## 4 Conclusions  
This study evaluates the effects of MgO, MWCNT, and rGO on the physical characteristics related to the workability (slump flow, flow time, and flow velocity), compressive strength, UPV, and microstructural characteristics of developed AAECs that incorporate binary and ternary combinations of source materials and two types of reagents. Based on the findings, the following conclusions are drawn:  
* The AAEC mixes satisfied the EFNARC [77] criteria for self-consolidating ability. The initial and final setting times ranged from 190 min to 311 min and from 230 min to 369 min, respectively;
* The ternary (fly ash C 'FA-C' + FA-F + ground granulated blast furnace slag 'GGBFS') mixes exhibited higher slump flows than their binary (FA-C + GGBFS) counterparts due to having a lower FA-C/GGBFS content, while the activator/regaent 2 (calcium hydroxide: sodium sulfate = 2.5:1) mixes resulted in higher slump flows due to having lower silica ratio than the mixes that used reagent 1 (calcium hydroxide: sodium metasilicate = 1:2.5);
* The slump flow of the AAECs decreased with an increase in the MWCNT/rGO content, with a few exceptions depending on mix/regaent types, while the addition of MgO showed a less significant decrease. The higher surface area or water affinity of MgO/MWCNTs and higher agglomeration tendency of MWCNTs/rGO were considered contributing factors;
* All AAECs achieved a 28-day compressive strength ranging from 26.0 MPa to 48.5 MPa > 18 MPa and satisfied the criteria for structural concrete. Control binary AAECs obtained higher 28-day compressive strengths than their ternary counterparts, due to the dominant formation of C-A-S-H/C-S-H compared to the dominant formation of amorphous N-C-A-S-H/N-A-S-H in their ternary counterparts. Binary mix B2  
Figure 21: FTIR infrared spectrum of 180-day powder specimens. with reagent 2 exhibited a 22% higher 28-day compressive strength than its ternary counterpart T2 due to having higher FA-C and GGBFS contents;
* The AAECs with reagent 2 generally produced a higher compressive strength compared to their reagent 1 counterparts due to the formation of additional C-S-H gel (in addition to C-A-S-H/N-C-A-S-H or C-A-S-H/C-S-H) and more compact microstructures, as per XRD-SEM analysis, which showed the presence of sharper crystalline peaks of quartz and calcite;
* The addition of 5% MgO increased the 28-day compressive strength (by 19-25%), and UPV exhibited potential self-healing capability due to the formation of well-dispersed fine Mg(OH)\({}_{2}\), hydrotalcite, and M-S-H, which compensated for volume shrinkage and refined the matrix pore size, as confirmed from XRD-SEM/EDS;
* The 28-day compressive strength increased with the increase in MWCNT/rGO content up to 0.3%, indicating it as an optimum dosage. The decrease in strength at higher dosages (>0.3% wt) of MWCNTs/rGO can be compensated for/reversed by using MgO-MWCNT/rGO combinations that show beneficial effects of MgO addition;
* The addition of 0.3% MWCNTs and rGO increased the compressive strength by 9% and 14.8%, respectively, showing a higher effectiveness of rGO in improving strength. The increase in compressive strength and UPV was attributed to the uniform dispersion and good MWCNT-matrix bond bridging cracks (with no newly formed MWCNT reaction products), while the formation of additional zeolites caused matrix densification with the addition of rGO, as confirmed from the SEM/EDS analysis. Proper dispersion of the MWCNTs/rGO is important to avoid agglomeration and negative effects on the workability, mechanical, and micro-structural properties;
* Fourier transform infrared spectrometer (FTIR) analysis suggested the formation of an aluminosilicate network in AAECs with a higher concentration of Si-O-Si bonds, indicating a more stable structure.