Journal: Cement and Concrete Composites

Abbreviation

Cem. concr. compos.

Publisher

Elsevier

Journal Volumes

ISSN

0958-9465
1873-393X

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Publications1 - 10 of 49
  • Pore structure of mortars with cellulose ether additions - Mercury intrusion porosimetry study
    Item type: Journal Article
    Wyrzykowski, M.; Kiesewetter, R.; Kaufmann, J.; et al. (2014)
    Cement and Concrete Composites
  • Early-age hydration of accelerated low-carbon cements for digital fabrication
    Item type: Journal Article
    Das, Arnesh; Wenger, Cedric; Walpen, Lukas; et al. (2025)
    Cement and Concrete Composites
    Digital fabrication processes with concrete offer several advantages compared to conventional processes, however, a major criticism with related concrete mixes has been with regard to their high cement paste content and consequent carbon footprint. One of the ways to address this is to reduce ordinary Portland cement (OPC) content in such mixes by using supplementary cementitious materials. This paper reports on such an approach for two different digital fabrication methods: digital casting system and 3D concrete printing. Results focus on the combined use of such low carbon blends with a calcium aluminate cement (CAC) based accelerator. Two such accelerators were studied: one being mainly crystalline based and the other mainly amorphous. Their performance is assessed at different temperatures. It is concluded that crystalline CAC is more suitable for applications above 20 °C while at temperature below 20 °C, amorphous CAC should be preferred. This paper also delves deeper into the effect of amorphous CAC on the hydration of tricalcium silicate present in OPC. It shows that the effect of amorphous CAC on that silicate depends on the OPC content of the system as well as on the type and amount of calcium sulfate used in the accelerator formulation.
  • Reactivity of kaolinitic clays calcined in the 650 °C–1050 °C temperature range: Towards a robust assessment of overcalcination
    Item type: Journal Article
    Zunino, Franco; Scrivener, Karen (2024)
    Cement and Concrete Composites
    Using calcined clays as supplementary cementitious materials is one of the main solutions available for a substantial and widespread reduction of the clinker factor in cement. Thus, understanding the phenomena governing their production process and reactivity is crucial for a successful technological deployment. In this study, the mineralogical and physical changes experienced by kaolinitic clays calcined within 650 and 1050 °C were explored, with emphasis on the identification of overcalcination. It was observed that the decrease in reactivity above the optimum calcination temperature is associated with the formation of Al–Si spinel and a decrease in specific surface area, which is linked to a modification of the pore size distribution within the particles. Differential scanning calorimetry (DSC) was identified as the most robust, and repeatable technique to identify an overcalcined kaolinitic clay. In combination with thermogravimetric analysis (TGA), it can provide a complete calcination process overview, relevant for quality control purposes.
  • Layer interface characteristics and adhesion of 3D printed cement-based materials exposed to post-printing temperature disturbance
    Item type: Journal Article
    Zhang, Yi; Tao, Yaxin; Godinho, Jose R.A.; et al. (2025)
    Cement and Concrete Composites
    The layer interface, which is vital for the performance and longevity of 3D printed cement-based materials (3DPCM), is very sensitive to the environmental conditions because of the lack of formwork. Nevertheless, the current limited understanding of how temperature affects the layer interface has restricted the application of 3D printing in different construction scenarios. Here, we revealed the effects of temperature on the multi-scale phase distribution features of the layer interface through mercury intrusion porosimetry, X-ray computed tomography, nanoindentation and scanning electron microscopy with energy dispersive spectroscopy techniques. Additionally, the interlayer bond strength of 3DPCM was evaluated via the splitting tensile test. Small amplitude oscillation, surface roughness and isothermal calorimetry measurements were employed for an in-depth analysis of the mechanisms. Results indicate that an increase in temperature post-printing reduces the discrepancies in aggregate volume fraction between the layer interface and bulk matrix due to the increasing structuration rate and the amount of cement paste at the interface due to the reduced settlement of aggregates. The porosity difference between the layer interface and bulk matrix decreased with increasing temperature due to the pore size refinement by faster filling with hydrates. In addition, a more concentrated distribution of atomic ratios and elastic modulus of hydrates were observed at the layer interface of 3DPCM hardened at higher temperatures. Increased curing temperature improves the interlayer bond strength of 3DPCM owing to the enhanced aggregate interlocking, reduced porosity and improved high-density CSH content.
  • Impact of admixtures on the plastic shrinkage cracking of self-compacting concrete
    Item type: Journal Article
    Leemann, Andreas; Nygaard, Peter; Lura, Pietro (2014)
    Cement and Concrete Composites
  • Mitigation of plastic shrinkage cracking with natural fibers - kenaf, abaca, coir, jute and sisal
    Item type: Journal Article
    Lura, Pietro; Toropovs, Nikolajs; Justs, Janis; et al. (2025)
    Cement and Concrete Composites
    In this study, a number of different fibers - namely kenaf, jute, abaca, coir and sisal - were investigated as natural alternatives to polypropylene (PP) fibers for reducing plastic shrinkage cracking. The risk of plastic shrinkage cracking of mortars with water-to-cement ratio 0.5 containing either 0.6 or 0.9 kg/m3 of natural fibers was assessed according to the ASTM C1579-21 standard and compared with plain mortars and mortars with PP fibers. The water absorption of the natural fibers was low enough that (at the employed dosages) the effect on the workability and on other fresh properties was small. The natural fibers also had no measurable influence on cement hydration in the examined mortars, as revealed by isothermal calorimetry. The best performance in reducing the width of plastic shrinkage cracks was shown by kenaf and jute fibers at the dosage of 0.6 kg/m3, which outperformed even a higher dosage of PP fibers (0.9 kg/m3). Kenaf fibers in pellets, which are advantageous for dosing and mixing, performed similarly as loose fibers. The distribution of both loose and pelletized kenaf fibers in the mortars was studied by X-ray tomography, showing no substantial difference between the two ways of delivering the fibers.
  • A Rheometric Approach to Investigate the Effect of Cellulose ether on Crack Mitigation in Earth-based Concrete
    Item type: Journal Article
    Assunção, Julie; Brumaud, Coralie; Habert, Guillaume (2025)
    Cement and Concrete Composites
    This study investigates the impact of cellulose ethers (CE), particularly Hydroxyethyl Methyl Cellulose (HEMC), on the properties of earth-concrete mixes, focusing on both micro and macro-scale analyses. At the micro-scale, CE's influence on rheological responses and particle interactions was examined, revealing the formation of a robust network that enhances critical strain and yield stress, particularly with higher viscosity polymers. Analysis of total organic carbon in the pore solution indicated partial polymer adsorption, crucial for bridging solid particles and strengthening interparticle interactions. Moving to the macro-scale evaluation, in terms of compressive strength at 28 days, a notable increase was observed. Regarding shrinkage reduction, no clear correlation was found between polymer addition and shrinkage decrease in both stabilized and unstabilized earth mixes. Moreover, CE significantly mitigated crack formation in macro-scale samples, with the most pronounced effect seen in stabilized earth mixes—83% of tested mixes showed improvement compared to 45% in unstabilized mixes. The presence of CaCO3 formation further suggests its influence when combined with cellulose-based polymers. In conclusion, CE enhances the mechanical properties of earth-concrete mixes, offering promising applications in sustainable construction practices.
  • Contraction gradient induced microcracking in hardened cement paste
    Item type: Journal Article
    Bisschop, Jan; Wittel, Falk K. (2011)
    Cement and Concrete Composites
    Drying induced cracking of concrete surfaces and repair layers is a common problem. A principal cause for this type of cracking is the moisture and resulting contraction gradient that develops in the cement paste matrix upon drying. This phenomenon has been experimentally quantified in unconfined hardened cement paste samples using a fluorescent resin impregnation technique. The effects of sample thickness and drying method on surface crack density and crack penetration depth are reported and explained. Finite element modelling of moisture gradients indicate the important role of the film coefficient in desiccation cracking of unconfined samples. The critical thickness for samples to remain crack-free upon drying was in the range of 2–5 mm depending on drying method. In thicker samples a crack spacing doubling process was observed that is in agreement with theoretical predictions.
  • Visco-elastic behavior of blended cement pastes at early ages
    Item type: Journal Article
    Hu, Zhangli; Hilaire, Adrien; Wyrzykowski, Mateusz; et al. (2020)
    Cement and Concrete Composites
  • Active rheology control of cementitious materials containing hard magnetic particles: Sustained response after magnetic intervention
    Item type: Journal Article
    Zhang, Yiyuan; Tao, Yaxin; Dai, Xiaodi; et al. (2025)
    Cement and Concrete Composites
    The performance of responsive cementitious materials after magnetic intervention plays an important role for the application of active rheology control. For example, during 3D concrete printing, the material needs to sustain the increased rheological properties (e.g. yield stress, etc.) after an intervention in the nozzle to guarantee buildability. This research investigates the use of hard magnetic particles to make sure that the responsive cementitious materials sustain their response after a magnetic intervention. The remanent rheological, microstructural and magnetic properties of responsive cementitious materials after a magnetic intervention were studied. Effects of magnetic flux densities (0 T, 0.3 T, and 0.6 T) and magnetic intervention durations (5 s, 60 s, and 180 s) were investigated and compared. Small amplitude oscillation shear (SAOS) tests were performed to determine the rheological properties including yield stress and structural build-up of responsive cementitious materials. The distribution of hard magnetic particles in the magneto-responsive cementitious materials was investigated by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDX). The magnetization of magneto-responsive paste was determined by a vibrating sample magnetometry (VSM). A new type of innovative magneto-responsive cementitious materials was developed, which can sustain a significant magneto-rheological response after the intervention of only a few seconds. The degree of response after a magnetic intervention was heavily influenced by the magnetic flux density instead of intervention duration. The remanent alignment and remanent magnetization of magneto-responsive particles in the cementitious materials were verified and confirmed by experimental results.
Publications1 - 10 of 49