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A mild alkali treated jute fibre controlling the hydration behaviour of greener cement paste.

Jo BW, Chakraborty S - Sci Rep (2015)

Bottom Line: To reduce the antagonistic effect of jute fibre on the setting and hydration of jute reinforced cement, modified jute fibre reinforcement would be a unique approach.The present investigation deals with the effectiveness of mild alkali treated (0.5%) jute fibre on the setting and hydration behaviour of cement.Additionally, from the analytical characterizations, it is determined that fibre-cement compatibility is increased and hydration delaying effect is minimized by using alkali treated jute fibre as fibre reinforcement.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental engineering, Hanyang University, Seoul, South Korea, 133791.

ABSTRACT
To reduce the antagonistic effect of jute fibre on the setting and hydration of jute reinforced cement, modified jute fibre reinforcement would be a unique approach. The present investigation deals with the effectiveness of mild alkali treated (0.5%) jute fibre on the setting and hydration behaviour of cement. Setting time measurement, hydration test and analytical characterizations of the hardened samples (viz., FTIR, XRD, DSC, TGA, and free lime estimation) were used to evaluate the effect of alkali treated jute fibre. From the hydration test, the time (t) required to reach maximum temperature for the hydration of control cement sample is estimated to be 860 min, whilst the time (t) is measured to be 1040 min for the hydration of a raw jute reinforced cement sample. However, the time (t) is estimated to be 1020 min for the hydration of an alkali treated jute reinforced cement sample. Additionally, from the analytical characterizations, it is determined that fibre-cement compatibility is increased and hydration delaying effect is minimized by using alkali treated jute fibre as fibre reinforcement. Based on the analyses, a model has been proposed to explain the setting and hydration behaviour of alkali treated jute fibre reinforced cement composite.

No MeSH data available.


SEM images of raw and alkali treated jute fibres as well as raw and alkali treated jute fibre reinforced cement samples.(a) Raw jute fibre, (b) alkali treated (0.5%, 24 h) jute fibre, (c) control cement paste, (d) raw jute reinforced cement paste, and (e) alkali treated jute reinforced cement paste.
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f5: SEM images of raw and alkali treated jute fibres as well as raw and alkali treated jute fibre reinforced cement samples.(a) Raw jute fibre, (b) alkali treated (0.5%, 24 h) jute fibre, (c) control cement paste, (d) raw jute reinforced cement paste, and (e) alkali treated jute reinforced cement paste.

Mentions: Raw jute fibre contains organic components such as hemicelluloses, lignin, pectin, and other compounds18. Accordingly, the jute fibre leaches loosely bonded organic compounds during mixing with a highly alkaline (pH ~ 12.76) cement matrix. These organic compounds are responsible for delaying the cement hydration reaction by either forming a protective layer around the partially reacted cement grain (Fig. 3(a)), or forming a chelate complex with the cations present in the hydrated cement1213. Additionally, the chelation of the sugars with the cations present in hydrated cement may disturb the cement hydration reaction equilibrium and minimize the nucleation and growth of the hydrated cement product. However, alkali treatment removes the soluble sugars from the jute fibre1718. This statement can be supported by FTIR analysis (Fig. 4) as well as SEM analysis (Figs. 5(a) and 5(b)) of the raw and alkali treated jute fibres. As indicated in Fig. 4, several peaks appear in the FTIR spectra of raw and alkali treated jute fibre due to the presence of the different functional groups reported by Roy et al.18. The most important characteristic peak appears at 1739 cm−1 for raw jute fibre and is absent for alkali treated jute fibre, indicating that the alkali treatment removes the loosely bonded hemicelluloses. It is reported that the absorption band at 1739 cm−1 appears to be due to the C = O stretching of the ester linkage in hemicelluloses18. Thus, from the FTIR analysis of the jute fibres, it is assumed that the alkali treatment is able to remove the loosely bonded soluble sugars from the jute fibre. Therefore, the mixing of the alkali treated jute fibre with the cement matrix reduces the possibility of the sugar leaching into the cement system, which minimizes the ion capturing possibility from the cement matrix. It is also reported by Roy et al.18 that the alkali treatment of jute fibre removes the soluble sugars from the fibre as well as increases the surface roughness, and alkali treatment splits the fibres into fibrils. Figs. 5(a) and 5(b) show SEM images of the raw as well as mild alkali (0.5%) treated jute fibres; the figures show that the surface roughness as well as the effective surface area of the jute fibre increase after alkali treatment. The increased surface roughness, as well as the fibrillation of the jute fibres due to alkali treatment, increase the effective surface area for bonding between the fibre and the matrix. Those factors may enhance fibre-matrix compatibility which improves the overall performances of alkali treated jute fibre reinforced cement composite. Figs. 5(c), 5(d) and 5(e) represent the SEM images of the fracture surface of control, raw jute and mild alkali treated jute reinforced cement samples hydrated for 28 days. In Fig. 5(c), adequate hairline cracks are clearly observed in the micrograph of the control cement paste. However, no such cracks are observed in the micrographs of the raw and alkali treated jute reinforced cement samples (Figs. 5(d) and 5(e), respectively. Additionally, a compact contact in between alkali treated jute fibres and the cement matrix apparent in the alkali treated jute cement sample (Fig. 5(e)) but not in the raw jute cement sample (Fig. 5(d)). Therefore, it can be concluded that the fibre matrix compatibility increases due to alkali treatment of the jute fibre. Moreover, based on the results, the alkali treated jute fibre reinforcement increases the cement hydration reaction product compared to that of the raw jute reinforced cement sample, but the alkali treated jute fibre reinforced cement sample still produces a less hydrated product than the control cement sample. This seems to be due to the bonding between internal cellulose chains of jute fibre with the cement matrix (Fig. 3(b)), which may enhance the fibre-matrix compatibility and enhances the strength of alkali treated jute fibre reinforced cement composite. Therefore, it is concluded that the mild alkali treated jute fibre reinforcement increases the fibre-cement compatibility as well as reduces the hydration delaying activity as compared to that of the raw jute fibre reinforcement. Additionally, the mild alkali treated jute fibre reinforcement would be an initial alternative approach to develop sustainable and green construction material.


A mild alkali treated jute fibre controlling the hydration behaviour of greener cement paste.

Jo BW, Chakraborty S - Sci Rep (2015)

SEM images of raw and alkali treated jute fibres as well as raw and alkali treated jute fibre reinforced cement samples.(a) Raw jute fibre, (b) alkali treated (0.5%, 24 h) jute fibre, (c) control cement paste, (d) raw jute reinforced cement paste, and (e) alkali treated jute reinforced cement paste.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4296306&req=5

f5: SEM images of raw and alkali treated jute fibres as well as raw and alkali treated jute fibre reinforced cement samples.(a) Raw jute fibre, (b) alkali treated (0.5%, 24 h) jute fibre, (c) control cement paste, (d) raw jute reinforced cement paste, and (e) alkali treated jute reinforced cement paste.
Mentions: Raw jute fibre contains organic components such as hemicelluloses, lignin, pectin, and other compounds18. Accordingly, the jute fibre leaches loosely bonded organic compounds during mixing with a highly alkaline (pH ~ 12.76) cement matrix. These organic compounds are responsible for delaying the cement hydration reaction by either forming a protective layer around the partially reacted cement grain (Fig. 3(a)), or forming a chelate complex with the cations present in the hydrated cement1213. Additionally, the chelation of the sugars with the cations present in hydrated cement may disturb the cement hydration reaction equilibrium and minimize the nucleation and growth of the hydrated cement product. However, alkali treatment removes the soluble sugars from the jute fibre1718. This statement can be supported by FTIR analysis (Fig. 4) as well as SEM analysis (Figs. 5(a) and 5(b)) of the raw and alkali treated jute fibres. As indicated in Fig. 4, several peaks appear in the FTIR spectra of raw and alkali treated jute fibre due to the presence of the different functional groups reported by Roy et al.18. The most important characteristic peak appears at 1739 cm−1 for raw jute fibre and is absent for alkali treated jute fibre, indicating that the alkali treatment removes the loosely bonded hemicelluloses. It is reported that the absorption band at 1739 cm−1 appears to be due to the C = O stretching of the ester linkage in hemicelluloses18. Thus, from the FTIR analysis of the jute fibres, it is assumed that the alkali treatment is able to remove the loosely bonded soluble sugars from the jute fibre. Therefore, the mixing of the alkali treated jute fibre with the cement matrix reduces the possibility of the sugar leaching into the cement system, which minimizes the ion capturing possibility from the cement matrix. It is also reported by Roy et al.18 that the alkali treatment of jute fibre removes the soluble sugars from the fibre as well as increases the surface roughness, and alkali treatment splits the fibres into fibrils. Figs. 5(a) and 5(b) show SEM images of the raw as well as mild alkali (0.5%) treated jute fibres; the figures show that the surface roughness as well as the effective surface area of the jute fibre increase after alkali treatment. The increased surface roughness, as well as the fibrillation of the jute fibres due to alkali treatment, increase the effective surface area for bonding between the fibre and the matrix. Those factors may enhance fibre-matrix compatibility which improves the overall performances of alkali treated jute fibre reinforced cement composite. Figs. 5(c), 5(d) and 5(e) represent the SEM images of the fracture surface of control, raw jute and mild alkali treated jute reinforced cement samples hydrated for 28 days. In Fig. 5(c), adequate hairline cracks are clearly observed in the micrograph of the control cement paste. However, no such cracks are observed in the micrographs of the raw and alkali treated jute reinforced cement samples (Figs. 5(d) and 5(e), respectively. Additionally, a compact contact in between alkali treated jute fibres and the cement matrix apparent in the alkali treated jute cement sample (Fig. 5(e)) but not in the raw jute cement sample (Fig. 5(d)). Therefore, it can be concluded that the fibre matrix compatibility increases due to alkali treatment of the jute fibre. Moreover, based on the results, the alkali treated jute fibre reinforcement increases the cement hydration reaction product compared to that of the raw jute reinforced cement sample, but the alkali treated jute fibre reinforced cement sample still produces a less hydrated product than the control cement sample. This seems to be due to the bonding between internal cellulose chains of jute fibre with the cement matrix (Fig. 3(b)), which may enhance the fibre-matrix compatibility and enhances the strength of alkali treated jute fibre reinforced cement composite. Therefore, it is concluded that the mild alkali treated jute fibre reinforcement increases the fibre-cement compatibility as well as reduces the hydration delaying activity as compared to that of the raw jute fibre reinforcement. Additionally, the mild alkali treated jute fibre reinforcement would be an initial alternative approach to develop sustainable and green construction material.

Bottom Line: To reduce the antagonistic effect of jute fibre on the setting and hydration of jute reinforced cement, modified jute fibre reinforcement would be a unique approach.The present investigation deals with the effectiveness of mild alkali treated (0.5%) jute fibre on the setting and hydration behaviour of cement.Additionally, from the analytical characterizations, it is determined that fibre-cement compatibility is increased and hydration delaying effect is minimized by using alkali treated jute fibre as fibre reinforcement.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental engineering, Hanyang University, Seoul, South Korea, 133791.

ABSTRACT
To reduce the antagonistic effect of jute fibre on the setting and hydration of jute reinforced cement, modified jute fibre reinforcement would be a unique approach. The present investigation deals with the effectiveness of mild alkali treated (0.5%) jute fibre on the setting and hydration behaviour of cement. Setting time measurement, hydration test and analytical characterizations of the hardened samples (viz., FTIR, XRD, DSC, TGA, and free lime estimation) were used to evaluate the effect of alkali treated jute fibre. From the hydration test, the time (t) required to reach maximum temperature for the hydration of control cement sample is estimated to be 860 min, whilst the time (t) is measured to be 1040 min for the hydration of a raw jute reinforced cement sample. However, the time (t) is estimated to be 1020 min for the hydration of an alkali treated jute reinforced cement sample. Additionally, from the analytical characterizations, it is determined that fibre-cement compatibility is increased and hydration delaying effect is minimized by using alkali treated jute fibre as fibre reinforcement. Based on the analyses, a model has been proposed to explain the setting and hydration behaviour of alkali treated jute fibre reinforced cement composite.

No MeSH data available.