Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste
| Autor: | Elżbieta Janowska-Renkas |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
maleic superplasticizer chemical structure SP
cement Technology Calcium Sulphate (CaSO4 0211 other engineering and technologies 02 engineering and technology Calorimetry CaSO4·2H2O and CaSO4·0.5H2O) Article chemistry.chemical_compound Viscosity Rheology 021105 building & construction Side chain General Materials Science hydrophilicity of SP polymer Carboxylate Cement Microscopy QC120-168.85 QH201-278.5 Superplasticizer Backbone chain Engineering (General). Civil engineering (General) 021001 nanoscience & nanotechnology TK1-9971 Descriptive and experimental mechanics chemistry Chemical engineering acrylic superplasticizer rheology Electrical engineering. Electronics. Nuclear engineering TA1-2040 0210 nano-technology calorimetry |
| Zdroj: | Materials, Vol 14, Iss 2683, p 2683 (2021) Materials Volume 14 Issue 10 |
| ISSN: | 1996-1944 |
| DOI: | 10.3390/ma14102683 |
| Popis: | The paper presents test results of the impact of sulphate ions from calcium sulphates: Hemihydrate, dihydrate and anhydrite, on rheological properties and hydration heat of cement pastes with, and without, superplasticizers, derivatives of maleic (SP-2) and acrylic (SP-1) acids. It is demonstrated that cement pastes fluidity depends on superplasticizer chemical structure, and its effect is expressed by a hydrophilic coefficient. As maleic superplasticizers have flexible comb-like structure composed of a shorter backbone chain containing COO− carboxylate groups and very long side chains, cement pastes showed higher fluidity than with acrylic superplasticizer with ladder-like structure, longer backbone chains with shorter side chains. SP-1 showing lower hydrophilicity coefficient and fewer COO− groups was found to be less sensitive to increased sulphate ion content in pastes. However, with SP-2 with higher hydrophilicity, a gradual fluidity loss (increased paste viscosity) was observed. Plastic viscosity was approximately at the same level in SP-1-containing pastes. Tests showed that sulphates definitely changed polycarboxylate superplasticizers performance. A high concentration of sulphate ions reduced maleic superplasticizer efficiency. Under these conditions, SP-1 is more effective and therefore more suitable for fluidity of pastes containing higher SO42− ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer. |
| Databáze: | OpenAIRE |
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