Showing papers on "Cement published in 2019"
TL;DR: In this paper, the authors investigated the influence of binder composition and time interval between layers on layer-interface strength in 3D-printable cement-based compositions (3PCs).
258 citations
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TL;DR: In this paper, a large amount of studies are devoted to seeking synergies between FA, HCFA, granulated blast furnace slag (GBFS), and limestone, focusing on durability characteristics of composites cement containing FA and HCFA.
230 citations
TL;DR: This study proposes a low-carbon, cement-free, clay-based approach for simultaneous S/S of As and Pb in the contaminated soil, and elucidates the chemical interactions between alkali-activated clay binders and potentially toxic elements.
230 citations
TL;DR: In this paper, the potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies, and seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed.
Abstract: The cement industry is facing numerous challenges in the 21st century due to depleting natural fuel resources, shortage of raw materials, exponentially increasing cement demand and climate linked environmental concerns. Every tonne of ordinary Portland cement (OPC) produced releases an equivalent amount of carbon dioxide to the atmosphere. In this regard, cement manufactured from locally available minerals and industrial wastes that can be blended with OPC as substitute, or full replacement with novel clinkers to reduce the energy requirements is strongly desirable. Reduction in energy consumption and carbon emissions during cement manufacturing can be achieved by introducing alternative cements. The potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies. Seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed. The study provides a comprehensive analysis of options for future cements, and an up-to-date summary of the different alternative fuels and binders that can be used in cement production to mitigate carbon dioxide emissions. In addition, the practicalities and benefits of producing the low-cost materials to meet the increasing cement demand are discussed.
174 citations
TL;DR: In this paper, the authors developed an innovative and cleaner method for stabilization/solidification (S/S) of municipal solid waste incinerator fly ash (IFA) by the incorporation of supplementary cementitious materials (SCMs) and green stabilizers.
167 citations
TL;DR: In this article, the mechanical properties of fly ash silica-fume plain concrete (FA-SPC) and fly ash-silicafume coconut fibre reinforced concrete (SCFRC) are investigated.
164 citations
TL;DR: In this article, two types of recycled cements (RC-450°C and RC-800‚C) were produced in order to reduce the CO2 emission for cement production.
163 citations
163 citations
TL;DR: In this paper, nano-SiO2 (NS) was introduced in a steam-cured cementitious system to induce the early hydration, with intention to promote the early strength.
150 citations
TL;DR: Experiments demonstrated that Si-modified MgO cement can transform dredged sediment into fill materials with satisfactory mechanical properties and contaminant immobilisation, and the synergy between reactive MgOs and Si-rich industrial waste is a novel option for sustainable remediation and environmental applications.
145 citations
TL;DR: In this article, the effect of different percentages of crumb rubber as a partial substitution of both; fine, and coarse aggregates by volume percentage (0, 10, 20 and 30%) on the hardened properties (compressive, tensile and flexural strength) and impact resistance of slag based geopolymer concrete (replacing the cement by; ground granulated blast furnace slag (GGBFS) activated with sodium silicate and sodium hydroxide).
TL;DR: In this paper, the feasibility of using marble powder in a better way with the use of supplementary cementitious materials was examined, where sand was partially replaced with marble powder up to 15%.
TL;DR: In this article, the effects of foam content as well as fly ash and silica fume inclusion on some physical and mechanical properties of foam concrete, subjected to various curing regimes, were researched.
TL;DR: In this paper, the authors compared the engineering properties of normal strength and high strength FAGP and AAS concrete with OPC concrete and found that the tensile strength of both concrete types was comparable to OPC when the compressive strength of the concrete was about 35'MPa (normal strength concrete).
TL;DR: In this article, the authors reviewed the sustainability aspects for steel and cement industries, as both are highly demanding and carbon dioxide emissions from the steel industry can be reduced effectively by carbon sequestration methods.
TL;DR: In this article, a silane polymer emulsion treatment method was used to promote the strength of pervious concrete while maintaining its permeability, and the results revealed that silane treatment significantly improved the strength while maintaining acceptable permeability due to the redistribution of the cement paste.
TL;DR: In this paper, the authors investigated the utilization of metakaolin as a mineral admixture in improving the properties of concrete mixes, containing varying percentages of recycled coarse aggregates (RCA).
TL;DR: In this article, the effect of the chemical composition of the amorphous and crystalline phases of fly ash on the compressive strength of a fly ash cement mortar was studied.
TL;DR: In this article, the authors presented data on the chloride diffusion coefficient (Dcl), ageing coefficient (m) and chloride threshold (Clth) related to seven concrete mixes (four M35 and three M50) with OPC, OPC+PFA (pulverised fuel ash) and limestone-calcined clay cement (LC3).
TL;DR: In this article, the effects of the GO content and water/cement ratio on the mechanical properties and microstructure of GO-cement composites were systematically investigated through experimental tests.
TL;DR: In this paper, the C-A-S-H composition, morphology and density are characterized for Limestone Calcined Clay Cement (LC3-50) blends containing clays with various kaolinite contents.
TL;DR: In this article, a new mixing technique, in which a small amount of fly ash was mixed with cement, slag and water and allowed to react for a period of time before an aggregate and residual fly ash were added, was proposed.
TL;DR: In this article, the effects of pre-curing and carbonation duration on compressive strength and microstructure characteristics of Portland cement paste were investigated, and it was shown that 30-40% water loss of cement paste is ideal for CO2 uptake.
Abstract: This study aims to investigate the effects of pre-curing and carbonation duration on compressive strength and microstructure characteristics of Portland cement paste. Experimental results showed that 30–40% water loss of cement paste is ideal for CO2 uptake. The combination of appropriate pre-curing and carbonation duration could increase compressive strength of cement mortar effectively, especially at early age. The optimal pre-curing duration decreases as the carbonation duration increases. Thermogravimetric analysis indicated that carbonation could retard hydration of cement paste and higher concentration of CO2 increases crystallinity of carbonate. According to MIP results, the influence of hydration and carbonation on pore structure of cement paste is different. Carbonation could decrease large capillary porosity obviously while hydration fills small capillary first. In addition, it is observed from EDS point analysis that excessive carbonation lead to decalcification of C-S-H. Therefore, suitable pre-curing and carbonation duration is of significance to improve the strength and microstructure of cement pastes.
TL;DR: In this paper, the authors used CEM I with two w/c ratios (0.45 and 0.60) to characterize the possible altered zone and to identify the mechanisms of degradation under such conditions.
TL;DR: In this article, the authors explored the mechanical and rheological properties of cement reinforced with graphene oxide (GO, STANDARD GRAPHENE INC.) in the presence of a superplasticizer.
Abstract: We explored the mechanical and the rheological properties of cement reinforced with graphene oxide (GO, STANDARD GRAPHENE INC.) in the presence of a superplasticizer. The GO enhanced the compressive and flexural strengths of the cement matrix by 40% and 70%, respectively, at extremely low GO concentrations (
TL;DR: Findings from the study show that finer biochar particles offer superior performance in improving early strength and water tightness compared to normal biochar (with macro-pores), while 28-day properties are similar for mortar with both GBC and NBC respectively.
TL;DR: In this article, an experimental study on the effect of fly ash fineness on the heat of hydration, microstructure, flow and compressive strength of blended cement pastes was carried out and evaluated against control cement paste.
TL;DR: In this article, the authors investigated the rheological properties of the geopolymer grout in comparison with the cement-based grouts included fly ash and cold bonded fly ash at various dosage rates and water/binder ratios (0.75-1.5).
TL;DR: In this paper, the sulfate resistances of sustainable concrete incorporating various solid waste materials, including waste glass powder (WGP), coal gangue powder (CGP), and fly ash (FA), were investigated.
TL;DR: In this article, the effect of nano-silica particles on the hydration, the rheology and the strength development of cement pastes is evaluated by means of isothermal calorimetry and thermogravimetric analysis.
Abstract: The aim of the present work is to evaluate the effect of nano-silica (NS) on the hydration, the rheology and the strength development of cement pastes. The advance of chemical reactions is monitored by mean of isothermal calorimetry and thermogravimetric analysis: adding nano-silica particles speeds up the hydration of the cement paste but alter its workability. Indeed, the effect of the nano-silica particles on the hydration kinetics can be modelled by accounting for its high specific surface and a flocculation model based on the DLVO theory is proposed so as to investigate the stability of nano-silica suspensions in the fresh cement paste. As a consequence, the dosage of nano-silica can be optimized to promote the early age strength. Lastly, a ternary blend incorporating fly ash can be designed so as to provide an early age strength similar to that of the cement while lowering the induced CO 2 emissions.