Abstract
This article presents a research into the impact of plasticising admixtures on drying shrinkage of cementitious composites by evaluating the effectiveness of plasticising. Materials used in the study: Portland cement CEM I 42.5 R, plasticiser LS (modified lignosulphonates based), superplasticiser PCE (synthetic polycarboxylate esters based), superplasticiser MAP (modified acrylic polymers based), sand and water. The percentage change of plastic viscosity of cement paste indicates the effectiveness of plasticising of cementitious composites. The change of plastic viscosity has been tested by adding a specific amount of plasticising admixtures. The effectiveness of plasticising of pastes were tested using rotational viscometer. Chemical admixtures content in pastes varied from 0 to 1.2%. Drying shrinkage was tested based on length change of the specimens with fine aggregates. The method to minimise drying shrinkage of composites was established through use of plasticising admixtures. It has been found that by increasing plasticising admixture dosage from 0 to 1.2% the following changes occur: LS plasticising effectiveness increases by 35% while drying shrinkage decreases by 8%; MAP plasticising effectiveness increases by 70% while drying shrinkage decreases by 16%; PCE plasticising effectiveness increases by 80% while drying shrinkage decreases by 20%.
Highlights
Ever since Joseph Aspdin took out a patent for Portland Cement in 1824, users strove to make structures including it more reliable and stable (Biernacki et al, 2017)
The superplasticiser based on synthetic polycarboxylate ester (PCE) and the superplasticiser based on modified acrylic polymers (MAP) intensively and significantly increases the effectiveness of plasticising from 38 to 72 and from 30 to 63%, respectively, when the dosage of the respective superplasticiser is increased from 0.2 to 0.8% of the cement weight
Summarizing the results obtained (Figure 5), it can be argued that the superplasticiser based on synthetic polycarboxylate ester (PCE) has a greater effectiveness in plasticising and reduction of water demand of the modified Portland cement paste, than the plasticiser based on modified lignosulphonates (LS) and the superplasticiser based on modified acrylic polymers (MAP)
Summary
Ever since Joseph Aspdin took out a patent for Portland Cement in 1824, users strove to make structures including it more reliable and stable (Biernacki et al, 2017). The problems caused by it are of different significance, depending on the structure or surface in question, and of virtually universal occurrence Since this deformation is characterised by long-term manifestation with ensuing problems, drying shrinkage is problematic for concrete structures, especially reinforced (Biernacki et al, 2017). When the surrounding humidity is lower than that of a concrete structure, drying naturally occurs, potentially leading to shrinkage and/or cracking This is linked to rise of capillary pressure, disjoining pressure and surface energy which creates internal compressive stresses in the solid skeleton (Meschke, Pichler, & Rots, 2018). This article evaluates the impact of plasticizing admixtures on drying shrinkage of cementitious composites by evaluating the effectiveness of plasticising
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
