# Magnesium Oxychloride Cement: Development, Opportunities and Challenges
## 5 Recent Developments in FRMOC-Based Composites  
MOC-based cementitious composites normally have high strength but are brittle in nature [81]. This can be overcome by the use of fibers which are found to impart excellent ductility in OPC-based cementitious composites. This is particularly relevant as it is common practice in the MOC industry to add multiple layers of fiber mesh or grid to increase the flexural strength of MOC boards and decrease the size of the member [2]. However, working efficiency inevitably suffers as a result of the addition of multiple layers of fiber mesh. Thus, FRMOC composite might have the capability of achieving high strength and ductility (high strain capacity), which will not only enhance structural performance and optimize MOC member dimensions, but also increase construction efficiency [2]. Previous studies showed that the MOC-based cementitious composite has an outstanding bonding ability with fibers [31,82]. However, research in this area is very scarce. [PERSON] et al. [81] examined the effect of PE fiber on the performance of MOC composites and found that PE fiber significantly enhanced the tensile behavior, strain hardening capacity, and multi-cracking behavior of MOC composites. Further, they reported that the FRMOC had a tensile strength of above 7 MPa and an improved tensile strain capability of up to 8% (Figure 4). They attributed this to the excellent chemical bonding between fiber and MOC composite matrix. [PERSON] et al. [2] also examined the effect of PE fiber on the behavior of MOC composites and achieved high compressive strength and high tensile ductility. The FRMOC achieved an overall strain-hardening capability of up to 8% (Figure 5). They studied the mechanical properties of FRMOC under different curing periods ranging from 12 h to 28 d and reported that the compressive, tensile, and flexural strength of the FRMOC at 1 d reached 71.4 MPa, 8.28 MPa, and 25.2 MPa, respectively, which accounts for 56%, 75%, and 84% of the equivalent values at 28 d. The water resistance ratios for the compressive and flexural strength of the FRMOC were found to be substantially greater than the corresponding values for the plain MOC. They reported that the compressive and flexural strengths' water resistance ratios for FRMOC (28 d cured) were 0.68 and 0.58, respectively, after 28 d immersion in hot water (60 \({}^{\circ}\)C), whereas the values were 0.35 and 0.25, respectively, for plain MOC. [PERSON] et al. [31] developed MOC-based engineered cementitious composites (MOC-ECC) containing PE fiber (2% by volume) to further extend the application of MOC in the construction industry. They found that the MOC-ECCs have a tensile strength of around 5 MPa and a tensile strain capacity of between 5% to 7%. Also, MOC-ECC demonstrated a saturated fracture pattern, close crack width control under tension, and superior ductility. They recommended that MOC-ECC with enhanced ductility has the potential to introduce construction material free from steel reinforcement and as a  
Figure 3: Strength retention coefficient of MOC cement pastes: (**a**) 7 d and (**b**) 28 d water immersion. Note: F: Fly ash; S: GGBFS; M: Metakaolin-A (alumina-rich kaolinite clay); and K: Metakaolin-B (iron-rich kaolinite clay) [75]. viable solution for steel corrosion that has limited MOC applicability in civil engineering applications. In general, the literature regarding FRMOC containing 2% PE fiber showed a significant improvement in the ductility of the composites (as shown in Figure 4) without compromising the overall mechanical performance. In a recent investigation by [PERSON] et al. [35], the influence of 2% basalt fiber on the mechanical properties of MOC was explored, revealing enhancements in compressive and tensile strengths alongside a notable reduction in strain capacity. In a subsequent study aiming to optimize both tensile strength and strain capacity, [PERSON] et al. [1] delved into the effects of hybrid fibers, specifically PE fiber and basalt fiber, on MOC behavior.