scholarly journals Utilization of microwave-accelerated heating and dewatering in low-pressure conditions to accelerated-cure Type-I cement paste for early-age compressive strength development

2019 ◽  
Vol 26 ◽  
pp. 100920
Author(s):  
Natt Makul
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Low Pressure ◽  
Strength Development ◽  
Early Age ◽  
Type I ◽  
Compressive Strength Development

Early Age Properties of Alkali Activated Brown Coal Fly Ash Binders

2014 ◽  
Vol 931-932 ◽  
pp. 457-462 ◽  
Author(s):  
Chandani Tennakoon ◽  
Kwesi Sagoe-Crentsil ◽  
Jay G. Sanjayan ◽  
Ahmad Shayan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Brown Coal ◽  
Coal Fly Ash ◽  
Coal Ash ◽  
Strength Development ◽  
Early Age ◽  
Compressive Strength Development ◽  
Strength And Durability ◽  
Reaction Processes

The present study evaluates potential re-use options for two different types of brown coal fly ash (class C) sourced from Australia as feedstock for geopolymer binder systems. The study covers analysis of fundamental material and mix-design requirements for geopolymer binders as a basis to achieve durable brown coal ash geopolymer matrices. The study established that reference unblended 100% brown coal ash geopolymer mortar samples yielded low strength, typically below 5MPa and poor durability. However, appropriate blends of brown coal ash with selected black coal fly ash (class F) and blast furnace slag to achieve target Si/Al ratios significantly enhanced both setting characteristics, as well as early age compressive strength development (25-35MPa) while improving overall durability performance compared to reference mixes. Moreover, lagoon fly ash blended geopolymer shows better durability while dry precipitator fails to perform well. The discussion also focuses on key source material parameters and reaction processes that influence compressive strength and durability behaviour of marginal brown coal ash sources during geopolymerisation reactions.

Effects of Different Lithium Admixtures on Ordinary Portland Cement Paste Properties

2014 ◽  
Vol 919-921 ◽  
pp. 1780-1789 ◽  
Author(s):  
Yu Hai Deng ◽  
Chang Qing Zhang ◽  
Hai Qiang Shao ◽  
Han Wu ◽  
Nie Qiang Xie
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Lithium Carbonate ◽  
Lithium Hydroxide ◽  
Strength Development ◽  
Lithium Nitrate ◽  
Cement Pastes ◽  
Compressive Strength Development ◽  
Paste Properties

Lithium-based chemicals are known to their signal effect on restraining alkali-silica reaction but uncertain influence on workability and mechanical property in the concrete. The aim of this research is to analyze the effects of three lithium additiveslithium nitrate (LiNO3), lithium hydroxide (LiOH) and lithium carbonate (Li2CO3) at various dosages, with an extensive comparison on fluidities, setting times and compressive strength of cement pastes. The experimental study shows that test results vary with the type of admixture. In general, three conclusions can be made: 1) lithium nitrate and lithium hydroxide can enhance the fluidity of cement paste, but lithium carbonate has opposite effects; 2) all three lithium salts shorten setting time as well as decrease the strength at suitable dosages; 3) the variations in lithium additives dosages have different influence on the cement pastes setting time and compressive strength development.

scholarly journals The potential use of pumice in mine backfill

2020 ◽  
Vol 1 ◽  
Author(s):  
Mohammed A. Hefni
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Mining Industry ◽  
Strength Development ◽  
Natural Pozzolan ◽  
Mine Backfill ◽  
Natural Pozzolans ◽  
Cemented Backfill ◽  
Compressive Strength Development ◽  
Potential Use

Abstract The use of natural pozzolans in concrete applications is gaining more attention because of the associated environmental, economic, and technical benefits. In this study, reference cemented mine backfill samples were prepared using Portland cement, and experimental samples were prepared by partially replacing Portland cement with 10 or 20 wt.% fly ash as a byproduct (artificial) pozzolan or pumice as a natural pozzolan. Samples were cured for 7, 14, and 28 days to investigate uniaxial compressive strength development. Backfill samples containing 10 wt.% pumice had almost a similar compressive strength as reference samples. There is strong potential for pumice to be used in cemented backfill to minimize costs, improve backfill properties, and promote the sustainability of the mining industry.

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