Enhancement technologies of recycled aggregate – Enhancement mechanism, influencing factors, improvement effects, technical difficulties, life cycle assessment

Synergistic enhancement effect of recycled fine powder (RFP) cement paste and carbonation on recycled aggregates performances and its mechanism

Pore characteristics of pervious concrete and their influence on permeability attributes

https://depositonce.tu-berlin.de/bitstream/11303/12575/3/chung_etal_2021.pdf

Effect of different expanded aggregates on durability-related characteristics of lightweight aggregate concrete

Three silanes with different alkyl chain lengths were incorporated into PII 52.5 ordinary Portland cement to investigate their effects on cement hydration and mechanical development. The micro-mechanism of hydration process and hydrated products were well studied using Calorimeter, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Thermal gravimetric-Differential scanning calorimetry (TG-DSC). Results demonstrated that different alkylsilanes had diverse effects on cement hydration. In general, the shorter the alkyl chain length, the stronger the retardation. Furthermore, the porosity change due to the silane incorporated could be another reason for the decrease of the mechanical properties. Additionally, SEM images show that there are some fiber-like needle products formed on the surface of hydrated cement substrate. According to EDS analysis, they are likely composed of 2,4,4-trimethyl pentyl triethoxysilane (S1) and n-dodecyl triethoxysilane (S3), which might be produced from the reaction between calcium hydroxide and silane. In terms of water absorption reduction, S1 shows the lowest water uptake, which benefits from the branched structure in alkyl group of S1.

Study on alkylsilane-incorporated cement composites: Hydration mechanism and mechanical properties effects

Improvement in freeze-thaw durability of recycled aggregate permeable concrete with silane modification

A novel method to predict the mesostructure and performance of pervious concrete

The invention relates to the technical field of concrete, in particular to a modified recycled aggregate and a preparation method thereof and pervious concrete and a preparation method thereof. The preparation method of the modified recycled aggregate provided by the invention comprises the following steps: putting the recycled aggregate into an aqueous emulsion of methyltriethoxysilane, and modifying to obtain the modified recycled aggregate. The modified recycled aggregate provided by the invention is low in water absorption rate, when the modified recycled aggregate prepared by the method is used as an aggregate to prepare the pervious concrete, due to the fact that the surface of the modified recycled aggregate is provided with ae silane film with the hydrophobic effect, the situationthat the local water-cement ratio is increased due to the fact that water in cement paste is gathered to the surface of the aggregate can be avoided, a concrete interface transition area is more compact, and the frost resistance and strength of the pervious concrete are improved.

Modified recycled aggregate and preparation method thereof, and pervious concrete and preparation method thereof

The present invention discloses a performance prediction method and system of pervious concrete based on a meso-structure reconstruction model The method includes: obtaining a tomographic image of a coarse aggregate; extracting a coarse aggregate distribution region in the tomographic image of the coarse aggregate; calculating a maximum thickness of a coating; adding a cement-based coating with a preset thickness to the surface of the coarse aggregate in the coarse aggregate distribution region by a morphological operation method, to obtain a coating-added image; three-dimensionally reconstructing the coating-added image by a three-dimensional reconstruction method, to obtain a three-dimensional model of the pervious concrete; extracting a pore distribution region in the coating-added image; three-dimensionally reconstructing the pore distribution region by a three-dimensional reconstruction method, to obtain a three-dimensional model of a pore; and predicting a performance parameter of the pervious concrete corresponding to the three-dimensional model of the pervious concrete

Shen Mingming

Papers

Improvement in freeze-thaw durability of recycled aggregate permeable concrete with silane modification

A novel method to predict the mesostructure and performance of pervious concrete

Modified recycled aggregate and preparation method thereof, and pervious concrete and preparation method thereof

Performance Prediction Method And System Of Pervious Concrete Based On Meso-Structure Reconstruction Model