Abstract
This paper investigated the effects of silane impregnation on the protective properties of alkali-activated slag (AAS) mortars. The surface silane impregnation on water absorption, contact angle, and penetration depth were examined. The related protective mechanism regarding silane impregnation was analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier infrared spectroscopy (FT-IR). The results showed that the surface of the AAS mortar after silane impregnation was transformed from hydrophilic to hydrophobic with an increased contact angle of 80° from 36° to 116°. And the water absorption was significantly decreased by 74.42% to 97.79%. The penetration depth of the two-layer coating was dramatically higher than that of the one-layer coating. The optimal coating method and dosage of silane were two-layer coating and 200 g/m2. In addition, silane impregnation formed a stable Si-O bond with AAS mortars through a hydrolytic condensation reaction and the −CH2CH3 group of the silane acted on the surface of the AAS mortars.
Highlights
Introduction e characteristics ofactivated slag (AAS), such as easy preparation, low energy consumption, solid waste utilization, and low cost, have made it known as an environmentally friendly “green material” in the past few decades, with great development potential [1, 2]
Previous researches on surface impregnation mainly studied the durability of carbonization resistance and chloride ion resistance and rarely analyzed it from the microscopic perspective. erefore, there is a need to conduct a systematic experimental investigation to evaluate the protection of silane impregnation on AAS mortars and provide reference for the protection of AAS mortars. e objective of this paper is to study the protection of silane impregnation on AAS mortar. e isobutyltriethoxysilane was used, and three different dosages (100, 200, and 300 g/m2) with two different coating methods of silane were utilized to coat the surface of the AAS mortars
Afterwards, water was sprayed onto the fracture surface of the test block as a hydrophobic indicator. e measurement of the depth of the area not wetted by water is the penetration depth of silane due to its hydrophobic property. 8–10 different locations were taken for measurement for each test specimen, and the average value was reported
Summary
E Ground Granulated Blast Furnace Slag (GGBFS) was purchased from China Fuyang Xinyuan Building Materials Co., Ltd. Materials. E Ground Granulated Blast Furnace Slag (GGBFS) was purchased from China Fuyang Xinyuan Building Materials Co., Ltd It is classified into S105 grade with an activity index greater than 105 according to GB/T 18046 [25]. E hydrolysis time of silane can be tested by monitoring its conductivity [26]. E test solution was a 5% silane solution prepared in a mixture of distilled water. The residual unsealed surfaces of the specimen were brushed with silane and were evenly brushed in the same direction for 8–10 times. E time interval between two-layer coatings was 6 hours to ensure that the silane applied in the first-layer coating was fully bonded to the mortar.
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