Surface Modification of Nano-SiO₂ Particles with Polycarboxylate Ether-Based Superplasticizer under Microwave Irradiation

Abstract

The mechanical properties and durability of cement‐based materials reinforced by nano‐SiO2 (NS) particles are strongly dependent on the dispersion characteristics of the latter. This study presents an innovative eco‐friendly method, which improves the distribution of NS particles through their surface modification using polycarboxylate ether‐based (PCE) superplasticizer containing silane coupling agent under microwave irradiation. The above method ensures the formation of a core‐shell‐shell structure, wherein the PCE shell exhibits enhanced electrostatic and steric hindrance repulsion properties. Moreover, after the surface modification, an improved compatibility between NS and PCE and a higher dispersion stability of NS in the saturated calcium hydroxide solution are attained, which is proved by the respective grafting ratios and encapsulation parameters of the surface‐modified NS particles. The proposed method application guarantees an enhanced fluidity of a fresh cement paste, which makes it lucrative for the production of critical components from nano‐reinforced cement‐based materials.

The Influence of Water Reducing Agents on Early Hydration Property of Ferrite Aluminate Cement Paste

“…After 11 h, peak intensity of the hydration product increased, indicating that more ettringite formed. While, because Al(OH) 3 and Fe(OH) 3 gels were poorly crystallized or amorphous, they were not detected in the pastes. It was observed that the incorporation of PC significantly lowered the characteristic peak of ettringite compared with the blank FAC sample at the ages of 5 h and 11 h, which is consistent with the setting time and hydration heat tests.…”

“…As the most important building material, Portland cement has been widely used in engineering construction worldwide. However, in the manufacturing process of Portland cement clinker, the decarbonation and calcination process produce approximately 5-8% of global anthropogenic CO 2 emissions [1][2][3][4][5]. One of the ways to reduce CO 2 emission from Portland cement production is to replace Portland cement with Calcium sulfoaluminate.…”

Preparation and Properties of Polycarboxylate Superplasticizer Based on Chain Transfer Agents with Various Structures

“…As observed, the broad peak at 3490 cm À 1 was identified as the characteristic peak of À OH in PCE. The peak at 2880 cm À 1 corresponded to the À CÀ H group, and the peak at 1160 cm À 1 was attributed to the vibrational peak of CÀ OÀ C. [32,33] The characteristic peak of C=C in chain transfer agent, which was supposed to appear at 1630 cm À 1 , was not observed. Overall, the three sulfhydryl chain transfer agents had the chain transfer effect, realizing the successful polymerization of PCE.…”

Influence of functionalized nanosilica with different functional groups in the properties of cementitious composites: A review

“…To answer these challenges, some researchers started to promote changes in the NS surface (or NS functionalization) in order to create adaptations according to the need (Azevedo & Gleize, 2018;Collodetti et al, 2014;Gu et al, 2016Gu et al, , 2018Huang & Wang, 2017;Monasterio et al, 2015;Perez et al, 2015). The functionalization of nanosilica is a chemical process that consists of adding new chemical functions to the NS surface.…”