Phase development in normal and ultra high performance cementitious systems by quantitative X-ray analysis and thermoanalytical methods

Korpa, Arjan; Kowald, Torsten; Trettin, R.

doi:10.1016/j.cemconres.2008.11.003

Cited by 174 publications

(50 citation statements)

References 15 publications

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“…Fig. 1 shows the time dependent phase development in OC and UHPC at room temperature [4]. It can be seen that the content of crystalline phases was considerably higher in OC, whereas less amorphous phases in the UHPC were measured.…”

Section: Hydrationmentioning

confidence: 94%

“…The fact that no calcite was detected by X-rays in UHPC even after 28 days may be interpreted as indication of no considerable phase carbonation in this specimen. The variations of ettringite content development between the first and second hydration day indicate that some conversion of ettringite to monosulfate phase is possible, and that significant amount of aluminate may enter the X-ray amorphous C-S-H phases [4].…”

Section: Hydrationmentioning

confidence: 99%

See 1 more Smart Citation

A review on ultra high performance concrete: Part II. Hydration, microstructure and properties

Wang

Shi

et al. 2015

Construction and Building Materials

680

169

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Section: Hydrationmentioning

confidence: 94%

Section: Hydrationmentioning

confidence: 99%

A review on ultra high performance concrete: Part II. Hydration, microstructure and properties

Wang

Shi

et al. 2015

Construction and Building Materials

680

169

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“…As shown in Fig. 8, the density and homogeneity of the matrix microstructure of SC-UHPC mortars is almost the same to the conventional UHPC at the same steam curing condition of 90 ºC (Yazıcı et al 2008;Korpa et al 2009;Yazıcı et al 2010), and much higher than that of normal concrete and high performance concrete (HPC). Nevertheless, very low amount of entrapped air pores was found in the SC-UHPC matrix.…”

Section: Microstructure Analysismentioning

confidence: 71%

Properties of Ultra High Performance Concrete Containing Superfine Cement and without Silica Fume

Xiao

Deng

Shen³

2014

ACT

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To avoid the disadvantages caused by using silica fume, by using superfine cement (SC) to substitute silica fume, a new kind of ultra high performance concrete (SC-UHPC) was prepared and introduced. The influence of component types and dosages on the mechanical properties of SC-UHPC was investigated. The results show that 40% ground granulated blast furnace slag (GGBFS) or 10% fly ash (FA) & 30% GGBFS replacing SC are the most appropriate proportions to get high strength with satisfied workability and low cost. A suitable amount of defoaming agent (DA) in superplasticizer (SP) effectively reduced the void ratio in the UHPC. To optimize the strength and fluidity, the rational natural sand distribution with lowest clay particles amount can be used. The small sized steel fibers added into the mixture effectively improved the flexural behavior of SC-UHPC. Multiple nonlinear analysis show that, with sufficient calcium silicate hydrate (C-S-H gel) and enough mixture fluidity, the compressive strength of UHPC is closely related to the water to binder ratio and void ratio, and increases linearly with the incremental fiber amount. Microstructure analysis proved that the microstructure of SC-UHPC has ultra high density and homogeneity.

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“…28,29 The phase composition of this cement calculated by the quantitative X-ray diffraction (QXRD) method is given in Table 1 and its chemical composition and specific surface area is given in Table 2. 30 Microscale pozzolanic additives. The same silica fume (SF) type G983 and fly ash (SWF) products as used in our previous studies were used as microscale pozzolanic additives (Figs 1(b) and (c)).…”

Section: Methodsmentioning

confidence: 99%

Very high early strength of ultra-high performance concrete containing nanoscale pozzolans using the microwave heat curing method

Korpa¹,

Trettin²

2008

Advances in Cement Research

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This paper deals mainly with the application of a microwave heat curing method to ultra-high strength and performance concrete specimens made up of combinations of micro and nanoscale pozzolans. The application of this curing method enables very high early strength, as high as 420 MPa to be obtained after 1 day by a total microwave curing duration of 2 h. In addition it was observed that the achieved strength depended on the kind of nanoscale pozzolan (oxide) used and on the microwave energy, time of treatment and treatment duration. In comparison with the oven curing method this method has the advantages of much shorter curing times and better curing efficiency. The microwave curing of ultra-high performance concrete seems to be very advantageous for applications where extreme concrete strength in very short time is required. IntroductionUltra-high performance concrete, which is a modern building material with outstanding strength (in excess of 150 MPa), durability and performance, is characterised by a very dense structure and its production is based on the design of composite systems with highly compatible, well graded components. The approach to the production of ultra-high performance concrete (UHPC) makes use of some new processing methods associated with both chemical and physical properties. The processing methods which are related to the chemical properties involve the use of admixtures that reduce the water demand (i.e. superplasticiser polymolecules) and of components (additives) that contribute to an increase in the composite structure density through the production of additional material with very fine porosity (i.e. pozolanically reacting additives). 1-6 The processing methods associated with the physical properties aim to achieve very high density and strength and involve the development of techniques for the designing, casting and curing treatment of the composite. The physical processing methods may be grouped according to the time at which they take part in the action as follows: the pre-mixing processing that is carried out prior to mixing with water (or water and admixtures); the processing during mixing; and the after mixing (post-mixing) processing.The pre-mixing processing comprises among others the selection of raw components, adjusting of their size distributions and of the overall granular grading by making use of models to increase the packing density through mineral blends of different granulometry. 7,8 During examination of the models that aim to increase the packing density, it was found that an extension of the number of granular classes and expansion of the acceptable granular size range by using ultrafine nanoscale additives can lead to an additional increase in the density and considerable improvements to the properties. 9-11 The pre-mixing and processing during mixing together enable the production of concrete with very high strength, durability and performance, 12-14 whereas the post-mixing processing, which can be applied optionally in those cases when extreme properties (i.e....

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Phase development in normal and ultra high performance cementitious systems by quantitative X-ray analysis and thermoanalytical methods

Cited by 174 publications

References 15 publications

A review on ultra high performance concrete: Part II. Hydration, microstructure and properties

A review on ultra high performance concrete: Part II. Hydration, microstructure and properties

Properties of Ultra High Performance Concrete Containing Superfine Cement and without Silica Fume

Very high early strength of ultra-high performance concrete containing nanoscale pozzolans using the microwave heat curing method

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