Influence of composite admixtures on the freezing resistance and pore structure characteristics of cemented sand and gravel

Abstract

CSG shows low freezing resistance due to its poor cementing properties, and adding admixtures is the main method to improve its freezing resistance. In this paper, experiments were designed based on the Taguchi method and on the freezing resistance and pore structure characteristics of CSG after adding admixtures. After 20 freeze-thaw cycles, the results showed that both the compressive strength and dynamic elastic modulus of CSG decreased. The area occupancy of more harmful pores (>200 nm) in the NMR test increased, and the fractal dimension of the pore structure in the SEM images also increased. Based on the above indicators, it was concluded that L9 (sodium dodecyl sulfate, graphene oxide, nanosilica powder, and water-reducing agent) has the best freezing resistance. Experiments were conducted on L9 to verify that L9 can significantly improve the freezing resistance of CSG materials under different water-binder ratios, sand ratios, and cement dosages.

New insights into the production of sustainable synthetic aggregates and their microstructural evaluation

“…The experimental investigation conducted by Xavier et al (28) on the ternary blended concrete system, which is rich in iron, was developed using the Taguchi method. Using the Taguchi approach, Guo et al (29) developed experiments to examine cemented sand and gravel's freezing resistance and pore struc- As shown in Table 3, the selection of parameters and their appropriate levels was decided from prior studies. In this research, the four design factors: Ordinary Portland cement content (%), GGBFS content (%), metakaolin content (%), and w/b ratio, were considered with three levels, which makes a maximum of nine trials.…”