scholarly journals Investigation of engineering properties of normal and high strength fly ash based geopolymer and alkali-activated slag concrete compared to ordinary Portland cement concrete

2019 ◽  
Vol 196 ◽  
pp. 26-42 ◽  
Author(s):  
Nabeel A. Farhan ◽  
M. Neaz Sheikh ◽  
Muhammad N.S. Hadi
Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2252 ◽  
Author(s):  
Chi-Che Hung ◽  
Yuan-Chieh Wu ◽  
Wei-Ting Lin ◽  
Jiang-Jhy Chang ◽  
Wei-Chung Yeih

In this study, the influence of three mixture variables named Sand/Aggregate ratio, Liquid/Binder ratio, and Paste/Aggregate ratio on the cementitious properties were studied. The durability of cementitious including absorption, absorption rate, resistivity, rapid chloride permeability index, and carbonation rate were examined. Results showed that the alkali-activated slag cementitious has superior durability. The trends of influences on the composites properties for these three mixture variables are similar to those for the ordinary Portland cement concrete. It means that the experiences for making the ordinary Portland cement concrete should be able to be used for the alkali-activated slag cementitious. This paper also provides a lot of data for the alkali-activated slag cementitious for future development of the mix design.


2020 ◽  
Vol 10 (17) ◽  
pp. 6092
Author(s):  
Zhenming Li ◽  
Xingliang Yao ◽  
Yun Chen ◽  
Tianshi Lu ◽  
Guang Ye

Alkali-activated slag and fly ash (AASF) materials are emerging as promising alternatives to conventional Portland cement. Despite the superior mechanical properties of AASF materials, they are known to show large autogenous shrinkage, which hinders the wide application of these eco-friendly materials in infrastructure. To mitigate the autogenous shrinkage of AASF, two innovative autogenous-shrinkage-mitigating admixtures, superabsorbent polymers (SAPs) and metakaolin (MK), are applied in this study. The results show that the incorporation of SAPs and MK significantly mitigates autogenous shrinkage and cracking potential of AASF paste and concrete. Moreover, the AASF concrete with SAPs and MK shows enhanced workability and tensile strength-to-compressive strength ratios. These results indicate that SAPs and MK are promising admixtures to make AASF concrete a high-performance alternative to Portland cement concrete in structural engineering.


2019 ◽  
Vol 803 ◽  
pp. 262-266
Author(s):  
Osama Ahmed Mohamed ◽  
Maadoum M. Mustafa

Alkali activated slag (AAS) offers opportunities to the construction industry as an alternative to ordinary Portland cement (OPC). The production of OPC and its use contributes significantly to release of CO2 into the atmosphere while AAS is an industrial by-product that contributes much less to the environmental footprint that needs to be recycled if not landfilled. This paper outlines some of the key properties, merits and demerits of AAS when used as alternative to OPC. Competitive compressive strength of AAS concrete is amongst of the advantages of replacing cement with AAS while high shrinkage and carbonation levels are potential disadvantages.


2010 ◽  
Vol 168-170 ◽  
pp. 2008-2012 ◽  
Author(s):  
Yong Hao Fang ◽  
Ya Min Gu ◽  
Qiu Boa Kang

The chemical shrinkages of alkali-activated slag cement (AASC), and the effect of fly ash, MgO burnt at 900°C and the curing solutions were studied. The shrinkages were compared with that of ordinary portland cement (OPC). The results show that the chemical shrinkage of AASC is lower than that of OPC. Adding fly ash and light-burnt MgO reduced the early age chemical shrinkage, while the shrinkage-reduction effect decreased with the age. The alkality of the curing solution has significant effect on the hydration and shrinkage of AASC. The chemical shrinkage of AASC increased with the alkali concentration of the curing solution. The mechanisms of fly ash, MgO and curing solution on the shrinkage were discussed.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ganesan Lavanya ◽  
Josephraj Jegan

This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were150×150×150 mm cubes,100×200 mm cylinders, and100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.


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