Evaluation of the green coconut fiber compatibility with cement by using different calculation methods

Using all the different methods reported in the literature, the compatibility of coconut green fiber with Portland cement in five different compounds was evaluated. For each trace, the mixtures hydration curves (temperature x time) were obtained by the use of type K thermocouples and an analog signal receiver. Based on a unique set of experiments with coconut fiber, a comprehensive critical review of the methods reported in the literature was performed to evaluate fiber-cement compatibility. Contradictory results about compatibility classification were obtained using different compatibility equations. The correlations between compatibility and compressive-strength essays results were considered to support our choice of the best method of compatibility calculation. Greater sensitivity to capture the differences in the compositions of mixtures and a higher correlation with the compressive strength of composites revealed that the CX calculation method, which considers the heat release rate as a basic parameter, presented more realistic results.

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Influence and Mechanism Research of Hydration Heat Inhibitor on Low-Heat Portland Cement

Frontiers in Materials ◽

10.3389/fmats.2021.697380 ◽

2021 ◽

Vol 8 ◽

Author(s):

Fujie Jia ◽

Yan Yao ◽

Jingyu Wang

Keyword(s):

Compressive Strength ◽

Sustained Release ◽

Portland Cement ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Setting Time ◽

Hydration Heat ◽

Adiabatic Temperature Rise ◽

Mechanism Research

A kind of microcapsule sustained-release–type hydration heat inhibitor (MSR) was prepared. The effect of MSR on semi-adiabatic temperature rise, setting time, and strength of low-heat Portland cement was investigated. Microcalorimetry, XRD, SEM, and TG-DSC were used to investigate the mechanism of MSR on hydration of low-heat Portland cement. The results showed that the MSR had good regulating effect on hydration of low-heat Portland cement. When the dosage of MSR was 0.3%, the heat release rate decreased by 10% and the peak temperature decreased by 52%. The 3D compressive strength decreased by 50%, and the 28-day strength was the same as control. The MSR can delay the hydration of low-heat Portland cement by inhibiting the heat release rate of C2S and C3S minerals.

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Portland Cement Based Lightweight Multifunctional Matrix with Different Kind of Additives Containing SiO2

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.604.305 ◽

2014 ◽

Vol 604 ◽

pp. 305-308 ◽

Cited By ~ 3

Author(s):

Ina Pundienė ◽

Modestas Kligys ◽

Jurga Šeputytė-Jucikė

Keyword(s):

Compressive Strength ◽

Heat Release ◽

Heat Release Rate ◽

Release Rate ◽

Dynamic Viscosity ◽

Building Materials ◽

Hydration Process ◽

Aerated Concrete ◽

Wetting Heat ◽

Pozzolanic Properties

Additives containing SiO2 (ACS) and having pozzolanic properties such as metakaolin (MK), microsilica (MS) and milled autoclaved aerated concrete waste (MAACW) are promising materials for partially replacement of Portlandcement (PC) in matrix of lightweight building materials. Studies have shown that SA effects on the hydration process of PC matrix. The highest wetting heat release rate values were obtained using MS additive, and the lowest a mix of MS and MK additives. In a mix with both MS and MK additives, the maximal value of heat release rate was reached after 10 h and in a mix with MS additive after 13 h. MS additive extends while MK additive accelerates the hydration process of PC. The most effective plasticizer (P) was chosen according to the study of dynamic viscosity (DV) of PC matrix. It was fixed that surfactant (SU) in amount of 0.03 % (from PC) reduces the density of matrix about 30 % compared with the density of matrix without SU. Increased quantity of MAACW (from 5 to 15 % from PC) causes in increase of compressive strength of PC matrix (after 28 days curing) from 19 to 47 MPa.

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Development of vegetable oil-based conducting rigid PU foam

e-Polymers ◽

10.1515/epoly-2019-0042 ◽

2019 ◽

Vol 19 (1) ◽

pp. 411-420 ◽

Cited By ~ 10

Author(s):

Anuja Agrawal ◽

Raminder Kaur ◽

R.S. Walia

Keyword(s):

Electrical Conductivity ◽

Compressive Strength ◽

Carbon Fibre ◽

Heat Release ◽

Release Rate ◽

The Other ◽

Rigid Polyurethane Foam ◽

Fibre Concentration ◽

Pu Foam ◽

Flame Retardant Properties

AbstractIn this study, carbon fibre powder has been used as reinforcement to enhance the electrical conductivity of bio-based rigid polyurethane foam. Effect of carbon fibre incorporation on the mechanical, thermal and flame retardant properties has also been investigated. Results concluded that the foams with 8% carbon fibre concentration showed up to 288% increase in compressive strength. Furthermore, up to 28% decrease in the peak of heat release rate (PHRR) was observed on the incorporation of carbon fibre powder. Additionally, the rate of smoke production was also found decreased for carbon fibre reinforced foams. Foams with 8% and 10% carbon fibre concentration show conductivity of 1.9 × 10-4 and 7.1 × 10-4 S/m, respectively. So, carbon fibre powder may be used as a potential filler to enhance the electrical conductivity of rigid foams without compromising the other properties.

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