III. RESULTS AND DISCUSSION
A. Influence of specific gravity to water to binder ratio of M-S-H binder
In development of M-S-H binder with magnesium oxide and silica fume, it is noted that silica fume has rather low specific gravity (S.G) and bulk density compared to Portland cement (PC). Thus, use of high silica fume content in the binder consequently results in a binder system of low specific gravity and bulk density, compared to PC.
The light weight binder leads to a difference in water to binder ratio (by mass), compared to PC. To compare water content by mass of M-S-H and PC, let’s consider a given water amount in a fixed binder volume V¬b, calculation of the difference of water to binder ratio by mass is derived from (4): (4) where Vb = absolute volume of the binder wMSH = weight of M-S-H binder in a binder volume of Vb wPC = weight of PC …show more content…
Scanning electron microscopy (SEM) analysis
SEM analysis is performed to investigate effect of morphology of the binder constituents to workability of the paste and mortar. The SEM images give information on the particles size, shape and surface texture as displayed in Fig. 6, Fig. 7.
As shown in Fig. 6, MgO particles’ shape is angular with unpolished and rough surface texture due to ground effect. The angularity and rough surface result in the increase in dilatancy, viscosity and improper compaction by vibration method. Therefore, there is an optimal MgO content for workability at which the flow will decrease if MgO content exceeds the optimal value.
Due to the compactness under pressure, Fig. 1 shows the condensed silica fume consists of agglomerations whose median particle size is about 88 µm. However, the original particles of condensed silica fume are very fine (d50 = 0.1 µm) with spherical shape and can be observed from high magnification SEM images (Fig. 7). The agglomerations of condensed silica fume are broken up in mixing resulting in original microfine particles of silica fume in the
A. Influence of specific gravity to water to binder ratio of M-S-H binder
In development of M-S-H binder with magnesium oxide and silica fume, it is noted that silica fume has rather low specific gravity (S.G) and bulk density compared to Portland cement (PC). Thus, use of high silica fume content in the binder consequently results in a binder system of low specific gravity and bulk density, compared to PC.
The light weight binder leads to a difference in water to binder ratio (by mass), compared to PC. To compare water content by mass of M-S-H and PC, let’s consider a given water amount in a fixed binder volume V¬b, calculation of the difference of water to binder ratio by mass is derived from (4): (4) where Vb = absolute volume of the binder wMSH = weight of M-S-H binder in a binder volume of Vb wPC = weight of PC …show more content…
Scanning electron microscopy (SEM) analysis
SEM analysis is performed to investigate effect of morphology of the binder constituents to workability of the paste and mortar. The SEM images give information on the particles size, shape and surface texture as displayed in Fig. 6, Fig. 7.
As shown in Fig. 6, MgO particles’ shape is angular with unpolished and rough surface texture due to ground effect. The angularity and rough surface result in the increase in dilatancy, viscosity and improper compaction by vibration method. Therefore, there is an optimal MgO content for workability at which the flow will decrease if MgO content exceeds the optimal value.
Due to the compactness under pressure, Fig. 1 shows the condensed silica fume consists of agglomerations whose median particle size is about 88 µm. However, the original particles of condensed silica fume are very fine (d50 = 0.1 µm) with spherical shape and can be observed from high magnification SEM images (Fig. 7). The agglomerations of condensed silica fume are broken up in mixing resulting in original microfine particles of silica fume in the