Mineral admixtures in mortars

Lawrence, P.; Cyr, Martin; Ringot, Erick

doi:10.1016/s0008-8846(03)00183-2

Cited by 357 publications

(71 citation statements)

References 19 publications

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“…In case of WSA0 and WSA15, the PAI value was found to be lower because of low values of specific surface area. The lowest PAI of wheat straw ash without grinding is due to the dilution effect [77]. Cordeiro et al [78] evaluated the influence of particle size and specific surface area of rice husk ash on the PAI and found that PAI increased with the increase in fineness of RHA.…”

Section: Pozzolanic Activity Index (Grinding)mentioning

confidence: 99%

Environmentally Friendly Utilization of Wheat Straw Ash in Cement-Based Composites

et al. 2018

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The open burning of biomass residue constitutes a major portion of biomass burning and leads to air pollution, smog, and health hazards. Various alternatives have been suggested for open burning of crop residue; however, each of them has few inherent drawbacks. This research suggests an alternative method to dispose wheat straw, i.e., to calcine it in a controlled environment and use the resulting ash as a replacement of cement by some percentage in cement-based composites. When wheat straw, an agricultural product, is burned, it is very rich in SiO 2 , which has a pozzolanic character. However, the pozzolanic character is sensitive to calcination temperature and grinding conditions. According to the authors' best knowledge, until now, no systematic study has been devised to assess the most favorable conditions of burning and grinding for pozzolanic activity of wheat straw ash (WSA). Hence, a systematic experimental program was designed. In Phase I, calcination of WS was carried out at 500 • C, 600 • C, 700 • C, and 800 • C for 2 h. The resulting ashes were tested for color change, weight loss, XRD, XRF, Chapelle activity, Fratini, and pozzolanic activity index (PAI) tests. From test results, it was found that beyond 600 • C, the amorphous silica transformed into crystalline silica. The WSA calcined at 600 • C was found to satisfy Chapelle and Fratini tests requirements, as well as the PAI requirement of ASTM at 28 days. Therefore, WSA produced at 600 • C (WSA600) showed the best pozzolanic performance. In Phase II, WSA600 was ground for various intervals (15-240 min). These ground ashes were tested for SEM, Blaine fineness, Chapelle activity, Fratini, and PAI tests. From test results, it was observed that after 120 min of grinding, there was an increase of 48% in Blaine surface area, with a consequence that WSA-replaced cement cubes achieved a compressive strength almost similar to that of the control mix. Conclusively, wheat straw calcined at 600 • C and ground for 120 min was found to be the most effective way to use pozzolanic material in cement-based composites. The addition of WSA in cement-based composites would achieve manifold objectives, i.e., aiding in the production of environmentally friendly concrete, the use of wheat straw as fuel for electricity production, and adding economic value to wheat straw.

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Section: Pozzolanic Activity Index (Grinding)mentioning

confidence: 99%

Environmentally Friendly Utilization of Wheat Straw Ash in Cement-Based Composites

et al. 2018

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“…The content of dehydrated Ca(OH) 2 in SPM cured for 28 days with the content of SP. 34,35 Moreover, the natural hydration process was disturbed by the SP lms formed around the cement particles. † Meanwhile, the excess SP caused decreased Ca(OH) 2 content, which was decreased by approximately 10.1 wt% for SPM20.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of a new cement-based composite with sulfur polymer

Kwon

Noh

et al. 2015

RSC Adv.

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The addition of sulfur polymer (SP) and the resulting effects on the hydration and physical properties of polymer-cement mortars were investigated. Sulfur polymer-cement mortars (SPMs) with 5 wt%, 10 wt%, and 20 wt% of SPs were prepared to evaluate the compressive strength and impermeability in comparison to ordinary Portland cement mortars (PCMs). After curing for 28 days, the compressive strength of SPM with 5 wt% of SP increased by approximately 8.0% compared to PCM by hardened SP binder as well as proper hydration of hydrates. The impermeability of SPMs cured for 28 days was two times higher than that of PCM cured for the same period. The outstanding enhancement of the compressive strength and impermeability are attributed to SP additive formed inside the hydrated cement. † Electronic supplementary information (ESI) available: SEM images, schematic illustration, chemical composition and physical properties of Portland cement, experimental variable, and content of dehydrated calcium hydroxide. See

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“…However, the use of fillers results in dilution of Portland cement particles in the paste. Above a critical amount of fillers, this ‘dilution’ effect will lead to a lower strength of the hardened paste or concrete [1,7,8]. Besides, the mechanical properties of the interface between filler and hydration products have a significant influence on the development of the fracture process in blended cement paste under a compressive/tension load and, thus, the strength of the cement paste blended with fillers [9,10].…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling of the Effect of Filler/Matrix Interfacial Strength on the Fracture of Cementitious Composites

et al. 2018

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The interface between filler and hydration products can have a significant effect on the mechanical properties of the cement paste system. With different adhesion properties between filler and hydration products, the effect of microstructural features (size, shape, surface roughness), particle distribution and area fraction of filler on the fracture behavior of a blended cement paste system is supposed to be different, as well. In order to understand the effect of the microstructural features, particle distribution and area fraction of filler on the fracture behavior of a blended cement paste system with either strong or weak filler-matrix interface, microscale simulations with a lattice model are carried out. The results show that the strength of the filler-matrix interface plays a more important role than the microstructural features, particle distribution and area fraction of filler in the crack propagation and the strength of blended cement paste. The knowledge acquired here provides a clue, or direction, for improving the performance of existing fillers. To improve the performance of fillers in cement paste in terms of strength, priority should be given to improving the bond strength between filler particles and matrix, not to modifying the microstructural features (i.e., shape and surface roughness) of the filler.

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Mineral admixtures in mortars

Cited by 357 publications

References 19 publications

Environmentally Friendly Utilization of Wheat Straw Ash in Cement-Based Composites

Environmentally Friendly Utilization of Wheat Straw Ash in Cement-Based Composites

Preparation and characterization of a new cement-based composite with sulfur polymer

Numerical Modelling of the Effect of Filler/Matrix Interfacial Strength on the Fracture of Cementitious Composites

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