Carbonation Resistance of Sustainable Concrete Using Recycled Aggregate and Supplementary Cementitious Materials

Green concrete is a recent sustainable practice in UAE that was enforced by Dubai Municipality in construction field within the emirate of Dubai to reduce the carbon foot print in construction industry and to increase the durability of the structures. This led the construction industry to reduce the usage of ordinary portland cement by replacing it with supplementary cementitious materials (SCMs) such as Grand Granulated Blast Furnace Slag (GGBS) and flyash (FA). Incorporating GGBS or FA in concrete mixtures can improve durability parameters of hardened concrete, such as resistance to water permeability, reduced water absorption and chloride penetration. This ultimately increases the structure’s service life by increasing the threshold of concrete mixture for chloride induced corrosion. On the other hand, carbonation induced corrosion to concrete is usually being ignored or forgotten generally, due its usual slow rate ingression in plain portland cement concrete mixtures. Several studies showed that incorporating some types of SCM – especially at high percentage - can reduce the concrete resistance to carbonation. Additionally and for concrete with recycled aggregate, carbonation investigation should be taken into consideration. This is since recycled aggregates are reused aggregates that are extracted from demolished structures and buildings which were already subjected to different environmental exposures and deteriorations. Unlike chloride penetration, there is no direct ASTM standard test to anticipate the concrete mixture resistance to carbonation at early ages. In this study, concrete mixtures with flyash and different recycled aggregate replacement percentages are investigated for carbonation resistance in accelerated proposed method, considering concrete mixtures’ key parameters like water-cement ratio, and total cement content. The results are analyzed to arrive to pertinent conclusions for the best utilization of sustainable concrete for carbonation resistance.

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The Potentials of Iron and Steel Slags as Supplementary Cementitious Materials in the Nigerian Construction Industry: A Review

Nigerian Journal of Environmental Sciences and Technology - March 2018 ◽

10.36263/nijest.2018.02.0092 ◽

2018 ◽

Vol 2 (2) ◽

pp. 208-218

Author(s):

O. R. Ogirigbo ◽

J. O. Ukpata ◽

I. Inerhunwa

Keyword(s):

Portland Cement ◽

Construction Industry ◽

Waste Product ◽

Steel Production ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Partial Replacement ◽

Iron And Steel ◽

Tropical Environments ◽

Iron And Steel Production

Ground Granulated Blast Furnace Slag (GGBS) is a type of Supplementary Cementitious Material (SCM) that is currently being used extensively in the global construction industry. SCMs are cheaper than Portland cement, help to improve certain properties of concrete and also help to reduce the environmental footprint associated with the production of Portland cement. GGBS is readily available in most parts of the world as a waste product from iron and steel production. However, its use as a SCM in some countries has not been fully maximized. This is primarily because of lack of documented studies on the properties of GGBS that influences its suitability as a SCM, especially in tropical environments. This paper reviewed the use of GGBS as a SCM for the partial replacement of Portland cement, with particular emphasis on its potential use in tropical warm environments such as Nigeria and other similar countries.

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Durability of clinker reduced shotcrete: Ca2+ leaching, sintering, carbonation and chloride penetration

Materials and Structures ◽

10.1617/s11527-021-01644-7 ◽

2021 ◽

Vol 54 (2) ◽

Author(s):

Marlene Sakoparnig ◽

Isabel Galan ◽

Florian R. Steindl ◽

Wolfgang Kusterle ◽

Joachim Juhart ◽

...

Keyword(s):

Binding Capacity ◽

Cementitious Materials ◽

Chloride Penetration ◽

Supplementary Cementitious Materials ◽

Conventional Concrete ◽

Sprayed Concrete ◽

Carbonation Resistance ◽

Negative Environmental Impact ◽

The Impact ◽

Positive Effect

AbstractThe reduction of clinker use is mandatory to lower the negative environmental impact of concrete. In shotcrete mixes, similarly to the case of conventional concrete, the use of supplementary cementitious materials (SCMs) and proper mix design allow for the substitution of clinker without compromising the mechanical properties. However, the impact of the substitution on the durability of shotcrete needs to be further assessed and understood. The results from the present study, obtained from real-scale sprayed concrete applications, show a reduction of the Ca2+ leaching and sintering potential of clinker-reduced shotcrete mixes due to the presence of SCMs. This positive effect, crucial for low maintenance costs of tunnels, is mainly related to a reduced portlandite content, which on the other hand negatively affects the carbonation resistance of shotcrete. Additionally, the hydration of SCMs positively influences the chloride penetration resistance presumably due to a combination of microstructural changes and changes in the chloride binding capacity. Differences found in the pore size distribution of the various mixes have low impact on the determined durability parameters, in particular compared to the effect of inhomogeneities produced during shotcrete application.

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Long-term performance of sustainable pavements using ternary blended concrete with recycled aggregates

10.21079/11681/40780 ◽

2021 ◽

Author(s):

Gilson Lomboy ◽

Douglas Cleary ◽

Seth Wagner ◽

Yusef Mehta ◽

Danielle Kennedy ◽

...

Keyword(s):

Portland Cement ◽

Cementitious Materials ◽

Recycled Concrete ◽

Supplementary Cementitious Materials ◽

Recycled Aggregates ◽

Concrete Aggregate ◽

Portland Cement Concrete ◽

Cement Concrete ◽

Concrete Aggregates ◽

Concrete Mixtures

Dwindling supplies of natural concrete aggregates, the cost of landfilling construction waste, and interest in sustainable design have increased the demand for recycled concrete aggregates (RCA) in new portland cement concrete mixtures. RCA repurposes waste material to provide useful ingredients for new construction applications. However, RCA can reduce the performance of the concrete. This study investigated the effectiveness of ternary blended binders, mixtures containing portland cement and two different supplementary cementitious materials, at mitigating performance losses of concrete mixtures with RCA materials. Concrete mixtures with different ternary binder combinations were batched with four recycled concrete aggregate materials. For the materials used, the study found that a blend of portland cement, Class C fly ash, and blast furnace slag produced the highest strength of ternary binder. At 50% replacement of virgin aggregates and ternary blended binder, some specimens showed comparable mechanical performance to a control mix of only portland cement as a binder and no RCA substitution. This study demonstrates that even at 50% RCA replacement, using the appropriate ternary binder can create a concrete mixture that performs similarly to a plain portland cement concrete without RCA, with the added benefit of being environmentally beneficial.

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Development and Guidance of Green Concrete for Leed™ Applications

Journal of Green Building ◽

10.3992/jgb.5.4.111 ◽

2010 ◽

Vol 5 (4) ◽

pp. 111-120

Author(s):

John T Kevern

Keyword(s):

Green Building ◽

Cementitious Materials ◽

Recycled Concrete ◽

Supplementary Cementitious Materials ◽

Recycled Aggregate ◽

Strength Development ◽

Concrete Aggregate ◽

Total Contribution ◽

Recycled Materials ◽

Concrete Mixtures

As green building rating systems such as LEED™ become more popular, the use of recycled materials in construction is increasing. Concrete can be produced with significant quantities of supplementary cementitious materials or recycled aggregate materials. However, modifying concrete mixture proportions for improved recycled content credits also impacts strength and long-term durability. Without properly understanding the effects recycled materials have on concrete, greener concrete can be less desirable from a lifecycle perspective from poor durability. This research investigates the impacts different types and quantities of supplementary cementitious materials and recycled concrete aggregate have on strength development and concrete durability, specifically deicer scaling. Improvements to deicer scaling resistance were investigated using a novel soybean oil sealer. The concrete mixtures were also evaluated within the LEED™ recycled materials criteria for selection based on economy and total contribution value. Considerations are included to assist designers in the selection of greener concrete mixtures for appropriate applications.

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Fresh and Mechanical Properties of Sustainable Concrete Using Recycled Aggregates

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.803.239 ◽

2019 ◽

Vol 803 ◽

pp. 239-245

Author(s):

Ahmad Khartabil ◽

Samer Al Martini

Keyword(s):

Construction Industry ◽

United Arab Emirates ◽

Construction Projects ◽

Rapid Development ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Abu Dhabi ◽

Natural Aggregates

In the last few decades, the United Arab Emirates (UAE) witnessed rapid development in the construction industry. It was recently emphasized to adopt sustainability practice in all aspects related to construction. The recent sustainable practice that was enforced by Dubai Municipality in construction field is “greening the concrete” by solely replacing the Portland Cement with supplementary cementitious materials (SCMs), such as grand granulated blast furnace slag (GGBS) and fly ash. On the other hand, the use of recycled aggregates can also contribute to the greening of concrete and to the reduction of carbon foot print from the construction industry in the UAE. Consequently, it is significant to study the suitability of local available recycled aggregate and their effect on concrete fresh and hardened properties, in order to expand the current practice. The recycled aggregates, used in this investigation, are obtained from a local recycled aggregates plant in Abu Dhabi using concrete from demolished buildings in Abu Dhabi. The natural aggregates in concrete mixtures were replaced by recycled aggregates with the following percentages: 20%, 40%, 60% and 100%. The concrete parameters investigated are mainly the slump retention, rheology and compressive strength. The results are analyzed to arrive to pertinent conclusions for the utilization of concrete with recycled aggregates in different types of construction projects.

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Utilization of Waste Polysilicon Sludge in Concrete

Materials ◽

10.3390/ma13010251 ◽

2020 ◽

Vol 13 (1) ◽

pp. 251 ◽

Cited By ~ 1

Author(s):

Abdul Qudoos ◽

In Kyu Jeon ◽

Seong Soo Kim ◽

Jeong Bae Lee ◽

Hong Gi Kim

Keyword(s):

Construction Industry ◽

Cementitious Materials ◽

Chloride Penetration ◽

Supplementary Cementitious Materials ◽

Fresh Properties ◽

Environmental Threats ◽

Environmental Threat ◽

Granulated Blast Furnace Slag ◽

Carbon Dioxide Co2 ◽

Furnace Slag

Increasing use of cement in the construction industry is causing an alarming increase in carbon dioxide (CO2) emissions, which is a serious environmental threat, it can be reduced by the addition of supplementary cementitious materials (SCMs). The commonly used SCMs like ground granulated blast furnace slag (GGBS), metakaolin (MK) and fly ash (FA) have been successfully used to replace the cement partially or completely. Polysilicon sludge obtained from the photovoltaic industry is also a type of waste material that can be used as SCM because it has high content of reactive SiO2. This study investigates the effects of replacing cement with polysilicon sludge in concrete. Different concrete specimens were made by replacing varying proportions of cement with polysilicon sludge and their properties, such as, fresh properties, compressive strength, heat release, chloride penetration, freeze/thaw resistance and microstructural investigations were determined. The results demonstrate that the polysilicon sludge can be used effectively to replace cement, and environmental threats associated with its disposal can be reduced.

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Variation of Durability and Strength Parameters of Pumice Based Mixtures

Materials ◽

10.3390/ma14133674 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3674

Author(s):

Petr Lehner ◽

Petr Konečný ◽

Pratanu Ghosh

Keyword(s):

Diffusion Coefficient ◽

Portland Cement ◽

Mean Squared Error ◽

High Performance Concrete ◽

Limit State ◽

Cementitious Materials ◽

Time Dependent ◽

Supplementary Cementitious Materials ◽

Ultimate Limit State ◽

Concrete Mixtures

The numerical modelling of chloride penetration into concrete is very sensitive to the correct description of the input data. In the recent era, high-performance concrete (HPC), which combines Portland cement and other supplementary cementitious materials, has been gaining attraction due to their desirable material properties and durability. The presented results show the application of the modified approach for the evaluation of the suitability of the time-dependent model for the variation of the diffusion coefficient. The 26 various binary and ternary-based concrete mixtures blended with volcanic pumice pozzolan (VPP) as a major supplementary cementitious material (SCM) are compared with the reference Ordinary Portland Cement mixture. Other SCMs namely fly ash, slag, silica fume, and metakaolin were also utilized in ternary-based concrete mixtures. In-depth statistical analysis was carried out to show the variability and effects of the amount of the volcanic pumice as an SCM on the diffusion coefficient. The mean value and regression via linear approximation of the time-dependent coefficient of variation of the diffusion coefficients were used as well as the Root of Mean Squared Error approach. The presented results are suitable as the component of the input parameters for the durability-related probabilistic assessment of the reinforced concrete structures exposed to chlorides. In addition, the time-dependent ultimate limit state-related data was presented.

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Concretes with binary mixtures of artificial pozzolans and concrete demolition waste

Ambiente Construído ◽

10.1590/s1678-86212020000400466 ◽

2020 ◽

Vol 20 (4) ◽

pp. 177-188

Author(s):

Cristian Jonathan Franco de Lima ◽

Francisco Roger Carneiro Ribeiro ◽

Geraldo Cechella Isaia ◽

Mauricio Mancio

Keyword(s):

Binary Mixtures ◽

Modulus Of Elasticity ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Demolition Waste ◽

Durability Test ◽

Concrete Mixtures ◽

Pozzolanic Materials

Abstract The objective of this study is to analyse the use of binary mixtures of pozzolanic materials and concrete demolition waste in concrete mixtures, especially the resulting mechanical properties and durability. A total of ten concrete formulations were produced distinguishing them in different types using different Portland cements, different artificial pozzolans and coarse aggregates from concrete demolition. The particular properties of each formulation were verified by testing the axial compressive strength, longitudinal modulus of elasticity and penetration of chloride under immersion. Substitutions were of 15% w.t. and 30% w.t. natural coarse aggregate substituted with concrete demolition waste and, in the case of binary mixtures, additional 25% w.t. of the binder agglomerate substituted with rice husk ash or fly ash. Results showed that the final strength to axial compression and modulus of elasticity of concrete mixtures were negatively affected by utilising demolition waste, but this effect was balanced by adding supplementary cementitious materials. Regarding the durability test, it was found that the lowest coefficients occurred in the mixtures using CP V-ARI, together with artificial pozzolans, in mixtures with 15% w.t. substitution of natural aggregate with recycled aggregate. It was concluded that using recycled aggregates in concrete is viable but conditioned to the concomitant use of pozzolanic materials.

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Evaluation of strength of concrete on different initial exposure condition

Current Materials Science ◽

10.2174/2666145413999201224112446 ◽

2020 ◽

Vol 13 ◽

Author(s):

Sri Ram Krishna Mishra ◽

Pradeep Kumar Ghosh ◽

Manoj Kulshreshtha

Keyword(s):

Portland Cement ◽

High Strength ◽

Cementitious Materials ◽

General Purpose ◽

Supplementary Cementitious Materials ◽

Exposure Condition ◽

Portland Cement Concrete ◽

Initial Exposure ◽

Skilled Manpower ◽

Standard Practices

Background: The previous studies have focused curing effect of mainly on high strength concrete, where strict supervision is maintained. This study is based upon general purpose concreting work for commercial and residential construction in absence of skilled manpower and supervision. Objective: The objective of this study is to establish a thumb rule to provide 7 days initial curing for maintaining quality for unsupervised concreting irrelevant to type of cement and grading. Methods: In this study concrete samples made with locally available commercial cements were cured for various initial exposure. Results: The results shows that concrete cured after a gap of 4 days from the time of de-moulding have given lowest strength as compared to concrete cured in standard practices i.e. where proper curing protocol had been followed. Conclusion: Initial curing is most important aspect of gaining desired strength. The findings after this study shows that curing affects the strength of concrete in variable grading. Initial curing has great importance for concrete with all types of Portland cement. Concrete with supplementary cementitious materials gives lowest strength initially but results higher strength after 28 days as compared to Portland cement.

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