Effect of Mortar Surplus Coefficient on the Mix Design and Performance of Granite Tunnel Slag Aggregate Concrete
Year: 2026
Type: article
Abstract: To facilitate the graded resource utilization of granite tunnel slag (GTS), the mix proportions of GTS aggregate concrete were optimized using the mortar surplus coefficient (MSC) as a mix-design parameter. Concrete mixtures with different MSC values were designed by adjusting the coarse-aggregate gradation and sand ratio. The relationships between MSC and workability, mechanical properties, early-age shrinkage, and cracking resistance were systematically investigated, with the observed performance variations interpreted as the coupled responses of MSC and the corresponding mix-design variables. The results show that relatively high aggregate packing densities were achieved when the mass ratios of 5–10 mm, 10–20 mm, and 16–31.5 mm coarse aggregates were 4:3:3 or 2:6:2. Concrete flowability generally increased with MSC, while early-age shrinkage showed an overall increasing tendency across the investigated mixtures. Within the investigated mixtures, an indicative MSC interval of 1.79–1.90 corresponded to a favorable balance between workability, compactness, and compressive strength. In addition, JP-262 (MSC = 1.82) exhibited improved cracking resistance compared to REF-172 (MSC = 1.67). However, at MSC = 2.01, the largest early-age shrinkage was observed, indicating that excessive mortar content may adversely affect volumetric stability. An MSC-based mix-proportion optimization method for GTS aggregate concrete is proposed, providing a theoretical basis and technical support for optimizing the overall performance of granite tunnel slag aggregate concrete and promoting the efficient resource utilization of tunnel slag.
Source: Buildings
Authors: Zongyao Li, Debo Wang, Chuan Huang, Xinping Li
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7221896558