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• Flexural tensile strengths calculated with tensile and compressive differences are reduced by nearly 20 % when compared to those calculated without tensile and compressive differences. • A power function decay model of the tension–compression moduli of cement stabilized macadam was established in the four-point bending fatigue test. • The fatigue damage model of cement stabilized macadam was established and its accuracy was verified. Cement stabilized macadam (CSM) is a mixture created by combining cement as a binding material, water, and various particle sizes of minerals. The cement stabilized macadam material exhibits different moduli in tension and compression due to both its mechanical properties and the mechanical response in the asphalt pavement structure. To explore the strength, modulus and fatigue damage characteristics of CSM under different tensile and compressive modulus, this paper carried out the research. The calculation formulas for flexural tensile strength and tension–compression modulus were derived based on the difference in tension–compression modulus. A four-point bending strength test of CSM was carried out. Four-point bending fatigue tests with varying stress ratios were performed. It reveals deterioration laws of tension–compression modulus during fatigue process. The double logarithmic fatigue equation of CSM, as well as its nonlinear fatigue damage evolution equation, are established based on fatigue life results. The results of an analytical solution for fatigue life of rectangular section beams based on damage mechanics were obtained and compared to the results of four-point bending fatigue tests. The results reveal that the modulus of CSM differs in tension and compression. The calculated flexural tensile strength with the tension and compression difference is nearly 20 % lower than without the difference. The calculation approach that does not account for the difference in tension and compression overestimates the flexural tensile strength of CSM. The tension–compression moduli of CSM exhibit a power function decay law in the four-point bending fatigue processes. In the first stage, the dynamic modulus decays at a steady rate, accounting for 90 % of total fatigue life. The second stage in the life ratio of 0.9 occurs when the decay rate of the modulus rapidly increases and enters the stage of sharp decay. Based on the results of the four-point bending test, the modulus decay model was created. The decay parameter m has an exponential relationship with the stress ratio. The relative errors between the mean values of fatigue life tests and the predicted values of the analytical solutions range from 10.8 to 30.6 percent. The established fatigue damage equation for CSM can better reflect its fatigue damage evolution law. The research findings have great significance to solve the determination of pavement materials parameters based on the difference in tension and compression modulus. It also has a specific reference value for asphalt pavement design theory and calculation method when the varied modulus of tension and compression are considered. [ABSTRACT FROM AUTHOR]

• High alkali dosages lead to obvious reduction in flexural strength after 7 days. • High moduli contribute to rapid setting and high compressive strength. • Increasing curing time improves resistance to chloride penetration. • Low alkali dosages provide continuous development in strength after 28 days. Cement industry has become one of important sources of greenhouse gas emission. Compared with the cement, alkali activated slag (AAS) possesses comparable mechanical properties and lower carbon emission during its production. It can thus be employed as an alternative binder for low-carbon construction. This paper investigated the effect of alkali contents, moduli, and curing time on flexural strength, compressive strength, drying shrinkage, setting time, and resistance to chloride penetration of AAS. Alkali contents ranging from 2% to 6%, moduli of 0.6, 0.9, and 1.2, and curing time of 7, 28, 90 and 180 days were adopted in the test. Test results have shown that high alkali contents shorten setting and accelerate development of compressive strength, but cause large drying shrinkage, deterioration in flexural strength and resistance to chloride penetration of AAS. Alkali contents ranging from 3% to 4% in AAS can achieve the setting time, flexural and compressive strength comparable to cement. Increasing moduli can accelerate setting, improve compressive strength and lower chloride penetrability, but increase drying shrinkage and reduce flexural strength of AAS. Continuous curing after 28 days can significantly improve flexural strength, compressive strength and resistance to chloride penetration of AAS mortar with alkali contents of 2–3%. Using 28-day compressive strength as an index for classification will underestimate the AAS with low alkali contents. Analytical models considering effect of alkali contents and moduli are proposed to predict relationships between flexural strength and compressive strength of AAS mortar and achieve a good correlation with experimental results. [ABSTRACT FROM AUTHOR]

• Slant shear apparatus developed for testing asphalt concrete. • Shear tests conducted at different temperatures and shear strain rates. • Time-temperature superposition principle is confirmed. • Shear modulus and strength values to be used for different loading conditions. Asphalt concrete is a viscoelastoplastic material and its behavior depends on temperature and time. Asphalt concrete used as impervious core in embankment dams is subjected to different loading conditions at different temperatures. A shear apparatus is described and used to investigate the stress-strain-strength behavior of asphalt concrete by carrying out shear tests at different temperatures and shear strain rates. The domains of shear modulus and shear strength values of asphalt concrete are established by applying the time-temperature superposition principle. Shear modulus and shear strength values of asphalt concrete for different loading conditions are compared. The documented behavior can be used in the design of the asphalt core in embankment dams. [ABSTRACT FROM AUTHOR]