Approaches to achieve fluidity retention in low-carbon calcined clay blended cements

Li, Ran; Lei, Lei; Sui, Tongbo; Plank, Johann

doi:10.1016/j.jclepro.2021.127770

Cited by 29 publications

(11 citation statements)

References 27 publications

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“…With the combination of an additional 0.03% bwob. of SG (such a rate is commonly used in practice) the fluidity retention time was prolonged to 90 min, which indicates the well-known synergistic effect between HRM-PCE and the retarder [9]. The slump retention effect of sodium gluconate has been extensively studied previously and can be attributed to the postponed formation of ettringite [14].…”

Section: Slump Retention Ability Of Conventional Readymix Pce and Pce...mentioning

confidence: 96%

“…The preparation of Ca-Al-PCE-LDH nanocomposite was prepared via rehydration of C3A according to the method described by Li et al [9]. During the synthesis, the selfprepared methacrylate ester PCE 45PC6 was used.…”

Section: Ca-al-ldh Nanocompositementioning

confidence: 99%

“…Conventional technologies for achieving slump retention in OPC are based on the encapsulation and delayed addition of PCE superplasticizers, a more detailed description can be found in the previous literature [9]. The intercalation of PCE superplasticizers into layered double hydroxides (LDHs) [10] is considered as a promising new approach to improve fluidity retention in calcined clay blended cements.…”

Section: Introductionmentioning

confidence: 99%

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PCE Superplasticizers for Calcined Clay Blended Cements – Challenges and Solutions

Chen,

Li,

Thienel

et al. 2023

ce papers

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A high content of metakaolin in calcined clay blended cement has a positive effect on the early strength development, however, it also leads to a poor workability. Moreover, slump retention is more difficult to achieve in this system than in OPC or other composite cements. In this study, several approaches were investigated to achieve fluidizing ability of mortars prepared from composite cements holding 30 wt. % of calcined clay with varying amounts of metakaolin (∼ 23 wt.%, ∼ 51 wt.%). First, it was found that the slump retaining performance of a common industrial ready‐mix type HPEG PCE rapidly decreases when the content of metakaolin increases. Furthermore, a combination of the ready‐mix HPEG PCE and a retarder (sodium gluconate) which is commonly applied in ready‐mix concrete, also fails to improve fluidity retention in calcined clay blended cement with a high level of metakaolin, hence highlighting the difficulty of slump retention for such cements. To mitigate this problem, a unique admixture based on the combination of a precast type HPEG PCE and a novel PCE‐LDH nanocomposite is introduced. Mortar tests reveal that the high water‐reducing (precast) type HPEG PCE and the PCE‐LDH nanocomposite enables to achieve a remarkable improvement in fluidity retention of such calcined clay blended cements.

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Section: Slump Retention Ability Of Conventional Readymix Pce and Pce...mentioning

confidence: 96%

Section: Ca-al-ldh Nanocompositementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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PCE Superplasticizers for Calcined Clay Blended Cements – Challenges and Solutions

Chen,

Li,

Thienel

et al. 2023

ce papers

Self Cite

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“…To test the fluidity, the slurry was prepared by gradually increasing the content of calcined clay (1% to 5%) with a water-binder ratio of 0.29 and a 1% polycarboxylate superplasticizer. The flow test for specimen workability was carried out in accordance with ASTM standards [21]. The mixing slurry was injected into the truncated cone mold (upper diameter Φ36 mm, lower diameter Φ60 mm, and height 60 mm).…”

Section: Sample Preparation and Characterizationmentioning

confidence: 99%

Hydration Characteristics and Mechanical Properties of Cement-Based Materials Modified by Calcined Zeolite and Montmorillonite

Qin¹,

Zhou²,

Yan³

et al. 2023

Journal of Renewable Materials

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Montmorillonite and clinoptilolite zeolite were used as representative materials to prepare calcined clay-cement binary cementitious materials in order to study the effect of calcination treatment on the activation of clay minerals and the activity difference between layered and framed clays in this research. The influence of different calcined clay content (2%, 4%, 6%, 8%, 10%) on the fluidity, compressive strength, microstructure, phase change, and hydration heat of cement-based materials were analyzed. The calcined clay improves the fluidity of cement-based materials as compared with the uncalcined group. The addition of calcined montmorillonite (CMT) improves the development of mechanical strength, and the optimal compressive strength reaches 85 MPa at 28 days with 8% CMT. However, the activity of calcined clinoptilolite zeolite (CZL) is weak with few reaction sites, which slightly reduced the mechanical strength as compared to the blank sample. The addition of CMT changes the microscopic morphology of hydration products such as C-S-H and C-A-H, leading to the formation and transformation of ettringite in the early stage. It promotes the gradual polymerization of Si-O bonds into Si-O-Si bonds simultaneously, which accelerates the early hydration process. However, CZL acts mainly as a filling function in the cementitious system. In brief, CMT as an admixture can improve the mechanical properties of cement, but CZL has little effect. This work provides a guideline for the applications of calcined clay in cement, considering the influence of clay type on workability and mechanical strength.

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“…21,22 Furthermore, the raw materials for calcined clay, such as low-quality tailings or waste clay, are widely available, and substituting PC with LC3 on a large scale is a feasible and effective strategy to implement the CPCN strategy in China. Recent, researches on LC 3 are very active around the world based on local clay resources, mainly focusing on its mix design, 23 short-term mechanical properties, [24][25][26] admixture compatibility, 27,28 bond performance between LC 3 and reinforcement, 29 and early physical and chemical properties. 30 However, to the best knowledge of the authors, most investigations on LC 3 are limited to nonstructural elements, 31 and the structural performance of LC 3 -RC beams and columns is not well understood.…”

Section: Introductionmentioning

confidence: 99%

Shear design and life cycle assessment of novel limestone calcined clay cement reinforced concrete beams

Huang

Deng

Zhao

et al. 2023

Structural Concrete

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To reduce the impact on global warming, many countries and regions are advocating the use of low‐carbon and green supplementary cementitious materials (SCMs) to improve the cement industry. This study investigates the shear behavior of reinforced concrete (RC) beams made with a novel green concrete, limestone, calcined clay, and cement clinker (LC3). Full‐scale shear tests were conducted on RC and LC3‐RC beams to evaluate their fundamental behavior for structural applications. The shear resistance of LC3 concrete beams was evaluated using Chinese, American, and Eurocode codes, while carbon emission and environmental impact were analyzed by life cycle assessment (LCA). Results showed that LC3‐RC and RC beams exhibited similar shear behavior in terms of crack initiation, propagation, and development. The increase in concrete strength improved the stiffness of LC3‐RC specimens, while RC specimens remained unchanged. The ductility of RC specimens was inversely proportional to concrete strength, while LC3‐RC beams exhibited optimal ductility. The increase in stirrup ratio significantly improved the shear resistance of both LC3‐RC and RC beams. With increased shear‐span ratio, the failure mode of LC3 specimens improved, changing from diagonal‐compression to shear compression or diagonal tension failure. The shear resistance of both LC3‐RC and RC beams was underestimated by GB 50010‐2010, ACI 318‐19, and Eurocode 2. LC3 concrete significantly reduced energy consumption and carbon emissions and achieved favorable environmental benefits in terms of GWP, PMFP, POFP, TAP, and TETP. Increasing usage of limestone in LC3 may further decrease environmental potential without sacrificing mechanical properties. The findings of this study contribute to the development of sustainable and environmentally friendly structures in engineering.

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Approaches to achieve fluidity retention in low-carbon calcined clay blended cements

Cited by 29 publications

References 27 publications

PCE Superplasticizers for Calcined Clay Blended Cements – Challenges and Solutions

PCE Superplasticizers for Calcined Clay Blended Cements – Challenges and Solutions

Hydration Characteristics and Mechanical Properties of Cement-Based Materials Modified by Calcined Zeolite and Montmorillonite

Shear design and life cycle assessment of novel limestone calcined clay cement reinforced concrete beams

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