###### Abstract
This promising alternative method to produce large-scale production of GONFs is a requirement for introducing GONFs into the concrete industry. One of the major hindrances encountered by previous researches which prevented the introduction of GONFs into concrete (relatively large scale) is the small production of GONFs. This major hindrance can be overcome by addressing this innovative technology. Figure 2 shows the manufacturing process of ball-milling GONF. The other hindrance to introduce GONFs into concrete is the dispersion issue of GONFs in concrete mix. It is well known that the best method for dispersing of GONFs in a solvent such as water is by applying sonication [1; 11]. All previous researchers have used GONF-solution to make GONF-combined cement composites [3; 5; 6; 9; 12]. Originality, the uniqueness of this study, is to disperse GONFs as powder in OPC prior to mixing with water to investigate the feasibility of using GONFs as dry-addition. Some of previous studies have used either surfactant or dispersant with water to  
Figure 1: A proposed chemical reaction pathway for producing graphene oxide (reproduced with permission from [15]. Copyright Elsevier, 2016). improve the dispersion of GONFs [18; 19; 20]. However, none of the previous studies used dry GONF powder for the cement composite mix without applying sonication. In general, concrete mix requires relatively large amounts of water when compared with cement paste mix due to larger scale specimens and structure. Thus, for the design of GONF-combined cement paste mix (relatively small scale), most of the previous studies used GONFs dispersed in water by applying sonication. Figure 3 shows dry GONF powder and GONF dispersed solution. For concrete mix, however, it requires a relatively large quantity of water. Therefore, applying sonication for the dispersion of GONFs into water can be a major issue. The construction industry typically uses ready mixed concrete. Each batch of ready mixed concrete is tailor-made and normally consumes a high volume of water. Even though the sonication method is an effective method to disperse GONFs in water, it has some imitations, especially for high volume process. One of limitations is the difficulty of reproducibility of sonication results. The transmitted energy is highly depending on the location of the probe. In other words, the sonicator has a limited range of transmitted energy around the probe. In this study, two different mix designs were employed to investigate the effect of mix design method on the mechanical properties of OPC based specimens. The applied two mix designs are called Dry- and Wet-mix designs. Dry-mix design indicates the GONF is mixed with cement as a dry power while Wet-mix design signifies that the GONF as a solution (after sonication of GONF with water) is mixed with cement. Dry-mix is more practical and effective for concrete mix due to the ease of preparation, mixing and placing of concrete mix. Wet-mix is useful as a more direct comparison to published literature as a baseline for GONF efficacy in cement and concrete. Figure 3: Graphene oxide nanoflake (GONF): (**a**) Dry GONF powder; (**b**) GONF-solution; and (**c**) the equipment for the ball milling process [16]. Figure 2: Mechanochemical process of producing ball-milling graphene oxide nanoflake (reproduced with permission from [15]. Copyright Elsevier, 2016).