained by filter no 4, 3% coconut fibre ash for each variation of concrete and Viscrocrete-8670 MN by 0.8% by weight of cement. The maximum value for each concrete test is the absorption value of concrete (4.23% for regular concrete), compressive strength (32.49 MPa for 1.5% HDPE concrete), and the modulus of elasticity (3152 MPa for 1.5% HDPE concrete).

Influence of densified silica fume on engineering properties of concrete containing coal bottom ash aggregate.

Coal bottom ash (CBA) is a significant waste produced by the coal manufacturing power plant, harming the environment. CBA has been used in many studies to replace sand in cementitious materials. However, few studies have investigated the use of CBA in concrete as a sand replacement with densified silica fume (DSF) as a cement replacement. DSF is a potential supplementary cementitious material (SCM) to combat the engineering properties of concrete that are typically decreased when CBA is used as a replacement for natural aggregate. Therefore, the present study aimed to evaluate the influence of DSF on the engineering properties of concrete containing different content of CBA as a partial replacement for natural sand. The mix design of the ordinary Portland cement (OPC) and binary blended concrete comprised 90% OPC and 10% DSF by total binder’s weight. The CBA as the fine aggregate replacement was used at 25%, 50%, 75%, and 100% by total aggregate volume. The mechanical, porosity, absorption performance of DSF and CBA (DSF+CBA) concrete containing CBA as partial aggregate replacement material were investigated. DSF+CBA with 50% CBA replacement showed improved mechanical strength performance than control by 15% at 28d and 5.6% at 56d of curing. However, the total porosity performance for DSF+CBA concrete decrease as CBA content increases. In conclusion, the DSF as SCM in binary blended concrete with CBA content up to 50% achieved a better performance in terms of mechanical properties even though the porosity was marginally increased.

Properties of ultra-high performance concrete and conventional concrete with coal bottom ash as aggregate replacement and nanoadditives: A review

Abstract Ultra-high-performance concrete (UHPC) is a new type of concrete with improved features such as high strength, long service life, ductility, and toughness. UHPC’s energy-intensive cement and quartz sand may make it unsustainable despite its engineering expertise. Thus, a UHPC that is energy efficient and environmentally benign should use less energy-intensive components and industrial wastes. This review consolidates and critically reviews the latest global research on coal bottom ash (CBA) as a fine aggregate replacement material and nano-calcium silicate hydrate (C–S–H) as concrete additives. Based on the critical evaluation, replacing aggregate with CBA up to 60% improves strength by 23%. Since high-quality natural sand is depleting and CBA output is increasing due to coal power plants, the concrete industry can use CBA as an aggregate. However, CBA as an aggregate substitute in UHPC has been scarcely reported. Besides, nanomaterial technologies like nano-C–S–H have also been proven to increase traditional concrete’s strength by 33%. But, their impact on UHPC has yet to be fully explored. Thus, to develop UHPC with a lower carbon footprint and comparable or better performance to market-available UHPC, further research on CBA as aggregate replacement in UHPC with nano-C–S–H as an additive on mechanical durability and microstructure is needed.

Experimental Study on Recycling of Brick Waste in Concrete as Coarse Aggregate

Concrete is made of coarse aggregate, fine aggregate, water, cement in specific mix proportion. Coarse aggregates occupy the largest volume in concrete which is one of the most widely used construction material as per industry surveys. In order to evaluate the feasibility of using brick wastes as coarse aggregate in producing concrete, this study was undertaken. Several million tons of solid waste are produced each year due to construction and demolition activities worldwide, and brick waste is one of the widest wastes. Recently, a growing number of studies have been conducted on using recycling brick waste (RBW) to produce environmentally friendly concrete. The use of brick waste (BW) as potential partial cement or aggregate replacement material is summarized in this review.

Sulfuric acid resistance of concrete containing coal waste as a partial substitute for fine and coarse aggregates

The vulnerability of concrete to sulfuric acid attack requires much attention in both design and maintenance. Taking the waste management approach into account, this study utilized coal waste (CW) as a partial replacement for fine and coarse aggregates. The use of CW as aggregate replacement materials in concrete is a novel topic. Regarding the literature, concrete mixtures with CW aggregates showed relatively similar strength properties to conventional concrete. However, the effects of aggressive environments on the concrete containing CW aggregate have not been addressed. Here, the effects of sulfuric acid attack on the key properties, such as split tensile strength (STS), compressive strength (CS), weight loss, and ultrasonic wave velocity (UWV), were thoroughly assessed. Moreover, scanning electron microscope (SEM) images have been captured to discern the morphology changes. Various CW dosages (0%, 5%, 10%, 15%, and 20% by weight of dry aggregates) were used. The results revealed that higher CW contents led to more water absorption and stiffer mixtures with lower workability. The weight loss of the samples showed an increasing trend with increasing CW contents. The split tensile strength and compressive strength of samples without sulfuric acid attack were enhanced by using 5% and 10% CW. After exposure to the sulfuric acid solution, the strength of CW-concrete samples was continuously decreased by increasing CW contents. The UWV values were decreased by increasing CW contents, which induce more porosity and lower integrity in concrete elements. SEM images show that the use of CW led to the formation of Ca (OH)2 crystals that were not wet, needles of ettringite, and gypsum, which severely hurt the properties of permeability, durability, and strength.

Copper slag and high-strength concrete

In this work, we aim to prepare M30 grade concrete utilizing copper slag as a replacement material for fine aggregates in proportions of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% in the concrete. The experiment was conducted at constant w/b and w/c ratios with varying amounts of superplasticizer, and the performance was investigated based on the workability, mechanical and durability properties of the concrete mixtures. The results indicated that the workability and density of concrete increase significantly with increased copper slag content in concrete mixes. The strength increased with the increase in copper slag until 50% replacement and decreased with a further increase of copper slag content compared to the control mixture. Among the tested proportions, 50% copper slag replacement exhibited high compressive and split tensile strength, sustainable elasticity, and resistivity towards chloride, acid and sulphate attack. Based on the ultrasonic pulse velocity test, the quality of the concrete was identified as excellent, with low porosity and good behaviour. Our study recommends that the industrial waste byproduct copper slag at 50% display improved mechanical properties to achieve improved high-strength concrete (HSC) with good workability and better consistency and would stand as a suitable substitute for sand.

Physical and Mechanical Properties of Cementitious PVC Composites

This research studies the physical and mechanical properties of mortar composed of PVC plastic waste particles used as fine aggregate replacement material. PVC particles in quantities of 5%, 10%, 15%, 20%, 25%, and 30% by volume were used for sand fraction substitution. This quantity of PVC was used to formulate seven mixes with a cement content of 525 kg/m3 and a water-to-cement ratio (w/c) of 0.45. At 7 and 28 days, the compressive and splitting tensile strengths of the mortar's mechanical characteristics were evaluated. Additionally, the physical characteristics of density and absorption were investigated. The findings demonstrated that the mechanical properties and density of mortar containing PVC powder were minimized.

An experimental study on strength characteristics of replacement of fine aggregate with stone dust and coarse aggregate with demolished concrete waste

The report presents a comparative examination of the experimental results of the characteristics of fresh and cured concrete with various natural with recycled coarse and fine aggregate replacement ratios. Crushing leftover concrete from laboratory test cubes and precast concrete columns yielded recycled coarse aggregate. Stone dust was used in place of recycled fine aggregate. One of the most significant components of a reinforced structural part is concrete. Concrete has an inextricable influence on reinforced concrete constructions. Concrete that isn't strong enough puts the entire structure in harm. Many structures nowadays fail as a result of a lack of strength. The mechanical properties of concrete changed by stone dust as a fine aggregate replacement material are investigated in this work. A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse and fine aggregate are presented in the paper. Recycled coarse aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Recycled fine aggregate was replaced by stone dust. Concrete is one of the most important components in reinforced structural member. In reinforced concrete structures concrete have some inseparable influence. Lacking in concrete strength endanger the whole structure. Now a day it is seen that many structures fails due to lack of strength. In this paper investigate experiment is reported on the mechanical properties of concrete modified by stone dust as replacing material of fine aggregate and demolished concrete waste as replacing material of coarse aggregate and a study is conductto determine the engineering properties of compressive strength, tensile strength, flexural strength and water absorption capacity of partially replacement of natural sand and natural aggregate. In recent days the demand of river sand is increasing due to its lesser availability. Hence the practice of partially replacing river sand with stone dust is taking a tremendous growth. Due to critical stage of natural aggregate the availability of demolished concrete as recycled aggregate. Using discarded concrete as recycled aggregate conserves natural aggregate, lowers landfill impact, reduces energy use, and potentially saves money. The materials of the future are recycled aggregate. Stone dust and destroyed concrete waste were used to replace 25 percent, 50 percent, 75 percent, and 100 percent of fine and coarse aggregate, respectively. After a 28-day curing period, concrete samples (cubes, cylinders, and beams) are cast and evaluated. To produce the effect on mortar, several members were built utilising the above percentage. Modified concrete is compared to regular concrete in terms of strength. The strength parameters of concrete employing stone dust as fine aggregate and demolished concrete debris as coarse aggregate are observed to increase in compressive strength, flexural strength, and tensile strength. It was discovered that the concrete may be used as structural members in buildings and other structures.

Investigation on Mechanical and Durability Properties of Concrete Mixed with Silica Fume as Cementitious Material and Coal Bottom Ash as Fine Aggregate Replacement Material

Cement production produces a high amount of carbon dioxide, which has a negative impact on the environment. By utilizing waste products instead of cement, environmental degradation can be reduced. The current study was undertaken to study the mechanical and durability performance of concrete by replacing 7.5%, 10%, and 12.5% silica fume (SF) of cement weight. Additionally, coal bottom ash (CBA) was also substituted as fine aggregates with 10%, 20%, and 30%. Compressive strength and indirect tensile strength were the major parameters regarding mechanical properties, while corrosion analysis and sulfate attack were set for durability performance. Sixteen mixes were prepared including a control mix. Out of these, three mixes contained SF, three mixes contained CBA, and eight mixes contained both SF and CBA with 1:2:4 ratio at 0.5 w/b ratio. The results concluded that the addition of 12.5% SF and 30% CBA gives optimum compressive strength and tensile strength. Furthermore, using the SF and CBA reduces the workability of concrete. Furthermore, the use of these byproducts increased the durability in terms of corrosion and sulfate attack.

Nondestructive Determination of Strength of Concrete Incorporating Industrial Wastes as Partial Replacement for Fine Aggregate.

Schmidt rebound hammer test was employed in this study as a nondestructive test. This test method has been universally utilized due to its non-destructiveness for quick and easy assessment of material strength properties and quality of concrete of an existing structure. Industrial waste materials (air-dried alum sludge, treated alum sludge, limestone dust and quarry dust) were employed as replacement material for fine aggregates in this study. A normal strength concrete was designed to achieve 35 MPa at 28 days, with industrial waste materials replacing fine aggregate at different percentages (0%, 5%, 10% and 15%), and then cured for 7, 28 and 180 days. The compressive strength values and rebound numbers for all the mixes obtained were correlated, and a regression equation was established between compressive strength and Schmidt rebound number. The correlation result showed an excellent relationship between rebound number and compressive strength of concrete produced in this study at all curing ages, with correlation coefficients of R2 = 0.98, R2 = 0.99 and R2 = 0.98. The predicted equation showed a strong relationship with the experimental compressive strength. Therefore, it can be used for the prediction of compressive strength of concrete with industrial waste as a replacement for fine aggregate.

Experimental Investigation on Geopolymer Concrete with Various Sustainable Mineral Ashes.

The aim of this research was to find the best alternative for river sand in concrete. In both geopolymer concrete (GPC) and cement concrete (CC), the fine aggregates are replaced with various sustainable mineral ashes, and mechanical and durability tests are conducted. Specimens for tests were made of M40 grade GPC and CC, with five different soil types as river sand substitute. The materials chosen to replace the river sand are manufactured sand (M-sand), sea sand, copper slag, quarry dust, and limestone sand as 25%, 50%, 75%, and 100%, respectively by weight. GPF50 and CC50 were kept as control mixes for GPC and CC, respectively. The test results of respective concretes are compared with the control mix results. From compressive strength results, M-sand as a fine aggregate had an increase in strength in every replacement level of GPC and CC. Additionally, copper slag is identified with a significant strength reduction in GPC and CC after 25% replacement. Copper slag, quarry dust, and limestone sand in GPC and CC resulted in considerable loss of strength in all replacement levels except for 25% replacement. The cost of GPC and CC is mixed with the selected fine aggregate replacement materials which arrived. Durability and cost analyses are performed for the advisable mixes and control mixes to have a comparison. Durability tests, namely, water absorption and acid tests and water permeability and thermal tests are conducted and discussed. Durability results also indicate a positive signal to mixes with M-sand. The advisable replacement of river sand with each alternative is discussed.

Environment friendly concrete block made from Portland cement and aggregate replacement materials

This research work investigated the properties of concrete block made from Portland cement and aggregate replacement materials. Portland cement (PC) was replaced by fly ash (FA) at 10%, 20%, 30% and sand was replaced by bottom ash (BA) at 10% by weight. Water was used at 7% by weight of total solid mass. Binder : Sand : Stone dust ratio of 1 : 5 : 6, 1 : 4 : 5 and 1 : 3.5 : 4.5 were used. Compressive strength were tested after curing in air for 28 days. The results showed that compressive strength of 1 : 5 : 6 ratio was lower than others. Concrete block replaced PC by fly ash had lower compressive strength when amount of fly ash increased. Concrete block had lower compressive strength when replaced sand by bottom ash. As a result, the mixes with FA as PC replacement and BA as sand replacement at the ratio of 1 : 5 : 6 did not meet the requirement of Thai industrial standard. However, concrete block with PC replaced by fly ash at 10%, 20% and sand replaced by bottom ash at 10% of 1 : 3.5 : 4.5 ratio was higher than 1 : 5 : 6 ratio and this ratio meet the requirement of Thai industrial standard.

Performance evaluation of cellular lightweight concrete using palm oil industrial waste as cement and fine aggregate replacement materials

Cellular lightweight concrete (CLC) or sometimes referred to as foamed concrete is widely used in construction for many decades. The foamed concrete properties include low density, as well as good thermal conductivity, high workability and self-compaction and these characteristics enable foamed concrete in many applications. This research deals with the properties of cellular lightweight concrete (foamed concrete) using wastes of palm oil industries namely, palm oil fuel ash (POFA) of 10% as cement replacement and palm oil clinker (POC) at 50% and 100% as sand replacement to develop 1200 kg/m3 foamed concrete. Six different mixes of foam concrete were prepared and various tests on fresh density, flow table, ultrasonic pulse velocity (UPV), compressive strength, and splitting tensile conducted. The results show that the use of 10% of POFA as cement replacement and 50% of POC sand produced requisite strength for structural grade. For the mix with POC100POFA10, under air curing method, 10.3 MPa was the highest compressive strength was achieved; while, for the mix, POC50 under water curing method, the highest strength of 9 MPa obtained. In a nutshell, the byproduct palm oil industrial waste has a good contributing to the sustainable development of the construction industry as well as the agricultural sector in Malaysia and other oil palm growing countries of the world.

Study of Using of Recycled Brick Waste (RBW) to produce Environmental Friendly Concrete: A Review

Several million tons of solid waste are produced each year as a result of construction and demolition activities around the world, and brick waste is one of the most widely wastes. Recently, there has been growing number in studies that conducted on using of recycling brick waste (RBW) to produce environmentally friendly concrete. The use of brick waste (BW) as potential partial cement or aggregate replacement materials is summarized in this review where the performance is discussed in the form of the mechanical strength and properties that related to durability of concrete. It was found that, because the pozzolanic activity of clay brick powder, it can be utilized as substitute for cement in replacement level up to 10%. Whereas, for natural coarse aggregate, recycled aggregate can be used instead of it, but in limited replacement level. Concrete manufacturing from recycled aggregate can give adequate strength and can be suitable for the producing medium or low strength concrete. On the other side, the utilization of fine recycled brick waste as aggregate in the concrete manufacturing provide development of the properties of concrete and it develops the durability of concrete in some cases when used with replacement level up to 10% by the weight of fine aggregate.

The Performance of Bamboo Fiber as Fine Aggregate Replacement in Concrete

The rapid growth of construction industry has caused a huge demand on natural aggregate as the production of concrete requires massive use of natural stone materials. Due to the increase of demand of this material, it has affected to the shortage of natural aggregate and increased the cost of construction material. On the other hand, bamboo is one of the materials which have a big population and potential to be used in construction due to its durability, flexibility and strength performance. So, bamboo fiber was used as aggregate replacement material to reduce the cost of construction material and pollution as well as to improve the quality of the concrete. The research objectives in this study are to determine the optimum percentage of bamboo fiber as aggregate replacement in concrete and to compare the compressive strength of the bamboo fiber concrete with standard concrete. There were 4 cube specimens casted for each proportion of 0%, 5%, 12.5%, 10%, 12.5%, 15% and 17.5% of bamboo fiber as aggregate replacement in concrete. Then, the compressive strength test was conducted to find the optimum bamboo fiber contents with the maximum workability and strength of the concrete. The findings showed that the replacement of 5% of bamboo fiber achieved the highest strength with 27.77 N/mm2 and the strength decrement difference is only about 2.38% with standard concrete. Based from the result, the 5% bamboo fiber concrete can be suggested as the optimum percentage of bamboo fiber as aggregate replacement in concrete. This study is not only aim in reducing the cost of construction material but it also can be one of the effectives ways to reduce environmental impact by using natural fibers as aggregates replacement.

A review on the effects of artificial light weight aggregate in concrete

The disposal problem of industrial by-products like fly ash, heavy metal sludge, sewage sludge etc. are increasing day by day. To use by-products in large volume the applications like embankment fill or aggregate replacement material should be considered for sustainable development. This study is focused on properties of artificial light weight aggregate on concrete and the effect of cold bonded light weight aggregate on concrete through partial and complete replacement of coarse aggregates. Artificial Lightweight aggregate can be produced by nodulizing the by-product for example fly ash in a pelletizer with a proportionate quantity of water, cement and further hardened by cold bonding or sintering. Due to the impact of earth quake forces all over the world, the need for light weight structural design is increasing presently, as it reduces mass of the structure. The concrete produced is light weight in nature and has added the benefit of reducing overall cost, especially in transportation and placing etc. it has its own advantages like reduced dead load, and thus economic structures, high sound absorption and good fire resistance.
 Keywords—Artificial light weight aggregate, cold bonding, Fly ash, Fly ash aggregate, Pelletization, and Sintering.

Recycling of coal bottom ash (CBA) as cement and aggregate replacement material: a review

The construction sector is a significant contributor to greenhouse gas emissions that contribute to global warming. Therefore, utilizing ‘green and recycled by-products’ in construction is a measure towards a sustainable future. Coal Bottom Ash (CBA) generated from thermal power plants has increases in production. This causes disposal problems. However, due to the ongoing depletion of natural limestone in cement production and aggregate in construction, this material may be used as a recycled construction material. This paper presents a comprehensive analysis of CBA’s physical and chemical properties and the impact on the use of CBA as aggregate or cement. A small volume of CBA can substitute fine aggregates without compromising the strength of the concrete. Further research remains to be carried to explore the potential of this material in producing concrete with enhanced strength.

Extending disposal route of dewatered sewage sludge produced from the new wastewater treatment plant in Nicosia toward sustainable building materials

Due to urban development worldwide, disposing sewage sludge (SS) has become a major concern for many countries. SS produced from the New Waste Water Treatment Plant (NWWTP) in Nicosia has not been used for soil application as it was planned since late 2013 due to absence of legislations regarding this route. This issue has been and still a major concern for of Nicosia Turkish Municipality and its society for many years. This study investigates the potential use of SS as construction material by producing an artificial lightweight aggregate (ALWA) and cement replacement material. Fine dry sludge (FDS) and sewage sludge ash (SSA) were used as raw materials for ALWA production. FDS was incinerated at 850 °C for 1 and 2 h to produce SSA1 and SSA2, respectively. Both SSA1 and SSA2 were mixed separately with FDS in different proportions and incinerated at 1100 °C to produce lightweight aggregate AG1 and AG2, respectively. Potential use of SSA1 and SSA2 as cement replacement materials was assessed by measuring the Pozzolanic activity of both ashes throughout physical and chemical tests. It was found out that increasing amount of FDS reduced specific gravity of AG1 and AG2, while increasing amount SSA in the mix improved the surface texture and increased the specific gravity of both AG1 and AG2. Results also indicated that both SSA1 and SSA2 have Pozzolanic properties based in all tests performed. Therefore, using sewage sludge produced from the NWWTP in Nicosia as a sustainable construction material is potential and this could extend the disposal route of the sludge and resolve the accumulation problem in Nicosia.