Influence of aggregate type on conversion and strength in calcium aluminate cement concrete

Adams, Matthew P.; Ideker, Jason H.

doi:10.1016/j.cemconres.2017.07.007

Cited by 55 publications

(33 citation statements)

References 24 publications

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“…It is essential to know the components and the characteristics of each element, such as the type and content of sand or fine aggregates, since these physical or chemical characteristics modify, in a different way, the structure of the mixture from workability to performance in the use phase [1]. The sand, or fine aggregate, used for the manufacture of mortars, can come from different sources, such as natural deposits (called natural sand or siliceous sand) or as crushed rock products (like limestone aggregates), each of them having distinctive physical characteristics that influence mortars and concretes differently [2,3]. When it comes to concrete, the mixture volume depends on size distribution and aggregate shape.…”

Section: Introductionmentioning

confidence: 99%

Influence of ZrO2 Nanoparticles on the Microstructural Development of Cement Mortars with Limestone Aggregates

et al. 2019

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In this research, the effect of the addition of zirconium oxide-synthesized nanoparticles on the microstructural development and the physical–mechanical properties of cement mortars with limestone aggregates was studied. Zirconia nanoparticles were synthesized using the co-precipitation method. According to XRD analysis, a mixture of tetragonal (t) and monoclinic (m) zirconia phases was obtained, with average crystallite sizes around 15.18 and 17.79 nm, respectively. Based on the ASTM standards, a mixture design was obtained for a coating mortar with a final sand/cement ratio of 1:2.78 and a water/cement ratio of 0.58. Control mortars and mortars with ZrO2 additions were analyzed for two stages of curing of the mortar—7 and 28 days. According to SEM analysis, mortars with ZrO2 revealed a microstructure with a high compaction degree and an increase in compressive strength of 9% on the control mortars. Due to the aggregates’ characteristics, adherence with the cement paste in the interface zone was increased. It is suggested that the reinforcing effect of ZrO2 on the mortars was caused by the effect of nucleation sites in the main phase C–S–H and the inhibition of the growth of large CH crystals, and the filler effect generated by the nanometric size of the particles. This produced a greater compaction volume, suggesting that faults are probably originated in the aggregates.

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Section: Introductionmentioning

confidence: 99%

Influence of ZrO2 Nanoparticles on the Microstructural Development of Cement Mortars with Limestone Aggregates

et al. 2019

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“…To evaluate the influence of a formation of calcium aluminates hydrate containing silicates (i.e., strätlingite, C 2 ASH 8 ) in the hydration process on the fundamental properties for CAC mortar, three levels of replacement in GGBS (20,40, and 60% by weight of cement) were used in this study. e oxide composition of the binders determined by X-ray fluorescence (XRF) and mix proportions for the specimens are given in Tables 1 and 2, respectively, and also XRD curves of the materials are shown in Figure 1.…”

Section: Experimental Workmentioning

confidence: 99%

“…In particular, CAC 60 showed a remarkable high final strength, reaching beyond 57.5 MPa at 365 days, of which the value is superior to the strength for specimen made with CAC 100%, while CAC 80 and 40 were accounted for 49.4 and 43.8 MPa, respectively. In fact, CAC specimens usually produce the sudden loss of the strength in the hydration period depending on environmental conditions, presumably due to the conversion process, of which hexagonal phases of CAH 10 and C 2 AH 8 formed at normal temperatures would be imposed the transformation into cubic ones (C 3 AH 6 and AH 3 ) [17][18][19][20]. is phenomenon was observed in this study that the strength for CAC 100 rapidly increased up to 7 days then faced a marginal decrease from 40.8 MPa at 7 days to 38.9 MPa at 28 days, which in turn reincreased with time (45.8 MPa at 365 days), presumably due to a further reaction of the remained grains with a released water from the conversion reaction.…”

Section: Development Of Strengthmentioning

confidence: 99%

“…e cubic phases of C 3 AH 6 and AH 3 have the higher density in CAC hydration; therefore, the space filled by lowdensity hexagonal phases of CAH 10 and C 2 AH 8 , which produces a high early strength, would be decreased after the conversion process, resulting in a sudden reduction in the strength [1,13]. Many previous studies [17][18][19][20] reported that long-term properties of CAC concrete exhibited a decreased strength, compared to the strength at early ages. It has been attempted to take some precautions for avoiding/eliminating the transformation of metastable hydrates using chemical and mineral admixtures, to overcome this anxiety about instability to the properties over time.…”

Section: Introductionmentioning

confidence: 99%

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Development of Strength for Calcium Aluminate Cement Mortars Blended with GGBS

Yang

Ann

Jung

2019

Advances in Materials Science and Engineering

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In the present study, the development of strength in different calcium aluminate cement (CAC) mixture mortars with granulated ground blast-furnace slag (GGBS) was investigated. The substitution of GGBS levels was 0, 20, 40, and 60% weight of binder, of which the CAC used in this study naturally contained C2AS clinker as a secondary phase. To activate a hydraulic nature of the phase, in addition to the mineral additive, all specimens were cured at 35 ± 2°C for the first 24 hours and then stored in a 95% humidity chamber at 25 ± 2°C. The penetration resistance of fresh mortar was measured immediately after pouring, and the mortar compressive strength was monitored for 365 days. Simultaneously, to evaluate the hydration kinetics at early ages, in terms of heat evolution, the calorimetric analysis was performed at the isothermal condition (35°C) for 24 hours. The hydration behavior in the long term was characterized by X-ray diffraction, which was supported by microscopic observation using scanning electron microscopy with energy dispersive spectroscopy. Furthermore, an examination of the pore structure was accompanied to quantify the porosity. As a result, it was found that an increase in the GGBS content in the mixture resulted in an increased setting time, as well as total heat evolved for 24 hours in normalized calorimetry curves. In addition, the strength development of mortar showed a continuous increased value up to 365 days, accounting 43.8–57.5 MPa for the mixtures, due to a formation of stratlingite, which was identified at the pastes cured for 365 days using chemical and microscopic analysis. However, GGBS replacement did not affect on the pore size distribution in the cement matrix, except for total intrusion volume.

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“…In contrast, calcium sulfoaluminate cements (hauyne minerals, CSA) have a significantly faster hydration rate than OPC [8][9][10][11]; they have received ongoing research attention since their early strength can be achieved upon substitution in OPC at an optimal ratio-due to the high temperatures involved in the initial hydration reaction [12][13][14][15][16][17][18][19][20]. Additionally, it is possible to secure the formation of a passivation film of the reinforcing steel, in addition to a stable volume due to the excellent initial strength in the early stage, thereby allowing a 28-day design standard early strength to be developed [21,22].…”

Section: Introductionmentioning

confidence: 99%

Effects of Accelerators and Retarders in Early Strength Development of Concrete Based on Low-Temperature-Cured Ordinary Portland and Calcium Sulfoaluminate Cement Blends

Lee¹,

Lee²,

Choi

2020

Materials

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In this study, experiments were performed on the applicability of mortars and concretes based on calcium sulfoaluminate (CSA) binders to facilitate the early strength development of ordinary Portland cement (OPC) under low-temperature conditions. An optimum mixture of CSA was evaluated to improve the early strength of OPC, and the effects of accelerators and retarders on this mixture were examined to demonstrate the applicability of the resulting concrete mixture. Furthermore, mixture applicability was validated by producing concrete at the Remicon Batcher plant and performing numerical simulations. As observed, the optimum CSA substitution rate for the realization of early strength was 17% of the total unit binder amount with CaO/SO3 and SO3/Al2O3 ratios of 1.9 and 1.25, respectively. Evidently, CSA in combination with Na2SO4 as an accelerator promoted the early strength of concrete with OPC and secured its constructability using additional retarders to control the quick setting of concrete. Additionally, the activation of initial hydration at low temperatures yielded a compressive strength of 5 MPa/12 h or higher for the resulting concrete mixture.

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Influence of aggregate type on conversion and strength in calcium aluminate cement concrete

Cited by 55 publications

References 24 publications

Influence of ZrO2 Nanoparticles on the Microstructural Development of Cement Mortars with Limestone Aggregates

Influence of ZrO2 Nanoparticles on the Microstructural Development of Cement Mortars with Limestone Aggregates

Development of Strength for Calcium Aluminate Cement Mortars Blended with GGBS

Effects of Accelerators and Retarders in Early Strength Development of Concrete Based on Low-Temperature-Cured Ordinary Portland and Calcium Sulfoaluminate Cement Blends

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