Cement Waste Research Articles

Influence of using agro-waste as a partial replacement in cement on the compressive strength of concrete – A statistical approach

Recent efforts in sustainable infrastructure development have focused on using industrial wastes to enhance the mechanical properties of concrete. A majority of the relevant research has aimed at using industrial wastes as a replacement material in cement. Hence, in this study relatively new agro-industrial wastes, namely spent bleach earth (SBE) and de-oiled Earth (DOE), were used in combination with rice husk ash (RHA) as substitute in cement. Cement was partly replaced with different percentages of SBE, DOE, and RHA, individually and in combination, to form binary and ternary blended binders. The percentage of waste in cement was varied from 0% to 20% in increments of 2.5%. The ratio of fine to coarse aggregate was maintained constant at 40:60 for the concrete mixtures. The results indicated the partial replacement of cement by 5% SBE, 7.5% DOE and 7.5% RHA individually increased the compressive strength of concrete. A furture increase in the replacement percentage resulted in gradual decrease in the compressive strength. Furthermore, the combined influence of the aforementioned pozzolanic wastes was examined by using ternary blends comprising concrete SBE and DOE; concrete SBE and RHA; as well as concrete DOE and RHA. The relation between the compressive strength at 7 and 28 days for different levels of replacements indicated that the compressive strength increased when a 2.5% concentration of the aforementioned three combinations was added to cement. Prediction analysis was conducted using the regression and artificial neural network (ANN) methods. The R2 values obtained with the regression and ANN methods were 0.6561 and 0.9673 for 7 days and 0.6441 & 0.9636 for 28 days respectively.

The Potential Use of Waste Cement as a Filler in Polymer Composites

This study explores the potential to use waste cement particles from ready-mixed concrete industry as a low cost filler in polypropylene. Its effects on mechanical and morphological properties were investigated in comparison with commercial cement and calcium carbonate. Mixing and shaping procedures of the polymer composites specimen were conducted by two-roll mill and injection molding, respectively. Next, the effect of filler loading (0, 10, 20, 30, 40, and 50 phr) and filler type on the mechanical and morphological properties of the polymer composites were studied. The results show that when filler loadings increased, the young’s modulus, flexural modulus, impact strength, and hardness of the polymer composites also increased accordingly, while the tensile strength and flexural strength decreased. Moreover, the results show that the waste cement had a greater effect on the enhanced mechanical properties compared to commercial cement and calcium carbonate. Furthermore, the polymer composites’ morphology was studied using scanning electron microscopy. A microstructure analysis was performed to verify and provide a better assessment of the performance properties of the polymer composites.

A comparison of the acid mine drainage (AMD) neutralization potential of low grade nickel laterite and other alkaline-generating materials

Acid mine drainage (AMD) is a serious environmental problem caused by the weathering of sulfur-rich minerals found in mine sites, typically pyrite. Passive treatment methods have been extensively studied exploring various materials and treatment systems. Limestone is typically used as neutralizing media through open channels or anoxic limestone drains. However, the armouring that occurs when heavy metals precipitate on the surface restricts the lifespan of limestone treatment systems to 15-20 years. Goethite has been characterized to be a good adsorbent of heavy metals found in wastewater. It is abundant in a layer of nickel laterite deposit which are considered mine wastes due to the low amount of nickel present. This study investigates the performance of locally available nickel laterite ore rock, limestone, fly ash, and cement waste as media for AMD neutralization. The treatment efficiency are evaluated based on the physiochemical properties of the AMD, namely: pH, redox potential (ORP), conductivity, total dissolved solids (TDS), and dissolved oxygen (DO).

Active demonstration of the thermal treatment of surrogate sludge and surrogate drums using the GeoMelt™ In Container Vitrification (ICV) melter installed in NNL Central Laboratory

Under the auspices of the THERAMIN project, the GeoMelt™ in-container vitrification (ICV) melter system installed in the National Nuclear Laboratory (NNL) Central Laboratory at Sellafield, UK, has been used to demonstrate the immobilisation of two surrogate feeds. The streams selected for demonstration were a cementitious stream representative of legacy drums or failing cemented wastes packages and a wet waste stream made up of a surrogate for Magnox storage pond sludge and clinoptilolite, an ion exchange material, as a way of demonstrating co-immobilisation. The distribution of waste species throughout the vitrified block were assessed to determine the efficacy of the mixing during the thermal treatment process. Analysis of samples from the off-gas system was carried out to establish an activity balance across the process. This paper will outline the process set up, provide operational data from the melt concluding with an assessment of the applicability of the trials results to thermal treatment of these and similar waste streams.

Influence of a Chromium-rich Industrial Waste on the Hydration and Hardening Processes of Portland Cements with Slag and Limestone Additions

This research work assesses the influence of a chromium-rich waste (from potassium dichromate manufacture) on the hydration and hardening processes of two types of Portland cements with limestone filler and slag additions. Therefore, mixtures of Portland cement and chromium-rich waste, corresponding to 0.5% wt. and 1% wt. Cr, were prepared and tested. The analyses performed on cement pastes with chromium waste content, showed that chromium immobilization is mainly due to the formation of Ca6Al2Cr3O18�32H2O (CrEt); this compound results by the substitution of [SO4]2- groups from ettringite lattice of with [CrO4]2-. CrEt crystals growth on the surface of clinker particles forms a diffusion barrier which explains longer setting times for cements with chromium content. The increase of chromium content in the studied systems decreases the compressive strength values but these remain above the lower limits imposed for this type of materials. The chromium content in leachates prepared according to the method described in SR EN 12457-2, was well below the legal limit of 70 mg/Kg established by Romanian legislation. A better chromium immobilisation was achieved in the cement with slag content, in good correlation with the nature and amount of formed hydrates.

Immobilization of hazardous municipal solid waste incineration fly ash by novel alternative binders derived from cementitious waste

This work aims to immobilize hazardous municipal solid waste incineration fly ash (IFA) using alternative binders recycled from cementitious waste (CW) that was dehydrated. The dehydration temperature of CW applied was 200 °C, 500 °C and 800 °C, and the resulted binder was labelled as DCW2, DCW5 and DCW8, respectively.Thermal treatment increased the rehydration capacity of DCWs. Higher temperatures at 500 °C) can increase the amount of dehydrated phases, and contribute to a higher 28-day strength of DCW pastes. The DCW5 paste had the highest 28-day strength which was 18.74 MPa. The dicalcium silicate phase can be formed in DCW8, which resulted in its slow strength development and a lower 28-day strength compared to the DCW5 paste (about 50 % lower). Chloride contained in IFA can take part in the DCW hydration and contribute to the strength development of the binder-IFA pastes.The use of DCWs as binders had better immobilization efficiency of Pb compared to OPC. Furthermore, the CO2 emission for preparing DCW2, DCW5, and DCW8 was 94 %, 86 % and 65 % lower than that of OPC, respectively. The DCWs can be considered as alternative binders regarding the recycling and immobilization of IFA.

Strength and ultrasonic properties of cemented waste rock backfill considering confining pressure, dosage and particle size effects

It is of great significance to study the material properties of cemented waste rock backfill (CWRB) for preventing mining damages, solving environmental problems and ensuring engineering security. Consequently, this paper carried out the comprehensively factorial tests to investigate the effects of the confining pressure, dosage of cementitious material and particle size distribution (PSD) of aggregate particles on the strength and ultrasonic properties of CWRB, for which the PSD of aggregate particles obeyed Talbot gradation theory. The results show that the relations between the confining pressure and dosage of cementitious material and the compressive strength and ultrasonic pulse velocity (UPV) of CWRB present the positively linear functions. However, the relations between the PSD of aggregate particles and the UPV, compressive strength, cohesive force and internal friction angle of CWRB perform the quadratic functions. It is considered that there is an optimal PSD of aggregate particles in the CWRB for characterizing its optimum material properties, and using the gradation Talbot index for describing that optimal PSD is between 0.4 and 0.6. The microstructure characteristics show that the CWRB with finer PSD of aggregate particles produces more distributions of microvoids and microcracks, while the CWRB with coarser PSD of aggregate particles contains coarser microvoids and microcracks that cannot be completely filled by hydration products and secondary hydration products. However, the dense hydration products can be formed among the particles in the CWRB with a suitable PSD of aggregate particles to reduce these defects. Its mechanism is considered that the superior PSD of aggregate particles can improve the microstructure of CWRB including the scale and distribution of defects, thereby resulting in the improvements of its strength and ultrasonic properties.

Effect of soda-lime glass powder on alkali-activated binders: Rheology, strength and microstructure characterization

Alkali-activated binders (AABs) have the potential to consume various types of cementitious waste materials, including coal ashes, municipal solid waste incinerator ash, palm-oil fuel ash, steel slags, mine tailings, cement kiln dust, ceramic tile residue, rice husk ash, and waste glass. This paper presents a study of alkali-activated cement paste produced with the substitution of the cementitious waste material soda-lime glass, which makes up the major proportion of the general glass waste stream. In the alkali-activated cement paste, crushed soda-lime glass powder (CG) was used as a replacement for class F fly ash (FA) from 0 to 30% by total solid weight, keeping the ground granulated blast furnace slag (GGBFS) content constant at 50%. The influence of activator molarity (4–8 M), alkaline liquid/solid binder (L/S) ratio (0.4–0.5) and different curing conditions (ambient air curing, wet curing, and short-term heat curing) on the rheology, strength, and microstructure of CG-substituted AABs was investigated and optimum conditions are suggested. According to the experimental results, both the workability and strength (compressive and tensile) of the AAB gradually increased with increasing level of substitution of FA by CG. Significant improvement in flow and setting time was seen with the addition of CG, even in mixtures with a low L/S ratio of 0.4. Both ambient and wet curing had more influence on the strength gain of AABs, especially after 28 days. Short-term heat curing resulted in high early strength gain. The dissolution of CG increased with increasing molarity (from 4 to 8 M) of the alkaline solution, which improved both strength and microstructure with curing time. Morphological and elemental analysis indicated an improvement of the microstructure of AABs due to the increased formation of calcium-dominant hydration products and hence reduced porosity with the substitution of CG. However, undissolved large-sized CG particles agglomerated in the binder without participating in the alkaline reactions. These agglomerated particles may induce micro-cracks due to weak bonding between the cement matrix and the smooth CG interface, which reduces the durability of AABs. Therefore, the inclusion of waste soda-lime glass powder with a mean diameter of 10–15 µm as a precursor in FA/GGBFS-based AAB as a replacement for FA is feasible and provides a good solution for waste material recycling.

Recycling brick building waste as a filler on laston AC – WC

Light brick and brick building waste is often found in the demolition of building construction in the form of building wreckage. This chunk can be considered as a substitute for materials in asphalt concrete mixture. The research objectives of light brick and brick building waste can meet specifications to be used as filler material in AC-WC Laston mixes as to which composition, filler levels, and what is the laston mixture of AC-WC which uses a building block filler. This research was conducted based on experiments with a combination of two fillers, namely building waste filler and cement filler, where the variation is. 100% cement filler, 0% building waste cement, 75% cement : 25% building waste, 50% cement : 50% building waste, 25% : 75% building waste, 100% building waste. This research was conducted based on an experiment with a combination of two fillers, namely building waste filler where the variation is.100% research cement filler, 0% building waste, 75% cement: 25% building waste, 50% cement : 50%. Building waste, 25% cement: 75% building waste, 100% building waste the results of testing the marshall characteristics can be concluded that the mixture of AC-WC laston using a variety of filler cement with the waste of light brick building and brick can be used.

Investigation of cold bonded lightweight aggregates produced with incineration sewage sludge ash (ISSA) and cementitious waste

Abstract In order to integrally recycle urban solid wastes as secondary resource materials, cold bonded lightweight aggregates (CBLAs) comprising 100% wt. solid wastes, including incineration sewage sludge ash (ISSA) and concrete slurry waste (CSW), were produced. This study focused on assessing the feasibility of using ISSA in CBLAs and its improvement on thermal stability; studying the influence of CSW as an alternative binder instead of ordinary Portland cement (OPC); quantifying the benefits of using CO2 curing compared to steam curing; and evaluating the addition of waste wood fine (WF) on the properties of CBLAs. The experimental results showed that the combined use of ISSA and CSW to produce CBLAs resulted in better properties than the one produced with ISSA and OPC; and increasing the CSW content had positive influence on the pellet strength. CO2 curing could help to achieve rapid strength development and lower water absorption of the pellets compared to steam curing. The use of WF increased the porosity of CBLAs, resulting in lower bulk densities and higher water absorption values. In comparison, the CBLAs prepared with ISSA had good thermal stability, and showed more than 30% residual strength after exposure to 800 °C. Additionally, the CO2 cured CBLAs can sequestrate 3.9–7.6% per unit wt. of CO2 during the curing process.

Spectroscopic and first-principles investigations of iodine species incorporation into ettringite: Implications for iodine migration in cement waste forms

Low-level radioactive wastes are commonly immobilized in cementitious materials, where cement-based material can incorporate radionuclides into their crystal structure. Specifically, ettringite (Ca6Al2(OH)12(SO4)3∙26H2O) is known to stabilize anionic species, which is appealing for waste streams with radioactive iodine (129I) that persists as iodide (I–) and iodate (IO3–) in the cementitious nuclear waste repository. However, the structural information and immobilization mechanisms of iodine species in ettringite remain unclear. The present results suggested minimal I– incorporation into ettringite (0.05 %), whereas IO3– exhibited a high affinity for ettringite via anion substitution for SO42– (96 %). The combined iodine K-edge extended X-ray absorption fine structure (EXAFS) spectra and first-principles calculations using density functional theory (DFT) suggested that IO3– was stabilized in ettringite by hydrogen bonding and electrostatic forces. Substituting IO3– for SO42– was energetically favorable by –0.41 eV, whereas unfavorable substitution energy of 4.21 eV was observed for I– substitution. Moreover, the bonding charge density analysis of the substituted IO3– and I– anions into the ettringite structure revealed the interaction between intercalated ions with the structural water molecules. These results provided valuable insight into the long-term stabilization of anionic iodine species and their migration in cementitious nuclear waste repository or alkaline environments.

Research and preparation of waste cement slurry as concrete admixture

The application of waste cement slurry as concrete admixture was studied. The chemical constituents, the particle size distribution and concrete test of waste cement slurry were investigated. The results show that the addition of a suitable amount of WS-1 will not have a great impact on the strength of concrete, while improving the workability of the concrete. According to the paper, WS-1 can be used as a admixture to adjust the workability of concrete.

Laboratory production of calcium sulfoaluminate cements with high industrial waste content

A drawback of conventional calcium sulfoaluminate (CS̄A) cement production is the use of the costly raw material bauxite as a source of alumina to form the main clinker phase ye'elimite. Replacement of bauxite with industrial wastes can benefit CS̄A cements economically and environmentally. This study demonstrates the use of high amounts of red mud, a sulfate-rich/high-lime fly ash, and desulfogypsum as raw materials in producing CS̄A clinkers and cements with better mechanical performances than an all-natural raw material CS̄A reference cement. Mineralogical compositions of the clinkers and hydrated cement pastes were investigated using x-ray diffraction, isothermal calorimetry, thermogravimetric analysis and scanning electron microscopy. Compressive strength development of mortars, made with citric acid, were studied up to 28 d. It was found that increasing fly ash increases the belitic nature, and increasing red mud increases the ferritic nature of the clinkers. Mortars with 28-d strengths exceeding 40 MPa could be made with cements containing ~38% waste and only half the bauxite in the reference. Medium early and ultimate strength mortars could be made with a ~55% waste cement when bauxite was reduced to a quarter of the reference, with small additions of Ca(NO3)2·4H2O or Li2CO3. Desulfogypsum, as a source of sulfates, was more beneficial to strength development than natural gypsum. Ye'elimite reactivity was enhanced in red-mud containing cements. Cements with both fly ash and red mud experienced lower carbonation than those made with only one of the two wastes.

Analytical and numerical prediction of mechanical properties of heterogeneous materials with expansive inclusions: Application to waste cementation

In this paper, we are concerned with the analytical and numerical study of the effective properties of heterogeneous microstructures resulting from nuclear waste cementation processes. In certain cases, the presence of free-water in the cement matrix pores causes corrosion of metal inclusions that are immobilized, and which transform progressively into an expansive metal oxide layer. Such expansions may lead to high stress/strain levels able to generate micro-cracks in the cement matrix, and to affect the integrity of the waste containers. A homogenization model is then developed to estimate the effective properties of a composite material including spherical inclusions surrounded by a corrosion product layer seen as an expansive phase. The differential scheme is applied, allowing to extend the model to different types of inclusions with high volume fraction, and an interaction coefficient is introduced that relates macroscopic behavior and expansions at microscale. Finally, numerical 3D simulations are performed to determine the effective properties of representative elementary volumes generated with different shapes and volume fractions of inclusions, some of them exhibiting a layer of expansive phase. A comparison between numerical and analytical results shows a good agreement, which confirms the relevance of the model.

ПОЛУЧЕНИЕ ВЯЖУЩИХ КОМПОЗИЦИЙ ДЛЯ БЕТОНОВ В ЦЕНТРОБЕЖНОЙ ПОМОЛЬНОЙ МЕЛЬНИЦЕ

Abstract. The results of studies on the grinding of waste wet magnetic separation of ferruginous quartz-ites of the Lebedinsky mining and processing plant in a centrifugal grinding unit are given, their grinding features are established. Binder compositions are obtained at different ratios of cement and wet magnetic separation waste in a centrifugal grinding mill at different grinding modes. The features of grinding process-es are studied, the technological and physicomechanical properties of the obtained binding compositions are determined. The data obtained indicate that the use of mineral filler up to 10% provides compaction of the structure due to the presence of fine mineral filler, which will reduce the consumption of Portland cement to 10%. During mechanical activation of the compositions of binding compositions, a sharp increase in the con-centration of surface defects occurs, due to the violation of contacts between crystals with the rupture of sili-con-oxygen valence bonds. The activity of the wet magnetic separation waste of ferruginous quartzites is ap-parently due to the presence of a large number of exchange centers on their surface, a significant part of which are Bronsted acids and bases. The processes of hydration and the formation of cement with the use of binders requires further detailed study.

Radiation exposures from the beneficial use of alumina production residue

ABSTRACTEstimates of radiation exposure are developed over the life cycle of beneficial use in cement of an alumina production residue (APR) waste pile. The life cycle includes radiation exposures that might be experienced by industrial workers involved in excavation and transport of the residue to cement plants, industrial workers at the cement plants, construction workers making use of the cement, members of the public who might be in the proximity of the cement products, and disposal of the cement at the end of its useful life. The results indicate that it is not reasonably likely for exposures related to beneficial use of APR waste in cement to exceed the acceptance criteria delineated in current radiation protection standards for workers and members of the general public.Implications: Radiation exposure estimates developed over the life cycle of beneficial use in cement of an alumina production residue (APR) waste pile indicate that it is not reasonably likely for exposures to exceed the acceptance criteria delineated in current radiation protection standards for workers and the public. Assumed APR waste characteristics, storage, transport, cement production, uses in concrete, and ultimate disposal are generalizable to many APR situations. The findings demonstrate that beneficial use of APR waste as a cement ingredient can be accomplished safely, with potentially significant benefits to management of the large volume of APR being stored around the world.

Mechanical properties and freeze-thaw durability of recycled aggregate pervious concrete

Recycled aggregate (RA) was obtained from waste cement concrete brick with the method of crushing and sieving. In order to research the effect of RA content on the properties of pervious concrete, RA was added to replace natural aggregate with equivalent quality method at different levels (25%, 50%, 75% and 100%). The natural aggregate pervious concrete and RA pervious concrete were prepared in the lab. The porosity, permeability, compressive strength, flexural strength and freeze-thaw (F-T) durability of RA pervious concrete were tested. The results indicated that the compressive strength and flexural strength of RA pervious concrete decreased with the increase of RA content. The rapid decreases for compressive strength and flexural strength occurred when the RA content was 25%-75% and 0%-25%, respectively. The porosity and permeability decreased slowly with the increasing RA content. F-T durability of RA pervious concrete was poorer than the natural aggregate pervious concrete. The incorporation levels had negative effect on the F-T durability, but the compressive strength loss of all groups after 25 F-T cycles met the requirement of the national standard. Although the mechanical properties and F-T durability of RA pervious concrete are not satisfied, it can still be used for sidewalks, parks and other light traffic roads.

Experimental Investigation on Performance of Waste Cement Sludge and Silica Fume-Incorporated Portland Cement Concrete

An experimental investigation on improvisation of the conventional concrete mix by way of incorporating waste by products in view of facilitating partial substitution of concrete ingredients has been reported. The mechanical and durability properties of concrete mix incorporated with waste cement sludge and silica fume were test verified, and the optimal cement replacement proportion was identified. Based on test results, the technical feasibility and performance were assessed. The cement sludge content was partially replaced from 2 to 10% at an increment rate of 2% by weight of cement. The optimum cement sludge content has been identified as 4%. The optimal replacement percentage of silica fume along with 4% cement sludge was experimented up on. The silica fume content was varied from 3 to 12%, yielding dependable and optimal proportions of silica fume at 8% by weight of cement. Relationship between the 28-day compressive and flexural strength was established using an empirical correlation equation.

Green Construction Material: Polyethylene Waste Reinforce Concrete for Panel Application

Plastic Composite Panel (PCP) is an innovation in the field of materials that uses recycling plastic waste to construct composite cement panels. This material innovation is one of the solutionto answer environmental problems caused by plastic waste. Some previous studies mostly used plastic waste for concrete aggregates. Thus, making this study different from previous studies. The purpose of this study is to make a prototype of a PCP that is environmentally friendly with panel dimensions sample of 100 x 30 x 10 mm thick. The method used is an experimental test using materials in the form of polyethylene terephtalate (PET) from used water bottle and cement waste as well as testing its physical and mechanical properties carried out in the laboratory. Variations in PET used for testing materials are 0- 20%. In addition to mechanical properties, specific gravity and porosity test is carried out. The best results shows that 5% PET addition to cement paste increase the flexutral strength to 4.47 MPa compared to control sample which has 3.26 MPa. Porosity test shows that addition of 10% PET reduce the density of PCP to 63.64% compared to control sample that has 44.44%.

LIMBAH TULANG HEWAN SEBAGAI BAHAN PENGGANTI TAMBAHAN CAMPURAN BETON

Concrete is material with satisfy compressive strength, malleable, easily produced, rigid, and economical. This research uses alternative materials in process of mixing concrete environmentally friendly. One alternative used are waste animal bones. The use of this animal bone as a alternative coarse aggregate material for the concrete mixture. This is because the amount of animal bone waste in Indonesia is very much and has not been exploited thoroughly. It can suppress natural damage figures due to wild rock abatting. The purpose of this research is, want to increase the quality of concrete with the added material and animal bones, minimizing the waste of animal bones, creating innovations in the development of environmentally friendly. And the benefits that can be gained from this, for upgrade quality concrete, The latest innovations in the utilization of hard and lightweight animal bone waste are assessed to absorb/substitute coarse aggregate use so that it will affect the weight of concrete, With the use of other added materials such as paddy husk ash and red cement whose characterisiticity almost resembles Portland cement, it can absorb the use of Portland cement in concrete and can be a reference or recommendation for Development in Indonesia that is environmentally friendly. This research uses free variables with the red cement waste brick by 30% & 50% of cement usage, paddy husk ash 20%, and animal bones 15%. In this research, the experimental method was making 4 samples of concrete test objects (15x30) that would be tested in heavy and solid tests at the age of 7.14, and 28 days. From the results of this research in obtaining the weight of concrete using the waste of animal bones is lighter than the weight of normal concrete because of the weight of bone type is much lighter than the rough aggregate in general. The addition of bones in the concrete mixture can reach 89% of the achievement target to produce strong press 35MPa. But the use of pozolan cement can’t be used exceeding 30% of its mixing, because stickiness from pozolan cement not entirely the same as ordinary Portland cement.Keywords: Bones, Concrete Mixture