Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste
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 t...
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MDPI AG
2021-05-01
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| Online Access: | https://www.mdpi.com/1996-1944/14/10/2683 |
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| author | Elżbieta Janowska-Renkas |
| author_facet | Elżbieta Janowska-Renkas |
| author_sort | Elżbieta Janowska-Renkas |
| collection | DOAJ |
| description | 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<sup>−</sup> 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<sup>−</sup> 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 SO<sub>4</sub><sup>2−</sup> ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer. |
| first_indexed | 2024-03-10T11:13:05Z |
| format | Article |
| id | doaj.art-3b8561e178e940ad8e3ffe7d0b413c90 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T11:13:05Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-3b8561e178e940ad8e3ffe7d0b413c902023-11-21T20:36:58ZengMDPI AGMaterials1996-19442021-05-011410268310.3390/ma14102683Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement PasteElżbieta Janowska-Renkas0Department of Building Materials Engineering, Faculty of Civil Engineering, Opole University of Technology, Katowicka 48, 45-061 Opole, PolandThe 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<sup>−</sup> 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<sup>−</sup> 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 SO<sub>4</sub><sup>2−</sup> ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer.https://www.mdpi.com/1996-1944/14/10/2683cementCalcium Sulphate (CaSO<sub>4</sub>CaSO<sub>4</sub>·2H<sub>2</sub>O and CaSO<sub>4</sub>·0.5H<sub>2</sub>O)rheologycalorimetryacrylic superplasticizer |
| spellingShingle | Elżbieta Janowska-Renkas Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste Materials cement Calcium Sulphate (CaSO<sub>4</sub> CaSO<sub>4</sub>·2H<sub>2</sub>O and CaSO<sub>4</sub>·0.5H<sub>2</sub>O) rheology calorimetry acrylic superplasticizer |
| title | Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste |
| title_full | Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste |
| title_fullStr | Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste |
| title_full_unstemmed | Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste |
| title_short | Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste |
| title_sort | impact of sulphate ions content on performance of maleic and acrylic superplasticizers in cement paste |
| topic | cement Calcium Sulphate (CaSO<sub>4</sub> CaSO<sub>4</sub>·2H<sub>2</sub>O and CaSO<sub>4</sub>·0.5H<sub>2</sub>O) rheology calorimetry acrylic superplasticizer |
| url | https://www.mdpi.com/1996-1944/14/10/2683 |
| work_keys_str_mv | AT elzbietajanowskarenkas impactofsulphateionscontentonperformanceofmaleicandacrylicsuperplasticizersincementpaste |