Experimental Study on the Strength and Hydration Products of Cement Mortar with Hybrid Recycled Powders Based Industrial-Construction Residue Cement Stabilization of Crushed Aggregate

Abstract

The strength-formation mechanism for industrial-construction residue cement stabilization of crushed aggregate (IRCSCA) is not clear. To expand the application range for recycled micro-powders in road engineering, the dosages of eco-friendly hybrid recycled powders (HRPs) with different proportions of RBP and RCP affecting the strengths of cement-fly ash mortar at different ages, and the strength-formation mechanism, were studied with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the early strength of the mortar was 2.62 times higher than that of the reference specimen when a 3/2 mass ratio of brick powder and concrete powder was mixed to form the HRP and replace some of the cement. With increasing HRP content substituted for fly ash, the strength of the cement mortar first increased and then decreased. When the HRP content was 35%, the compressive strength of the mortar was 1.56 times higher than that of the reference specimen, and the flexural strength was 1.51 times higher; XRD and SEM studies of the hydrated cement mixed with HRP showed that the amount of CH in the cement paste was reduced by the pozzolanic reaction of HRP at later hydration ages, and it was very useful in improving the compactness of the mortar. The XRD spectrum of the cement paste made with HRP indicated that the CH crystal plane orientation index R, with a diffraction angle peak of approximately 34.0, was consistent with the cement slurry strength evolution law, and this research provides a reference for the application of HRP to produce IRCSCA.

Effects of Layered Double Hydroxide Nanosheets with Different Cations on the Compressive Strength of Cement Composites

“…These patterns were used to analyze the structure of the cement hydration products, especially the crystalline calcium hydroxide (CH), which appeared at 2θ = 18.19°, 34.21°, 47.19°, and 51.01°. , The diffraction peaks of CH on the crystal faces (001) and (101) appeared at 18.19° and 34.21°, respectively. The crystal growth kinetics of the Portland stone in hydrated cement pastes was shown by the biaxial columnar model. , The R orientation index (or the R index) is 1.35 times the ratio of the peak intensities at 001 and 101 of the XRD pattern, which can be expressed as follows: where R is the crystal orientation index, I 001 is the peak intensity of the 001 interface, and I 101 is the peak intensity of the 101 interface.…”

“…The crystal growth kinetics of the Portland stone in hydrated cement pastes was shown by the biaxial columnar model. 32,33 The R orientation index (or the R index) is 1.35 times the ratio of the peak intensities at 001 and 101 of the XRD pattern, which can be expressed as follows:…”

“…The crystal growth kinetics of the Portland stone in hydrated cement pastes was shown by the biaxial columnar model. 32,33 The R orientation index (or the R index) is 1.35 times the ratio of the peak intensities at 001 and 101 of the XRD pattern, which can be expressed as follows: (1) where R is the crystal orientation index, I 001 is the peak intensity of the 001 interface, and I 101 is the peak intensity of the 101 interface.…”

Investigation of Mechanical and Shrinkage Performance for Large-Size Cement-Stabilized Aggregates

“…In this study, the gradation design for LSCSM was conducted based on the Bailey method. The separation sieve sizes for coarse and fine aggregates are determined according to Equation (2).…”

“…Semi-rigid base materials are widely utilized across various highway grades in China, owing to their commendable strength, stiffness, overall performance, and cost-effectiveness [ 1 , 2 ]. Nevertheless, asphalt pavements situated on semi-rigid base layers often face issues, prominently cracking.…”