Sulphoaluminate cement (SAC) is considered a low-carbon and energy-saving cementitious material, compared with ordinary Portland cement. However, the stabilization efficiency and improvement measures of SAC for dredged sediment (DS) are still unclear. This study used SAC as stabilizer for DS with high water content, and nanoparticles including nano-SiO2 (NS), nano-MgO (NM) and nanoAl2O3 (NA) were incorporated as nano-modifiers. Unconfined compressive strength (UCS) tests were carried out to evaluate the strength development of SAC-stabilized DS (SDS) and nano-modified SDS considering multiple influencing factors. Furthermore, the micro- mechanisms characterizing the strength development of SDS and nano-modified SDS were clarified and discussed based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests. The results present that increasing SAC content or decreasing water content can obviously enhance the strength gaining of SDS, while the strength reduction also occurred. Incorporating suitable nanoparticles could significantly improve the strength gaining and simultaneously avoid the strength reduction of SDS. The optimum content of single NS, NM and NA was respectively 4 %, 6 % and 6 %. Composite nanoparticles containing two types of nanoparticles also exhibit positive effect on the strength gaining of SDS, and the optimum mass ratios of NS-NM, NS-NA and NM-NA were respectively 3:7, 1:9 and 5:5. By comparison, adding 6 % NA to SDS achieved the highest strength gaining. The hydration product ettringite was mainly responsible for the strength development of SDS and nano-modified SDS, and incorporating nanoparticles especially NA contributed to the formation of a tighter structure with stronger cementation inside nano-modified SDS. A conceptual model was proposed to characterize the micro-mechanism of strength development in nano-modified SDS. (c) 2024 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY- NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The influence of curing temperature on the strength development of cement-stabilized mud has been well documented in terms of strength-increase rate and ultimate strength. However, the strength development model is not mature for the extremely early stages. In addition, there is a lack of studies on quality control methods based on early-stage strength development. This paper presents a strength model for cement-stabilized mud to address these gaps, considering various curing temperatures and early-stage behaviors. In this study, a series of laboratory experiments was conducted on two types of muds treated with Portland blast furnace cement and ordinary Portland cement under four different temperatures. The results indicate that elevated temperatures expedite strength development and lead to higher long-term strength. The proposed model, which combines a three-step conversion process and a hyperbolic model at the reference temperature, enables accurate estimate of the strength development for cement-treated mud with any proportions cured under various temperatures. With this model, a practical early quality control method is introduced for applying cement-stabilized mud in field projects. The back-analysis parameters obtained from a 36-h investigation at temperature of 60 degrees C demonstrated a sufficient accuracy in predicting strength levels in practical applications. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).