Report of TC 238-SCM: hydration stoppage methods for phase assemblage studies of blended cements—results of a round robin test

Snellings, Ruben; Chwast, Jacek; Çizer, Özlem; Belie, Nele De; Dhandapani, Yuvaraj; Durdzinski, Pawel; Elsen, Jan; Haufe, Johannes; Hooton, R.D.; Patapy, Cédric; Santhanam, Manu; Scrivener, Karen; Snoeck, Didier; Steger, Laurent; Sui, Tongbo; Vollpracht, Anya; Winnefeld, Frank; Lothenbach, Barbara

doi:10.1617/s11527-018-1237-5

Cited by 147 publications

(50 citation statements)

References 14 publications

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“…The diffraction patterns of the hardened paste specimens were analyzed using the Crystallography Open Database (COD). To stop the hydration at a certain curing date, specimens were soaked in isopropyl alcohol, washed with diethyl ether, and subsequently dried under 40 • C [18][19][20]. To identify the amount of amorphous phase in the XRD analysis, crystalline TiO 2 (SRM 674b, NIST, Gaithersburg, MD, USA) was used as an internal standard (TiO 2 : paste = 1:9).…”

Section: Compressive Strength Developmentmentioning

confidence: 99%

Heat-Induced Acceleration of Pozzolanic Reaction Under Restrained Conditions and Consequent Structural Modification

Lee

Jeong²,

Kang

et al. 2020

Materials

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This study investigated the heat-induced acceleration of cement hydration and pozzolanic reaction focusing on mechanical performance and structural modification at the meso- and micro-scale. The pozzolanic reaction was implemented by substituting 20 wt.% of cement with silica fume, considered the typical dosage of silica fume in ultra-high performance concrete. By actively consuming a limited amount of water and outer-formed portlandite on the unreacted cement grains, it was confirmed that high-temperature curing greatly enhances the pozzolanic reaction when compared with cement hydration under the same environment. The rate of strength development from the dual reactions of cement hydration and pozzolanic reaction was increased. After the high-temperature curing, further strength development was negligible because of the limited space availability and preconsumption of water under a low water-to-cement environment. Since the pozzolanic reaction does not directly require the anhydrous cement, the reaction can be more easily accelerated under restrained conditions because it does not heavily rely on the diffusion of the limited amount of water. Therefore, it significantly increases the mean chain length of the C–S–H, the size of C–S–H globules with a higher surface fractal dimension. This finding will be helpful in understanding the complicated hydration mechanism of high-strength concrete or ultra-high performance concrete, which has a very low water-to-cement ratio.

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Section: Compressive Strength Developmentmentioning

confidence: 99%

Heat-Induced Acceleration of Pozzolanic Reaction Under Restrained Conditions and Consequent Structural Modification

Lee

Jeong²,

Kang

et al. 2020

Materials

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“…X-ray powder diffraction (XRD) analysis was conducted on the raw materials (natural zeolite sand and calcined zeolite sand) and the samples (after 28 days of curing) after the hydration stoppage treatment. The solvent exchange method was used for hydration stoppage of the hydrated samples [35]. We ground the 5 g of hydrated samples into a powder.…”

Section: X-ray Diffractionmentioning

confidence: 99%

Effect of Pre-Wetted Zeolite Sands on the Autogenous Shrinkage and Strength of Ultra-High-Performance Concrete

Zhang

Wang

2020

Materials

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In this study, the carrier effect of zeolite sands in reducing the autogenous shrinkage and optimizing the microstructure of ultra-high-performance concrete (UHPC) is studied. Pre-wetted calcined zeolite sand (CZ), calcined at 500 °C for 30 min, and natural zeolite sand (NZ), with 15 wt.% and 30 wt.% in UHPC, are used to partially replace standard sands. On that basis, a series of experiments are executed on the developed UHPC, including compressive strength, autogenous shrinkage, X-ray diffraction (XRD), and isothermal calorimetry experiments. With the increase of the zeolite sand content, the autogenous shrinkage of UHPC decreases gradually. Moreover, when the added CZ content is 30 wt.% (CZ30 specimen), it is effective in reducing autogenous shrinkage. Meanwhile, at the age of 28 days, the compressive strength of CZ30 is 97% of the control group. In summary, it is possible to effectively reduce the autogenous shrinkage of UHPC containing 30 wt.% CZ, without sacrificing its mechanical properties.

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“…On the 28th day, the hydrated paste was crushed and ground into a powder. Thereafter, the hydration reaction of the samples was stopped using isopropanol and diethyl-ether, according to the solvent exchange method [ 58 , 59 ]. After the pretreatment, the powders were placed on sample holders and then mounted on an X ray diffractometer (SmartLab SE, Rigaku, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

Performance Comparison between Densified and Undensified Silica Fume in Ultra-High Performance Fiber-Reinforced Concrete

2020

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Silica fume (SF) is a key ingredient in the production of ultra-high performance fiber-reinforced concrete (UHPFRC). The use of undensified SF may have an advantage in the dispersion efficiency inside cement-based materials, but it also carries a practical burden such as high material costs and fine dust generation in the workplace. This study reports that a high strength of 200 MPa can be achieved by using densified SF in UHPFRC with Portland limestone cement. Additionally, it was experimentally confirmed that there was no difference between densified and undensified SFs in terms of workability, compressive and flexural tensile strengths, and hydration reaction of the concrete, regardless of heat treatment, because of a unique mix proportion as well as mixing method for dispersing agglomerated SF particles. It was experimentally validated that the densified SF can be used for both precast and field casting UHPFRCs with economic and practical benefits and without negative effects on the material performance of the UHPFRC.

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Report of TC 238-SCM: hydration stoppage methods for phase assemblage studies of blended cements—results of a round robin test

Cited by 147 publications

References 14 publications

Heat-Induced Acceleration of Pozzolanic Reaction Under Restrained Conditions and Consequent Structural Modification

Heat-Induced Acceleration of Pozzolanic Reaction Under Restrained Conditions and Consequent Structural Modification

Effect of Pre-Wetted Zeolite Sands on the Autogenous Shrinkage and Strength of Ultra-High-Performance Concrete

Performance Comparison between Densified and Undensified Silica Fume in Ultra-High Performance Fiber-Reinforced Concrete

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