One-Part Plastic Formable Inorganic Coating Obtain from Alkali-Activated Slag /Starch(CMS) Hybrid Composites

Abstract

Coating technology can be applied to decorate building constructions. Alkali-activated materials (AAM) are promising green and durable inorganic binders which show potential for development as innovative coating. In the paper, the possibility of using AAM composited with starch (CMS) as a novel plastic formable inorganic coating for decorating in building was investigated. The rheological properties, including plastic viscosity, yield stress, and thixotropy were considered to be critical properties to obtain the working requirements. Four different mixtures were systematically investigated to obtain the optimum formulation, and then were used to study their hardened properties, such as mechanical strengths (compressive, flexural, and adhesive strength), drying shrinkage, cracking behavior, and microstructure. Study results found that CMS could quickly and efficiently be hydrolyzed in an alkaline solution to produce organic plastic gel which filled in AAM paste, leading to the significant improvement of coating consistency, plastic viscosity, and thixotropy. The optimum coating composited with 15.40 wt% CMS shows a relatively stable rheological development, the setting time sufficient at higher than 4 h. Furthermore, CMS shows a significant positive effect on the cracking and shrinkage control due to padding effect and water retention of CMS, which results in no visible cracks on the coating surface. Although the mechanical strength development is relatively lower than that of plain AAM, its value, adhesive strength 2.11 MPa, compressive strength 55.09 MPa, and flexural strength 8.06 MPa highly meet the requirements of a relevant standard.

Inhibition of Efflorescence in Na-Based Geopolymer Inorganic Coating

“…However, it should be noted that high mechanical strength is not always a good thing, for example, sometimes high bonding strength of the geopolymer coating may cause peeling; the geopolymer coating and the putty surface will pull out of the wall together. 23 The 28 days' compressive strength of M4 is 43 MPa, which is very close to the OPC 425 cement. This strength value can provide enough high-strength requirements for coating use.…”

“…On the other hand, mica definitely diluted the geopolymer binder content due to the large use in this study. However, it should be noted that high mechanical strength is not always a good thing, for example, sometimes high bonding strength of the geopolymer coating may cause peeling; the geopolymer coating and the putty surface will pull out of the wall together . The 28 days’ compressive strength of M4 is 43 MPa, which is very close to the OPC 425 cement.…”

“…The 28 days’ compressive strength of M4 is 43 MPa, which is very close to the OPC 425 cement. This strength value can provide enough high-strength requirements for coating use …”

“…This strength value can provide enough high-strength requirements for coating use. 23 3.2. Water Absorption and Leachate Test.…”

Preparation, Surface Characterization, and Water Resistance of Silicate and Sol-Silicate Inorganic–Organic Hybrid Dispersion Coatings for Wood

“…Concrete is a well-studied example [38][39][40]. Large continuous macroscopically visible cracks were reported in activated fly ash slag/sodium silicate coatings brushed on concrete substrates and were reduced by a carboxymethyl starch admixture acting by retaining water in the coatings during curing [41]. Organosilanes such as MTMS and HDTMS are used in the preparation of crack-free and flexible silica aerogels [42].…”