Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications
Calcium silicate hydrate (CSH) gels, the main binding phases of hydrated cement, are the most widely utilized synthetic materials. To understand the influences of composition and polymers on the reaction kinetics and phase formation, CSH gels with varying Ca/Si ratios and amounts of poly (acrylamide...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-01-01
|
| Series: | Gels |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2310-2861/8/2/75 |
| _version_ | 1797479976869560320 |
|---|---|
| author | Amirhossein Madadi Jianqiang Wei |
| author_facet | Amirhossein Madadi Jianqiang Wei |
| author_sort | Amirhossein Madadi |
| collection | DOAJ |
| description | Calcium silicate hydrate (CSH) gels, the main binding phases of hydrated cement, are the most widely utilized synthetic materials. To understand the influences of composition and polymers on the reaction kinetics and phase formation, CSH gels with varying Ca/Si ratios and amounts of poly (acrylamide-co-acrylic acid) partial sodium salt (PAAm-co-PAA) were synthesized via a direct method. The CSH gels were characterized through isothermal calorimetry, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy at different ages. By increasing the Ca/Si ratio from 0.8 to 1.0, the formation of CSH was enhanced with a 5.4% lower activation energy, whereas the incorporation of PAAm-co-PAA increased the temperature sensitivity of the reactions with an 83.3% higher activation energy. In the presence of PAAm-co-PAA, the reaction rate was retarded at an early age and the negative impact faded over time. The results of an XRD analysis indicated the formation of tobermorite as the main phase of the CSH gels, while the addition of PAAm-co-PAA resulted in a postponed calcium hydroxide consumption and CSH formation, which was confirmed by the decreased FTIR intensity of the C=O bond, Si–O stretching and Si–O bonds. The increased Raman vibrations of Si–O–Si bending Q<sup>2</sup>, Ca–O bonds, O–Si–O and asymmetric bending vibrations of SiO<sub>4</sub> tetrahedra in the presence of PAAm-co-PAA indicate the intercalation of the polymeric phase and internal deformation of CSH gels. |
| first_indexed | 2024-03-09T21:53:30Z |
| format | Article |
| id | doaj.art-147d4a8a01e848d5b8322d5e69bc290f |
| institution | Directory Open Access Journal |
| issn | 2310-2861 |
| language | English |
| last_indexed | 2024-03-09T21:53:30Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Gels |
| spelling | doaj.art-147d4a8a01e848d5b8322d5e69bc290f2023-11-23T20:01:18ZengMDPI AGGels2310-28612022-01-01827510.3390/gels8020075Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer ModificationsAmirhossein Madadi0Jianqiang Wei1Department of Civil and Environmental Engineering, Francis College of Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USADepartment of Civil and Environmental Engineering, Francis College of Engineering, University of Massachusetts Lowell, Lowell, MA 01854, USACalcium silicate hydrate (CSH) gels, the main binding phases of hydrated cement, are the most widely utilized synthetic materials. To understand the influences of composition and polymers on the reaction kinetics and phase formation, CSH gels with varying Ca/Si ratios and amounts of poly (acrylamide-co-acrylic acid) partial sodium salt (PAAm-co-PAA) were synthesized via a direct method. The CSH gels were characterized through isothermal calorimetry, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy at different ages. By increasing the Ca/Si ratio from 0.8 to 1.0, the formation of CSH was enhanced with a 5.4% lower activation energy, whereas the incorporation of PAAm-co-PAA increased the temperature sensitivity of the reactions with an 83.3% higher activation energy. In the presence of PAAm-co-PAA, the reaction rate was retarded at an early age and the negative impact faded over time. The results of an XRD analysis indicated the formation of tobermorite as the main phase of the CSH gels, while the addition of PAAm-co-PAA resulted in a postponed calcium hydroxide consumption and CSH formation, which was confirmed by the decreased FTIR intensity of the C=O bond, Si–O stretching and Si–O bonds. The increased Raman vibrations of Si–O–Si bending Q<sup>2</sup>, Ca–O bonds, O–Si–O and asymmetric bending vibrations of SiO<sub>4</sub> tetrahedra in the presence of PAAm-co-PAA indicate the intercalation of the polymeric phase and internal deformation of CSH gels.https://www.mdpi.com/2310-2861/8/2/75calcium silicate hydrate (CSH) gelPAAm-co-PAAthermal analysisreaction rateactivation energy |
| spellingShingle | Amirhossein Madadi Jianqiang Wei Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications Gels calcium silicate hydrate (CSH) gel PAAm-co-PAA thermal analysis reaction rate activation energy |
| title | Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications |
| title_full | Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications |
| title_fullStr | Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications |
| title_full_unstemmed | Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications |
| title_short | Characterization of Calcium Silicate Hydrate Gels with Different Calcium to Silica Ratios and Polymer Modifications |
| title_sort | characterization of calcium silicate hydrate gels with different calcium to silica ratios and polymer modifications |
| topic | calcium silicate hydrate (CSH) gel PAAm-co-PAA thermal analysis reaction rate activation energy |
| url | https://www.mdpi.com/2310-2861/8/2/75 |
| work_keys_str_mv | AT amirhosseinmadadi characterizationofcalciumsilicatehydrategelswithdifferentcalciumtosilicaratiosandpolymermodifications AT jianqiangwei characterizationofcalciumsilicatehydrategelswithdifferentcalciumtosilicaratiosandpolymermodifications |