## 3 Specimen Preparation and Concrete Manufacturing Process  
It is essential to point out that each laboratory programs discussed in this review paper utilized a specific standard (e.g., Australian standard, American Society for Testing and Materials (ASTM), British standard) for the preparation of concrete specimens. The number of combinative materials participating in concrete mix design have a notable role in the improvement of concrete properties, hence the limitations have been considered for utilizing the source materials of concrete types in a number of standards. For instance, the amount of silica in the case of ultra-high-performance concrete (UHPC), as the new generation of concrete with higher strength, should not exceed 11% based on German (DIN) standard. Therefore, in the laboratory program conducted by [PERSON] and [PERSON] [14], the UHPC mixture was experimentally examined using an amount of only 10% microsilica in accordance with DIN EN 12390-3 and DIN EN 12390-5 [14; 15].  
In this part, the most common method typically utilized for preparing concrete specimens in all standards is briefly described as follows:  
* coarse and fine aggregates along with PCC and pozzolanic admixtures such as FA were quantified before mixing. Fine aggregates (Figure 1a) [16] commonly consist of sand or crushed stone, including most particles with a size smaller than 5 mm (0.2 in). Coarse aggregates (Figure 1b) [16] consist of a combination of gravels or crushed stone with a size larger than 5 mm, which is between 9.5 mm and 37.5 mm based on ASTM standard [17].
* To make chemical solutions, sodium hydroxide (SH) pellets and sodium silicate (SS) powders were separately blended with water in the Na\({}_{2}\)SiO\({}_{3}\)/NaOH ratio of 2.5 to produce alkaline liquid with different molarities. This liquid was provided 24 h before mixing day. The alkaline solutions should be mixed as it causes the polymerization to be more easily formed based on Davidovits [18]. Generally, the manufacturing process, which is approximately similar in all standards, can be categorized into three steps:  
Step 1: All solid materials were mixed around 3 min after quantifying by concrete mixer. The value used was considered based on the calculation of the number of specimens used in this part of laboratory work.  
Step 2: The alkaline solutions previously prepared 24 h before blending materials were poured over the solid materials for the mixes containing diverse dosages of fly ash or other pozzolanic admixture as the replacement of Portland cement. Consequently, they were mixed together for approximately four minutes.  
Step 3: Before casting fresh concrete, the workability was immediately measured through a slump test. Subsequently, the produced concrete was poured into the cube molds with the standard dimensions of 150 \(\times\) 150 \(\times\) 150 mm\({}^{3}\) to reduce the voids of concrete by compacting action on the vibrating table for 1-2 min. After this period, the specimens were exposed to the oven under the curing condition which was 110 \({}^{\circ}\)C, and the samples were removed from the oven after 24 h. Subsequently, theses specimens were kept at the usual temperature (room heat) between 14-17 \({}^{\circ}\)C for 4-5 h, and eventually the specimens were put in a water bath at a temperature of 21\({}^{\circ}\)-23 \({}^{\circ}\)C until commencing the compressive tests at 7, 28, and 90 days into this study.  
As for the other concrete mixtures, the cube specimens were covered by a film to lessen water evaporation happening over the curing condition and were maintained in the molds for 24 h at room temperature (14-17 \({}^{\circ}\)C) to deter the drastic change of environment which can happen over this period. Consequently, the specimens were taken out from the molds and were kept in a water bath at a temperature of around 20 \({}^{\circ}\)C until the strength tests at 7, 28, and 90 days [15; 19; 20].