To reveal the mechanism of the influence of the curing temperature on the strength of lime activated fly ash-GGBS cured silt soil, the curing of dredged silt was carried out by using fly ash and GGBS as the curing agent and lime as the activator. Unconfined compressive strength (UCS) experiments were carried out, and the micro-analysis of the cured silt was carried out by experimental methods including scanning electron microscope (SEM) tests, X-ray diffraction (XRD), etc. to reveal the mechanism of the curing temperature on the dredged silt. According to the test results, the hydration reaction and pozzolanic reaction between lime-fly ash-GGBS and silt soil were promoted with the increase of the curing temperature. when the curing temperature of the sample reached 40 ℃, a large amount of gel products such as hydrated calcium aluminate (C–A–H) and hydrated calcium silicate (C–S–H) were generated, which enhanced the bonding force between soil particles and filled up the inter-particle pore space, thereby improving the UCS of the sample. The results of SEM confirmed that C–A–H and C–S–H were the main substances for the construction of cured silt skeleton. C–S–H and C–A–H were detected by XRD. The results of the study fill the gap in the effect of curing temperature on the direction of lime-activated fly ash-GGBS cured silt soil.

To explore the reaction mechanism of sludge, slag, lime, and fly ash in high temperature environments, the unconfined compressive strength (UCS) test was hereby implemented to study the effect on curing age, curing temperature, slag content and fly ash content about the strength of sludge. Scanning electron microscopy (SEM) was used to observe the microscopic composition of the substance, and X-ray diffraction (XRD) was used to analyze the mineral composition at the micro level to further disclose its reinforcement mechanism. The experimental results demonstrate the difference in the strength measured by different dosage of curing agent, and results indicate that the strength of high temperature curing sample was obviously higher than that of low temperature curing sample. When the curing temperature rises, the pozzolanic reaction and hydration reaction between materials are accelerated, and a certain amount of gel products are produced, playing a precipitation and bonding role between particles. The 28 days and 90 days strengths of the sludge samples with 20% fly ash and 80% slag dosing at 40°C were 1139 KPa and 1194 KPa, which were 1.4 and 1.1 times of that of pure cement solidified sludge. At 60°C, the strength of 14 days, 28 days and 90 days were 802 KPa, 1298 KPa and 1363 KPa, which were 1.1, 1.5 and 1.3 times of that of pure cement solidified sludge. Under the influence of an alkaline environment, the silicon-aluminum grid structure was interconnected into a denser network structure, and the compressive strength of lime-activated fly ash-slag was thus continuously enhanced. Affected by the high temperature, lime-activated fly ash-slag solidified sludge could significantly improve the middle and late strength of the sample. The research showed that the new solidification material can replace partly the concrete curing agent, thereby alleviating the carbon emission and environmental pollution problems arising from cement solidified sludge.

A composite material was developed using carbide slag, water glass, slag, and micron silicon to facilitate the use of industrial waste resources. The mechanical properties of dredge sludge (DS) were analyzed, considering different proportions of cement, organic debris, and carbide slag. The composition and microstructure of the hydration products were analyzed using the X-ray diffractometer (XRD), scanning electron microscopy (SEM), and thermogravimetric (TG) analysis. The results indicate that with a precursor content of 20%, a water glass content of 3%, and an increase in carbide slag content from 4% to 12%, the strength of the sample initially increases and subsequently drops at each age. With a carbide slag level of 8%, the combination of CaO in the slag and water glass stimulated the slag and micron silica, leading to the formation of gel substances such C-S-H and C-A-S-H. The soil particles exhibited increased density as a result of the cohesive properties of the gel products. Following a maintenance period of 28 days, the sample’s compressive strength rose to 2280 kPa. When the carbide slag level exceeds 8%, the presence of Ca(OH)₂ in the mixture leads to the formation of carbonates, such as calcite, during the carbonization process. The organic matter subsequently undergoes a reaction with the Ca(OH)₂ produced during the hydration of the mixture, leading to the formation of a highly soluble complex. As a result, only a limited quantity of calcium ions in the pore solution participate in the pozzolanic reaction, hence reducing the formation of gel reaction products such C-S-H.

Most current traffic safety evaluations using traffic conflict techniques are based on the principles of vehicle dynamics and kinematics. In these evaluations, a lack of consideration of the coupling mechanism among drivers, road users and the road environment leads to a large limitation in the practical application of such evaluations. In this paper, we firstly considered the driver characteristics in traffic conflicts and introduced the electric field model to establish the psychological field model of a driver in a conflict environment and to obtain the psychological field strength of the driver. Secondly, based on the classification criteria of traffic conflict severity, the psychological field strengths of drivers in different traffic conflict scenarios were categorized, and the range values of psychological field strengths of different severity levels were obtained. Finally, the analysis of the experimental results showed that the mean value and standard deviation of the drivers’ mental field strengths were the largest in the opposite-direction conflict, indicating the largest dispersion of the field strengths; in the construction conflict, the mean value and standard deviation of the drivers’ mental field strengths were the smallest, indicating the smallest dispersion of the field strengths.

As an essential component of sludge, soil organic matter is also the most energetic component of the sludge solid phase. However, the organic content of sludge reduces the engineering qualities of cement-cured sludge and restricts the cement curing reaction process. Humic acid (HA) was employed in tests conducted indoors to mimic the organic material naturally present in the waste sludge. The effect of different HA and cement dosages was investigated for the strength of the dredged sludge. The mechanism of the effect of HA on the strength of cement-solidified dredged sludge (CDS) was examined in conjunction with the findings of unconfined compression strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). (1)The overall unconfined compressive strength of CDS decreased after the addition of HA. (2) The strength of the HA sludge-cured body exhibits an increasing trend with the increase in cement input. The strength of sludge cured bodies with high HA content can be enhanced by correctly increasing the curing agent. (3) HA acts as a cement retarder, delaying hydration time by adhering to the surface of cement particles to form an adsorption coating. (4) As observed by SEM, the conversion of C-S-H to foil-like is hindered by HA in the silt, and its microscopic morphology changes with the change of HA content, which is manifested by the decrease of CDS intensity on a macroscopic scale.

To enhance the strength of solidified waste sludge, this study builds upon traditional cement-based sludge solidification methods and the waste-to-waste treatment principle. Cement, slag and fly ash were selected as solidifies, with water glass serving as an activator. The objective is to determine the optimal raw material proportions for solidified sludge under composite activation. The strength and microstructure of the cured samples were investigated by unconfined compressive strength (UCS), X-ray diffraction (XRD) and thermogravimetric (TG) experiments. Taking the single-doped cement sample as the control group, the internal relationship between the amount of raw materials and the UCS of the sludge was explored, which provided a theoretical basis for optimizing the mix design of the sludge. The results demonstrate that when the ratio of cement: slag: fly ash is 15: 10: 5, the optimal dosage of water glass is 7%. Water glass provides a good alkaline environment for the composite system, which effectively promotes the hydration reaction and pozzolanic reaction of cement, slag and fly ash. The generated hydration products make the internal structure of solidified sludge more compact, thus significantly improving the strength of solidified sludge.