Percentage Replacement Of Cement Research Articles

Quaternary blended eco high performance concrete utilizing high volumes of siliceous additives

This research examines the optimal feasibility of incorporating siliceous additives as an adjunct material for cement in the formulation of environmentally sustainable high-performance concrete (Eco-HPC). Siliceous materials, including Nano silica (NS), Rice Husk Ash (RHA), and Fly Ash (FA), were fine-tuned within the cementitious system in order to achieve the amplified performance of Eco-HPC by reducing the required cement content from 370 kg/m3 to 273 kg/m3. This is achieved by employing the Modified Andreasen and Andreasen (MA&A) particle packing model, with ‘q’ (distribution factor) as ‘0.3’. The Levenberg Marquardt algorithm (curve fitting) was utilized to validate the packing density of each concrete blends. Initially, the dry NS agglomerates are synthesized into stabilized aqueous dispersion through High shear mixing (10 min/1750 rpm) followed by probe sonication (15 min/(1/3) s/s) with anionic surfactant dosage of 0.1 g/10 g. Incorporating secondary siliceous binders into the cement matrix led to an enhancement in the packing density, increasing from 0.94 (nullary) to 0.96 (quaternary) which in turn alters the reactivity and cohesiveness of the matrix. Compressive strength values for Binary (NS2), Ternary (RN15, FN20), and quaternary mix (FRN25) were observed as 57.42 MPa, 56.83 MPa, 55.34 MPa, and 52.58 MPa, respectively, for primary binder contents of 362 kg/m3, 314 kg/m3, 296 kg/m3, and 273 kg/m3 without compromising durability parameters. An assessment on reduced carbon dioxide emissions indicated that increasing the cement replacement percentages in Eco-HPC by up to 30% for binder contents of 358 kg/m3, 296 kg/m3, 259 kg/m3, and 273 kg/m3 resulted in a reduction of CO2 emissions by 2.98%, 18%, 27%, and 23.33%, respectively. Among the twelve formulated mixes, FRN25, FRN20, FRN15 and FN30 are identified as Eco-HPC mix through a computational framework which integrates the packing density, carbon emission, strength and diffusion coefficient.

Experimental investigation of Bamboo Leaf Ash and Rice Husk Ash as partial replacement cement in concrete

Construction work was mostly done in the ancient era using mudstone obtained from industry. The experimental investigation on the strength properties of M30 grade concrete, in which rice husk ash and bamboo leaf ash have largely substituted cement. One of these waste materials produced as a by-product of the rice paddy milling industry is rice husk ash (RHA). and Bamboo is used as scaffolding for the manufacture of domestic goods and construction paper. In this investigation, concrete specimens created with 0%, 5%, 10%, and 15% of the RHAsh and BLAsh as the cement replacement percentages were used to calculate the strength-related parameters such as compressive strength, splitting tensile strength, and flexural strength. Samples were examined at 7, 14, and 28 days old. Finally, it was determined that, when compared to other replacement levels, the 5% RHAsh and BLAsh replacement level in M30 grade concrete demonstrated to be greater.

Analyzing the Mechanical, Durability, and Microstructural Impact of Partial Cement Replacement with Pumice Powder and Bamboo Leaf Ash in Concrete

This study explores the physiomechanical and durability properties of C-25 concrete by partially replacing cement with blends of pumice powder (PP) and bamboo leaf ash (BLA). The combined amount of major oxides SiO2, Al2O3, and Fe2O3 in PP is 84.59%, while in BLA, it is 74.4%, classifying PP and BLA as class N and F pozzolans. Subsequently, the study examines the impact of different cement replacement percentages, emphasizing 5%, 10%, 15%, and 20% on C-25 with varying mixes of concrete: Mix-1 (100, 0, and 0), Mix-2 (90, 5, and 5), Mix-3 (85, 10, and 5), Mix-4 (85, 5, and 10), and Mix-5 (80, 10, and 10) which correspond to the proportions of OPC, VPP, and BLA used in each mix respectively and by using 1 : 2.34 : 2.68 (cement : sand : aggregate) with the water/cement ratio (w/c) of 0.491. The study’s findings indicate that as the proportion of PP and BLA increases in concrete, the workability of the mixture decreases. Moreover, on the 28th day, Mix-2 with (35.84 MPa) and Mix-3 with (33.55 MPa) met the desired mean compressive strength (33.5 MPa) required for C-25 concrete per the ACI standards. Additionally, the flexural strength of concrete produced with partial replacement of Mix-2 with a flexural strength of 3.86 MPa fulfills the minimum strength requirement of 3.5 MPa specified by the C-25 ACI standards. The PP and BLA blended concrete had lower water absorption than the control mix in Mix-2. It also improved resistance to sulfuric acid attack, and Mix-3 had the least strength reduction of 9.59%. In contrast, the control mix has a 33.34% strength reduction.

Strength and Water Absorption Properties of Cement Bricks Containing Sago Fine Waste

The contamination created by the discharge of sago waste, a by-product of sago milling activities, must be addressed. Using sago waste, specifically sago fine waste (SFW), as a partial cement replacement can be environmentally responsible with a cost-effective choice. The effect of adding sago waste to cement brick characteristics was explored in this study. SFW was utilised to make five brick mixes with partial cement replacement percentages of 0%, 1%, 2%, 3%, 4%, and 5%. The mortar mix has a 1:3 ratio, consistent with Malaysian brick production regulations. All specimens had a water-cement ratio of 0.6 and had been cured for 7, 28, and 56 days for compressive strength tests and density, while water absorption tests were performed on the specimens at cured 28 days. As a result, SFW2 produces the greatest results compared to control bricks, where the compressive strength is 15.8MPa and density is 2157kg/m3 . SFW generally decreased the strength of the brick. However, it was discovered that replacing a maximum of 5% SFW can be used for load-bearing internal wall class 1 because the strength is more than 7 MPa, according to MS 1933: Part 1: 2007. Therefore, This proves the potential of SFW as a new pozzolanic material that can produce more sustainable bricks.

Limestone powder, calcined clay and slag as quaternary blended cement used for green concrete production

Cement is among the most widely used building materials in recent years. In addition, the accumulation of massive waste has impacted the city's appearance. As a result, there was a need to reduce waste by using by-products from industrial waste to replace cement and reduce greenhouse emissions to produce mortar or concrete green that has good performance, environmentally and sustainably. This research study aims to design green concrete with the highest feasible replacement level with different cement content that satisfies fresh and mechanical characteristics used for structural application and eliminate negative environmental impacts simultaneously. The empirical work was conducted by preparing 12 blends to produce green concrete by substituting cement with three ratios of various by 30% (10% LMP +10% SS + 10% CC), 40% (10% LMP +10% SS + 20% CC), and 50%(10% LMP +15% SS + 25% CC) with three binder contents (355 kg/m3, 400 kg/m3, and 460 kg/m3). The mix design was carried out according to the American Concrete Institute (ACI) Code. Then environmental influences of green concrete blends were calculated by evaluating the declines in carbon dioxide (CO2) emissions. The results showed that adding limestone powder (LMP),calcined clay (CC), and steel slag (SS) as partial cement replacement decreased the slump properties of fresh concrete, so an increased dosage of superplasticizer (SP) in the fresh properties is needed. Green concrete containing quaternary cement by 30%, 40%, and 50% with SP dosage certain gave higher compressive, flexural, and splitting strength values at 90 days compared to normal concrete. However, UPV values indicate that all green concrete is of suitable quality. While water absorption has slightly increased in quaternary cement containing 50% for binder content 355, 400, and 460 kg/m3 increased by 4.2%, 2.7%, and 2.1%, respectively, compared with plain concrete. The evaluated reduction of carbon dioxide emissions study indicated that the green concrete, when increased in cement replacement percentages by up to 50% for binder content 355, 400, and 460 kg/m3 reduced CO2 emissions by 35.9%, 36.4%, and 37.1%, respectively. As a result, adopting the idea of green concrete is a promising strategy for reducing carbon dioxide emissions and conserving natural resources.

ENCAPSULATION OF GROUND BOTTOM ASH AS SUPPLEMENTARY CEMENTITIOUS MATERIALS FOR CEMENT MORTAR

Excessive carbon dioxide (CO2) emissions due to the Portland cement manufacturing process have encouraged the industry to look for more sustainable alternatives to cement. Supplementary cementitious material (SCM) has been widely used to improve concrete performance through considerable research. By-product waste, such as fly ash, has been utilized in many construction projects. It is an effective solution to solve long-term environmental pollution. As one of the coal industry by-products, bottom ash has similar chemical properties compared to fly ash, but it is rarely used as SCM because of its size. Therefore, this research aims to modify the regular bottom ash and observe the strength development of cement mortar incorporating bottom ash as SCM. The pre-treatment process of bottom ash was performed by 4 hours of milling to produce micro-size particles. The chemical and physical properties of modified bottom ash were evaluated before being cast into cement mortar specimens. Various percentages of cement replacement using modified bottom ash were used in this research. The evaluations include X-ray fluorescence (XRF) analysis, specific gravity, particle size analysis, scanning electron microscope-energy dispersive X-ray (SEM-EDX), normal consistency, and setting time. The compressive strength and strength activity index were evaluated to obtain the strength development and optimum composition of cement mortar incorporating bottom ash, caused by pozzolanic activity. The results indicate that bottom ash positively affects the strength development of cement mortar, and it can be used as SCM to produce more sustainable cement-based construction materials.

Untreated municipal solid waste incineration ashes for cement replacement

This paper characterised the two different ashes, namely Boiler Ash (BOA) and Residue Ash (RA), collected from Qatar's Municipal Solid Waste Incineration (MSWI) plant through a range of detailed analyses (chemical, physical and morphological). The potential utilisation of these raw MSWI ashes as supplementary cementitious material (SCM) in cement-based composites has been investigated by replacement with 0%, 10%, 20%, and 30% by weight of cement. The effect of the replacement levels on workability, setting time, and strength was investigated. Test results showed that setting time increased and workability decreased with the increase of BOA content. On the contrary, RA substitution decreased the setting time and increased the workability. The highest compressive strength was obtained in RA-incorporated mortars at a 10% replacement ratio. Beyond the 10% replacement ratio, RA incorporation significantly reduced the strength. Due to BOA's high unburned carbon content, BOA substitutions reduced the strength of the mortars. However, the impact of the replacement ratio was not as strong as those in RA mortars. Considering setting time, workability, and compressive strength, BOA and RA's optimum percentage of cement replacement was 20% and 10%, respectively. Heavy metal and salt leaching from MSWI ash-incorporated mortars were evaluated by the monolithic tank test. Results indicated that most toxic metals and salts, except Ba and Cl-, were stabilised in the cement matrix.

A novel integrated approach of RUNge Kutta optimizer and ANN for estimating compressive strength of self-compacting concrete

In this study machine learning models are used that forecast the compressive strength of self-compacting concrete (SCC) depending on percentage replacement of cement by supplementary cementitious material. In order to predict the mechanical property of SCC, a hybrid artificial neural network (ANN) along with metaheuristic optimization techniques and two traditional models were employed which comprised of 300 datasets. Several input factors are employed in the modelling process, including cement, the water-binder ratio, coarse aggregate, fine aggregate, fly ash (FA) and the superplasticizer. ANN hybridised with RUNge Kutta optimizer (RUN) was chosen as one of the top predictive models based on coefficient of determination ((R2 = 0.933 (in training) and R2 = 0.9203 (in testing))) findings and model validation. According to the rank analysis, the ANN-RUN surpassed other models with a score of 128. Permutation feature importance, statistical analysis, and comparisons amongst regression models are used to determine the models' efficacy. The best input parameters were selected based on person correlation and density plot. Also, the use of Taylor diagrams and accuracy matrices was also examined for the visual comprehension of the data which has shown similar results as discussed above. The results show that the suggested machine learning models attained consistent accuracy and can be used as a robust technique to predict the compressive strength of SCC.

Investigating the performance of ternary cementitious systems incorporating wollastonite powder and lime sludge in concrete

The production of cement results in a significant amount of energy consumption and CO2 emissions, which are major contributors to environmental pollution. Researchers have developed a ternary blended mix concrete to address these concerns by partially substituting cement with a combination of lime sludge (LS) and wollastonite powder (WP). This study investigated the mechanical properties (compressive strength, spilt tensile strength, and flexural strength) of a ternary blended concrete mix with a grade of M30. 180 specimens, including 60 cubes, 60 cylinders, and 60 prisms, were prepared for testing. The blended concrete mix was produced using different percentages of cement replacement by LS (5%, 10%, 15%) and WP (10%, 15%, 20%). The compressive strength for the ternary mix at 10% LS and 15% WP was 44.78% higher than the conventional mix, the flexural strength ternary mix at 10% LS and 15% WP was 25.46% higher than the conventional mix, and spilt tensile strength ternary mix at 10% LS, and 15% WP was 27.30% higher than the conventional mix at 28 days and trend is almost same for 7,56 and 90 days . The results showed that a ternary mix containing 75% cement, 10% LS, and 15% WP exhibited the best mechanical properties.

Effect of nano silica on strength and permeability of concrete

Nanomaterials are extremely active in altering the characteristics of cementitious composites at the nano scale due to their nano size. The hydration process, which is proportional to the available surface area, changes the characteristics of cementitious composites more quickly as a result of the larger surface area of these materials. Even a very small percentage of cement replacement can improve concrete strength and permeability. In the present study, of the available nanomaterials (silica fume, nano-silica, nano-alumina, fly ash, etc.), the effect of nano-silica inclusion on the mechanical properties and permeability characteristics of cementitious composites has been examined. Cement replacement is ranging from 0.5 percent to 2.0 percent for a nominal mix of concrete (Grade M20). Experimental works are carried out in accordance with Indian Standards to have an insight into the mechanical and permeability properties of concrete, and to analyze the microstructure of the developed nanocomposites. A total of 105 specimens were cast to test the compressive, tensile, and flexural strength of nano-modified concrete at various ages. The findings of the tests showed that the permeability of concrete reduced with age while its compressive strength greatly improved in the early age. At 1.5 percent, a maximum decrease in permeability was observed, while concrete with 2 percent nano-silica showed a marginal increase in permeability. The aggregation of nanoparticles could be the cause. The influence of the nano-filler and the improved pozzolanic reaction resulted in a more homogeneous and less porous microstructure of the cementitious composites. It is concluded that nano-silica due to its pozzolanic activity additional calcium silicate hydrates are formed, thus imparting higher strength and improved microstructure leading to a low permeable concrete.

Compressive strength studies of concrete with partial replacement of cement and fine aggregate with incinerated solid waste and recycled plastic waste

Solid waste has become a nuisance in the majority of the cities in the country. Many cities have failed to better management of solid waste. The use of solid waste is one of the environment-friendly options available to reduce environmental impact. This research investigates the effect of utilizing Incinerated Solid Waste (ISW) and Recycled Plastic Waste (RPW) as a partial replacement for cement and fine aggregate. The standard tests on cement, fine aggregate and coarse aggregate were conducted. Experimental studies were conducted to use ISW and RPW as a replacement for fine aggregate in varying percentages and ISW as a replacement for cement in varying percentages keeping 20% sand replacement by incinerated solid waste constantly. Concrete cubes of sizes 150 × 150 × 150 mm were cast and slump tested. The compressive strength tests for concrete curing ages 7-day and 28-day were determined, respectively. Workability decreased as cement and fine aggregate replacement increased. The experimental investigation concluded that up to 20% of fine aggregate and 15% of cement replacement with ISW rendered better concrete strength. With a higher percentage of cement replacement, the reduction in strength may be attributed to the reduced formation of calcium silicate compounds. The results have shown that blended concrete can reduce environmental degradation attributed to solid waste. Further studies on the chemical analysis of the ingredients and durability of mixes may help fortify the present results.

Experimental behavior of buckling restrained braces by adding diferent admixtures concrete and using the steel core under cyclic loads

The fibers in the concrete cause soft rupture, and the compressive and tensile samples are not ruptured after failure, this is one of the benefits of Steel fibers, especially the sinusoidal and hooked fibers during an earthquake which allows residents to escape. In addition to the positive effect on mechanical properties, steel fibers improve the matrix of concrete, provide ductility and response to impact load, and control crack width and propagation. This study, given that the use of fly ash and micro-silica in addition to improving the durability and performance of concrete is also effective in protecting the environment by replacing cement instead. In the following, preparing samples of the compressive and tensile strength of non-fibrous concrete, and concrete containing steel fibers with 6 different percentages (0.4, 0.6, 0.8, 1, 1.2, 1.5) and composition of Steel fiber and polypropylene in three different compositions (0.3PP + 0.8SF and 0.4PP + 0.4SF and 0.15PP + 1.5SF) were investigated and after achieving the optimal percentage (the percentage with the highest compressive and tensile strength given economic considerations), under the loading protocol SAC/BD 97.02, while extracting seismic parameters and studying curves of hysteresis, energy absorption, the lateral displacement, the effects of the use of these fibers were investigated. In the last step of the research, considering the major properties of pozzolanic materials, adding fly ash and micro-silica to concrete containing steel fibers with the optimum percentage of Steel fibers, by comparing it with concrete containing Steel fibers and non-fiber concrete and determining the appropriate percentage of cement replacement, the effect of the use of fly ash and micro-silica in preventing the buckling of buckling restrained braces was investigated.

Kinetics behavior of delayed ettringite in limestone calcined clay cement (LC3) by thermodynamic approach and consideration of the time factor

In this study, a thermodynamic and kinetics simulation is used to extract the kinetics diagrams of ettringite (as the main product of sulfate attack) to predict the kinetics behavior of limestone calcined clay cement (LC3) with various cement replacement percentages and the ratio of calcined clay to cement replacement (CC/CC + L) during exposing to a 30 g/l Na2so4 solution. The simulation results are compared with experimental and modeling results to the confirmation of present model's accuracy. The comparison of results shows suitable conformity. Kinetics has to be taken into account in addition to thermodynamics in order to evaluate the performance of LC3 cement in a sulfate-rich environment. Analyzing kinetics diagrams shows that a high CC/CC + L ratio leads to a reduction of ettringite formation during sulfate attack, however, CC/CC + L of 0.6 could be considered as the optimal ratio because of better kinetics performance. Also, three kinetics level for ettringite formation is introduced in this study. Increasing two parameters, cement replacement percentage and CC/CC + L ratio, cause the reduction of ettringite formation and also affects the ettringite production rate during the sulfate attack. In LC3 cement, ettringite formation is controlled kinetically in the first level and so, the exertion of initial sudden stress due to the fast formation of ettringite doesn't happen.

Durability of concrete made with groundnut shell ash as cement replacement

Concrete was considered in time past to be very durable, however many structures continue to show signs of deterioration during the specified or traditionally expected service life. The process of deterioration is more often caused by environmental factors. These have continued to enhance further research on processes as well as effective preventive measures on how best the use of available materials continually to produce durable concrete. The objective of this research is to investigating durability of using concrete produced with groundnut shell ash as replacement for cement. Groundnut Shell ash (GSA) was used to replace cement in percentages of 5%, 10%, 15%, 20% and 25% respectively. Sulfuric acid was used to provide the acid environment required for the short time durability test which comprise of 0.0005 %Ammonia (NH3), 0.00001 %Arsenic (As), 0.0002 %Chloride (Cl), 0.0001 %Heavy metals (Pb), 0.0001 %Iron (Fe), 0.00002 %Nitrate (No3), 0.00015 %, Oxygen absorbed (O), 0.0025 %and Non-volatile residue. Concrete Cubes were cast for control and three (3) samples for each for various percentage of cement replacement with 7, 14, 21 and 28 days curing period, a Second batch samples were inserted into sulfuric acid for another 28 days to determine durability of concrete. The results shows a loss in weight of the concrete with increase in curing age while decreases with increase in the dosage of GSA. With treatment, the concrete cube has a lower percentage loss in strength and the lowest value of percentage loss in strength achieved at 10% GSA at 28 days curing in sulfuric acid with a value of 0.18%. The reduction in percentage loss in weight recorded in the treated samples shows that concrete produced with GSA are more durable when compare to natural concrete.

Compressive and Flexural Strength of High-Volume Fly Ash Mortars Aged with Air-entraining Admixtures

This paper presents the findings of an investigation into the compressive and flexural strength of various cement mortars containing very high levels of Class F fly ash (HVFA). A total of twelve cement mortar mixtures with constant water/powder ratios, cement, sand, and Air-Entraining Admixtures (AEA) were subjected to 20, 30, 40, 50, 60, and 70% partial replacement of cement content with Fly Ash (HVFA) class F. The results of the tests show that the compressive and flexural strength decreased slowly as the fly ash content increased to up to 40%, but the strength values began to decrease dramatically with the addition of a higher amount of fly ash. According to the results, the best percentage of cement replacement with fly ash in mortar is 40%. It has 24% less compressive strength and 13% less flexural strength than 20% FA mortar. In general, the air-entraining admixture has no negative effect on the properties of the cement mortars. The measured properties of the hardened mortar are very satisfying.

An Experimental Study on Concrete with Partial Replacement of Cement By Rice Husk Ash and Bagasse Ash

Utilization of waste materials in concrete manufacture provides a satisfactory solution to some of environmental concerns and problems associated with waste management. Agro waste such as rice husk ash and bagasse ash were used as pozzolanic material for development of blended cement. The properties of concrete with partial replacement of cement by rice husk ash and bagasse ash for about 30% were investigated which includes its compressive strength, split tensile, flexural strength, durability property such as acid attack and sulphate attack. Among the various percentage replacement of cement by rice husk ash and bagasse ash, the strength test result shows that the optimum percentage replacement was about 70 : 20 : 10 (Cement : RHA : BA) which gives the optimum proportion of 30% replacement of cement with rice husk ash and bagasse ash to produce high performance concrete and contribute to sustainable construction. The cement in the concrete replaced by Bagasse Ash and Rice Husk Ash by the percentage of 5%, 10%, 15%, 20%, 25% and 30%. This optimum proportion result obtained is beneficial in improving the mechanical strength and durability property of the concrete. In this project work Conplast 340 Superplasticizer was used to improve the workability of concrete with replacement materials.

Application of consistency-based water-to-binder ratio to compensate workability loss in concrete modified with rice husk ash

Rice husk ash is a material that has the potential to replace cement partially. Many research works concluded that besides having some environmental advantages, the use of rice husk ash (RHA) also improves the hardened properties of concrete. This experimental study addresses the effect of the RHA on the basic properties of ordinary Portland cement by evaluating the standard consistency, initial setting time, and final setting time of RHA-added cement. This study also presents the fresh and hardened properties of concrete modified with RHA. The replacement of cement was done with five different percentages (0%, 5%, 10%, 15%, and 20%) of RHA. Samples were also segregated based on the two different methods of the selection of water to binder (w/b) ratio. In the first method w/b ratio was kept constant at 0.45 for all cement replacement percentages (RHA%). In the second method, the w/b ratio was selected based on the standard consistency of the modified cement. The findings of the experimental study show that standard consistency is increased with the increment in RHA%. A small increase in the initial setting time can be noticed with lower RHA% (5% and 10%), however, higher RHA% causes a decrease in the initial setting time. No significant change in the final setting time was found due to the addition of RHA. The workability of the concrete decreases significantly with respect to RHA% in the case of constant w/b ratio samples. But in consistency-based w/b ratio samples, RHA% has an insignificant effect on workability. The compressive strength of concrete increases with the increase in RHA% up to a 10% value for the constant w/b ratio samples. However, an insignificant change was noticed due to RHA% when the consistency-based w/b ratio had been applied. The study concludes that the strength of concrete can be improved by cement replacement with RHA with some sacrifice in terms of workability. But if we add extra water to compensate for the workability loss, we can replace cement with RHA without any significant strength loss.

A Review: The Effect and Behaviour of Concrete Using Lime Stone Powder

Abstract: Concrete is a major worldwide building material, in which Portland cement is the usual binder. Taking into account environmental factors in cement production, especially concerning CO2 emissions and energy consumption, this works aims at the development of concrete with lime powder. M30 grade of concrete is taken for investigation. The cement is replaced by lime of 5%, 10% and 15%.The concrete mix design will be done as per IS10262-2009. The properties are yet to be study including the workability and characteristics of fresh concrete such as slump, compaction factor and strength properties of hardened concrete including Compression strength, Split tensile strength and Flexural strength for various percentage replacement of cement by lime stone powder

Concrete Resistance Achieved with Subtly Ground Tube Glass of Cathode Ray as Supplementary Cementitious Material to Sulphate Attack

One of the essential requirements in modern civil engineering is a sustainable building, with the aim of reducing the harmful impact on the environment. Since the early XXI century, usage of recycled materials has been insisted on, which could, at least partly, substitute traditionally used materials. Although there is no serial manufacturing of TV sets with cathode ray tubes anymore, piles of cathode ray tube glass (CRT) at the waste disposal sites have still been on the increase. This experimental research was supposed to determine the potential for using subtly milled CRT glass as a supplementary cementitious material and to check the resistance of similar concretes to the sulphate action. Six testing concrete batches were made. The percentage of cement replacement percentage with CRT was: 5%, 10%, 15%, 20% and 35%, by mass. Durability assessment of concrete to sulphate action was done by visual estimation of concrete appearance as well as through testing the compressive strength variations of treated concrete specimens 3, 6, 12 and 36 months old. After soaking the specimens in a 5% solution of Na2SO4 for 36 months, concretes with 15% to 20% of replaced cement with finely ground CRT glass have simultaneously satisfactory compressive strength and resistance to sulfate attack. In this sense, this range of replacement of cement with finely ground CRT glass can be recommended for practical application.

Mechanical performance and microstructural properties of cement mortars containing MSWI BA as a minor additional constituent

Along with an increase in the amount of municipal waste being incinerated, the amount of Municipal Solid Waste Incineration Bottom Ash (MSWI BA) is growing every year. Combined with limited landfill sites in the Netherlands, this necessitates new applications for the MSWI BA disposal. The larger MSWI BA fractions (> 3 cm) can be successfully used as a natural aggregate substitute in concrete. At the same time, the fine MSWI BA fraction (< 3 cm) has several drawbacks (high porosity, high contaminant content, metallic aluminum, etc.), which make it difficult to use this way. However, if this fine MSWI BA fraction is subjected to treatment that eliminates these shortcomings, it can become a product suitable as a Minor Additional Constituent (MAC) for cement (< 5 % w/w). The addition of MAC allows to use less cement without having a negative influence on its properties, therefore reducing the carbon footprint, and utilizing suitable waste materials (instead of landfilling them). In this paper, mortars and pastes containing the decontaminated (by sieving out the most contaminated fraction < 125 µm) and mechanically treated MSWI BA < 3 mm was used as a cement replacement in the range of 0–20 %. Three types of milled fines were studies, two of them had a particle-size distribution close to CEMI 42.5 and 52.5 to determine the optimum percentage of cement replacement, while the third was not optimized. Effects of MSWI BA fine replacements were studied in terms of mechanical properties, hydration (isothermal calorimetry), microstructure (optical microscopy), and the environmental impact (the standard leaching test by ICP–AES and ion chromatography). The results showed that the mildly milled fines, with a cement replacement of 1 %, are most suitable as a MAC as they have the lowest environmental impact, and no negative effects on the mechanical properties (compressive strength).