Experiment research on mix design and early mechanical performance of alkali-activated slag using response surface methodology (RSM)

2016 ◽  
Vol 42 (10) ◽  
pp. 11666-11673 ◽  
Author(s):  
Yuan Gao ◽  
Jinyu Xu ◽  
Xin Luo ◽  
Jingsai Zhu ◽  
Liangxue Nie
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Mechanical Performance ◽  
Mix Design ◽  
Experiment Research ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

scholarly journals Strengthening Behavior of Cemented Paste Backfill Using Alkali-Activated Slag Binders and Bottom Ash Based on the Response Surface Method

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 855
Author(s):  
Qi Sun ◽  
Xueda Wei ◽  
Tianlong Li ◽  
Lu Zhang
Keyword(s):  
Response Surface ◽  
Bottom Ash ◽  
Hydration Product ◽  
Cemented Paste Backfill ◽  
Alkali Activated Slag ◽  
Surface Method ◽  
Optimal Mix ◽  
Paste Backfill ◽  
Activated Slag ◽  
Alkali Activated

A new type of cemented paste backfill (CPB) was prepared by using the bottom ash (BA) from a thermal power plant as an aggregate, alkali-activated slag as a binder, and an air-entraining agent as an admixture. Based on the central composite design (CCD) response surface method, the mix ratio was optimized, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was performed on the optimal mix ratio. ImageJ software was utilized to determine the porosity of the experimental samples at various curing ages. The results indicate that the optimal mix ratio of the aggregate-binder ratio is 3.28, the alkali dosage is 3%, the solid content is 67.44%, and the air-entraining agent dosage is 0.1%. As the curing age increases, the porosity of CPB gradually decreases. A calcium aluminosilicate hydrate (C-A-S-H) gel is the main hydration product of alkali-activated slag. At the beginning of the hydration reaction, the slag gradually dissolves, and the C-A-S-H product binds the BA together. At 14 d, complete calcium hydroxide (CH) crystals appeared in the hydration product. Finally, the degree of C-A-S-H crystallization increased further to form a dense structure.

scholarly journals Investigation of Graphene Derivatives on Electrical Properties of Alkali Activated Slag Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4374
Author(s):  
Wu-Jian Long ◽  
Xuanhan Zhang ◽  
Biqin Dong ◽  
Yuan Fang ◽  
Tao-Hua Ye ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Mechanical Performance ◽  
Structural Defects ◽  
Alkali Activated Slag ◽  
Mechanical And Electrical Properties ◽  
Reduced Graphene ◽  
Graphene Derivatives ◽  
Activated Slag ◽  
Alkali Activated

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.

Experimental investigation of mix design for high-strength alkali-activated slag concrete

2021 ◽  
Vol 291 ◽  
pp. 123387
Author(s):  
Nilvan T. Araújo Júnior ◽  
Victor M.E. Lima ◽  
Sara M. Torres ◽  
Priscilla E.A. Basto ◽  
Antônio A. Melo Neto
Keyword(s):  
Experimental Investigation ◽  
High Strength ◽  
Mix Design ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

scholarly journals The Effect of Reclaimed Asphalt Pavement (RAP) Aggregates on the Reaction, Mechanical Properties and Microstructure of Alkali-Activated Slag

CivilEng ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 794-810
Author(s):  
Juliana O. Costa ◽  
Paulo H. R. Borges ◽  
Flávio A. dos Santos ◽  
Augusto Cesar S. Bezerra ◽  
Johan Blom ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Asphalt Pavement ◽  
Isothermal Calorimetry ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

Reclaimed asphalt pavement (RAP) is a recyclable aggregate produced during the demolition of old flexible pavements and consists of natural aggregates (NA) coated with aged bitumen. The detrimental effect caused by the bitumen coating on strength and porosity has limited the use of RAP on traditional cementitious systems. This study investigates the potential use of fine RAP to substitute NA in the production of alkali-activated slag mortars (AAM). The effect of different activator dosages was assessed, i.e., either 4% or 6% Na2O (wt. slag) combined with a modulus of silica equal to 0, 0.5 and 1.0. The characterisation of 100% RAP-AAM consisted of hydration kinetics (Isothermal Calorimetry), pore size distribution (Mercury Intrusion Porosimetry), mechanical performance (Compressive and Flexural strength), and microstructure analysis (Scanning Electron Microscopy and Confocal Laser Scanning Microscopy). The results show that RAP aggregates do not compromise the reaction of the matrices; however, it causes a significant strength loss (compressive strength of RAP-mortars 54% lower than reference NA-mortar at 28 days). The higher porosity at the interface transition zone of RAP-AAM is the main responsible for the lower strength performance. Increasing silicate dosages improves alkaline activation, but it has little impact on the adhesion between aggregate and bitumen. Despite the poorer mechanical performance, 100% RAP-AAM still yields enough strength to promote this recycled material in engineering applications.

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