## 6 Conclusions  
In recent decades, the usage of pozzolanic cementitious materials as sustainable substitute of PPs is a central issue in which researchers are centralizing on the concrete properties, which have key roles in the improvement of concrete performance against environmental factors. Hence, it seems that concrete durability is the most significant concrete property to be considered initially in each investigation. Indeed, major durability issues are related to sulphate attack and acid attack chloride penetration. The reduction of concrete permeability in order to improve the durability of concrete is a significant method, which can be considered by adding SPs to reduce the W/C ratio, leading to the reduction of concrete porosity. On the other hand, this decrement in the amount of concrete permeability also leads to the enhancement of concrete compressive strength, implying its dual efficiency on the development of concrete properties. Other secondary parameters such as FA percentage in concrete mixes, SP type, C/A ratio and SS/SH should be accurately assessed while preparing concrete mixes for experimental testing. The following conclusions can be drawn:  
* Temperature is one of the significant factors inducing the reduction in bond strength, when GPC is exposed to temperatures over 300 \({}^{\circ}\)C.
* Generally, GPC demonstrates similar or better performance for bond properties in comparison with OPC [27].
* For the percentage of pozzolanic material, the improvement of mechanical properties such as compressive strength and flexural strength in these concrete types can be seen in the range of 30-50% of PC replacement ratio at 28 days [39; 45]. On the contrary, the increase of composite reinforced materials such as rubber fiber in concrete content leads to the reduction in flexural strength and elasticity modulus of both GPC and OPC while increasing rubber fiber from 0% to 30% cement by weight, as rubber fiber has this capability to provide a better bridge between propagated cracks [28].
* The ratio of SS/SH ratio and SH concentration are two key factors for the improvement of GPC properties compared to OPC concrete [25; 31; 46; 47]. The optimum SS/SH ratio for less workability is 2.5 compared to the GPC mixes with the ratios of 1.5 and 2 [31].  
After assessing all experimental attempts from preliminary literatures discussed in this review paper, the combination of modified Portland cement (PC) types such as OPC and type V containing a lower percentage of calcium (Ca) and higher amounts of Silica (Si) with pozzolanic materials can play the remarkable role in the improvement of concrete properties, especially for compressive strength and other concrete properties. Furthermore, this combinative green concrete mixture can help to significantly reduce the CO\({}_{2}\) emission due to PC production in the atmosphere. However, this does not necessarily mean that the effects of other factors and ambient conditions discussed in this review paper can be ignored, but it is only a comparative assessment subjected to the influencing factors on the development of concrete properties considering eco-friendly criterion.  
Regarding conceptualization, data curation, formal analysis, investigation, resources, methodology, writing, and project administration, all authors have provided the same contribution. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.