scholarly journals Usage of supplementary cementitious materials: advantages and limitations

2020 ◽  
Vol 142 (1) ◽  
pp. 371-393 ◽  
Author(s):  
Barbara Pacewska ◽  
Iwona Wilińska
Keyword(s):  
Isothermal Calorimetry ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Cement Production ◽  
Degree Of Reaction ◽  
History Of ◽  
The Subject ◽  
Hydrated Products ◽  
Negative Environmental Impact ◽  
Reaction Degree

Abstract It is well known that cement production is not neutral for natural environment among others due to high CO2 emission. Different strategies of mitigation of negative environmental impact of its production are developed. One of the ways is utilization of supplementary cementitious materials (SCMs) in the manufacture of cement and concrete. Introduction of aluminosilicate SCMs into binding mixture makes that more amount of so-called C–A–S–H phase appears in hydration products, affecting microstructure and properties of final hardened composite. The aim of this work is to discuss the possibilities of utilization of selected SCMs in different binding mixtures including some advantages and limitations. Literature review on the subject was carried out. Some of our own research results were also presented. In the Part I of this review, some information about history of ancient binding materials and the possibilities of inspiring modern engineers with ancient constructions in the aspect of using SCMs in modern concrete were presented. Using pozzolanic aluminosilicate SCMs in relation to their influence on formed products, microstructure and mechanical properties of hardened material were discussed. Some problems with possibilities of study of SCMs reaction degree were identified. Emphasis was put on the usefulness of isothermal calorimetry and thermal analysis for investigations of hydration process and identification of hydrated products as well as evaluation of degree of reaction of SCMs.

scholarly journals Special Issue: Supplementary Cementitious Materials in Concrete, Part I

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2291
Author(s):  
Alessandro P. Fantilli ◽  
Daria Jóźwiak-Niedźwiedzka
Keyword(s):  
Environmental Impact ◽  
Portland Cement ◽  
Building Materials ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Special Issue ◽  
Cement Production ◽  
Concrete Part

The environmental impact of the Portland cement production and the large use of cement-based building materials is a growing problem [...]

scholarly journals Mechanically activated mine tailings for use as supplementary cementitious materials

2021 ◽  
Vol 6 ◽  
pp. 61-69
Author(s):  
Sivakumar Ramanathan ◽  
Priyadarshini Perumal ◽  
Mirja Illikainen ◽  
Prannoy Suraneni
Keyword(s):  
Mine Tailings ◽  
Isothermal Calorimetry ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Strong Correlations ◽  
Negative Effects ◽  
Cement Pastes ◽  
Amorphous Content ◽  
Milling Duration ◽  
Median Particle

Two mine tailings are evaluated for their potential as supplementary cementitious materials. The mine tailings were milled using two different methods – ball milling for 30 minutes and disc milling for durations ranging from 1 to 15 minutes. The modified R3 test was carried out on the mine tailings to quantify their reactivity. The reactivity of the disc milled tailings is greater than those of the ball milled tailings. Strong correlations are obtained between milling duration, median particle size, amorphous content, dissolved aluminum and silicon, and reactivity of the mine tailings. The milling energy results in an increase in the fineness and the amorphous content, which do not appreciably increase beyond a disc milling duration of 8 minutes. The reactivity increases significantly beyond a certain threshold fineness and amorphous content. Cementitious pastes were prepared at 30% supplementary cementitious materials replacement level at a water-to-cementitious materials ratio of 0.40. No negative effects of the mine tailings were observed at early ages in cement pastes based on isothermal calorimetry and thermogravimetric analysis, demonstrating the potential for these materials to be used as supplementary cementitious materials.

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

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.

scholarly journals Influence of Milling Techniques on the Performance of Wheat Straw Ash in Cement Composites

2020 ◽  
Vol 10 (10) ◽  
pp. 3511
Author(s):  
Abdul Qudoos ◽  
Ehsanullah Kakar ◽  
Atta ur Rehman ◽  
In Kyu Jeon ◽  
Hong Gi Kim
Keyword(s):  
Particle Size ◽  
Wheat Straw ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Hydration Reaction ◽  
Cement Composites ◽  
Cement Production ◽  
X Ray ◽  
Worldwide Production ◽  
Straw Ash

The worldwide production of cement is growing every year due to its increased use in the construction. Cement production is affiliated with an environmental concern as it contributes to the CO2 emissions. It is imperative to reduce the cement production by incorporating supplementary cementitious materials in the cement composites. In this research study, wheat straw ash (WSA) was used as an alternate of ordinary Portland cement. The ash was ground separately with a ball mill and a disintegrator mill as well as with a combination of both to enhance its pozzolanic efficiency. Mortar and paste specimens were made by substituting cement with WSA (20% by weight). Ash specimens were examined in terms of particle size distribution, X-ray diffraction, and X-ray fluorescence analyses. The performance of the ash specimens in cement composites was examined via compressive and flexural strengths, and ultrasonic pulse velocity (UPV) tests. Isothermal calorimetric, thermogravimetric analyses (TGA), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) were also employed on the specimens. The results revealed that the particle size of the wheat straw ash specimens significantly reduced and specific surface area enhanced when ground with a combination of both milling techniques. Cement composites made with this type of ash demonstrated improved mechanical and physical properties, accelerated hydration reaction at the early ages, reduce calcium hydroxide content at the later ages, and densified microstructure.

scholarly journals Production of Ultra-High-Performance Concrete with Low Energy Consumption and Carbon Footprint Using Supplementary Cementitious Materials Instead of Silica Fume: A Review

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8291
Author(s):  
Mays A. Hamad ◽  
Mohammed Nasr ◽  
Ali Shubbar ◽  
Zainab Al-Khafaji ◽  
Zainab Al Masoodi ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Cement Production ◽  
Granulated Blast Furnace Slag ◽  
The Impact

The increase in cement production as a result of growing demand in the construction sector means an increase in energy consumption and CO2 emissions. These emissions are estimated at 7% of the global production of CO2. Ultra-high-performance concrete (UHPC) has excellent mechanical and durability characteristics. Nevertheless, it is costly and affects the environment due to its high amount of cement, which may reach 800–1000 kg/m3. In order to reduce the cement content, silica fume (SF) was utilized as a partial alternative to cement in the production of UHPC. Nevertheless, SF is very expensive. Therefore, the researchers investigated the use of supplementary cementitious materials cheaper than SF. Very limited review investigates addressed the impact of such materials on different properties of UHPC in comparison to that of SF. Thus, this study aims to summarize the effectiveness of using some common supplementary cementitious materials, including fly ashes (FA), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ashes (RHA) in the manufacturing of UHPC, and comparing the performance of each material with that of SF. The comparison among these substances was also discussed. It has been found that RHA is considered a successful alternative to SF to produce UHPC with similar or even higher properties than SF. Moreover, FA, GGBS and MK can be utilized in combination with SF (as a partial substitute of SF) as a result of having less pozzolanic activity than SF.

scholarly journals The Influence of Chemical Activators on the Hydration Behavior and Technical Properties of Calcium Sulfoaluminate Cements Blended with Ground Granulated Blast Furnace Slags

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 268
Author(s):  
Milena Marroccoli ◽  
Antonio Telesca
Keyword(s):  
Blast Furnace ◽  
Co2 Emissions ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
X Ray Diffraction ◽  
Cement Production ◽  
Blended Cements ◽  
Calcium Sulfoaluminate ◽  
Technical Performance ◽  
Technical Properties

The manufacture of Ordinary Portland cement (OPC) generates around 8% of the global CO2 emissions related to human activities. The last 20 years have seen considerable efforts in the research and development of methods to lower the carbon footprint associated with cement production. Specific focus has been on limiting the use of OPC and employing alternative binders, such as calcium sulfoaluminate (CSA) cements, namely special hydraulic binders obtained from non-Portland clinkers. CSA cements could be considered a valuable OPC alternative thanks to their distinctive composition and technical performance and the reduced environmental impact of their manufacturing process. To additionally reduce CO2 emissions, CSA cements can also be blended with supplementary cementitious materials. This paper investigates the influence of two separately added chemical activators (NaOH or Na2CO3) on the technical properties and hydration behavior of four CSA blended cements obtained by adding to a plain CSA cement two different ground granulated blast furnace slags. Differential thermal-thermogravimetric, X-ray diffraction and mercury intrusion porosimetry analyses were done, along with shrinkage/expansion and compressive strength measurements.

scholarly journals Exploring Structural Evolution of Portland Cement Blended with Supplementary Cementitious Materials in Seawater

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1210
Author(s):  
Solmoi Park ◽  
Jun Kil Park ◽  
Namkon Lee ◽  
Min Ook Kim
Keyword(s):  
Portland Cement ◽  
Tap Water ◽  
Structural Evolution ◽  
Extended Period ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Main Reaction ◽  
Strength Development ◽  
Main Reaction Product ◽  
Reaction Degree

The present study investigated the structural evolution of Portland cement (PC) incorporating supplementary cementitious materials (SCMs) exposed to seawater. The samples were made with replacing Portland cement with 10 mass-% silica fume, metakaolin or glass powder. The reaction degree of SCMs estimated by the portlandite consumption shows that metakaolin has the highest reaction degree, thus metakaolin-blended PC exhibits the highest strength. The control exposed to seawater exhibited 14.82% and 12.14% higher compressive strengths compared to those cured in tap water at 7 and 28 days. The samples incorporating metakaolin showed the highest compressive strength of 76.60 MPa at 90 days tap water curing and this was 17% higher than that of the control. Exposure to seawater is found to retard the rate of hydration in all SCM-incorporating systems, while the strength development of the neat PC system is enhanced. The main reaction product that forms during exposure to seawater is Cl-AFm and brucite, while it is predicted by the thermodynamic modelling that a significant amount of M-S-H, calcite and hydrotalcite is to form at an extended period of exposure time.

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