This study analyzes the mechanical properties of high ductility concrete (HDC) under different ambient temperatures to provide a parameter basis for the design of HDC bridge deck link slabs. Five temperatures (−30, 0, 20, 40, and 60 °C) were designed to investigate the compressive, tensile, and flexural properties of HDC after temperature treatment and analyze the pore structure. The results show that, compared with the HDC performance at room temperature (20 °C), the compressive strength, ultimate tensile strength, and flexural strength decreased after treatment at low temperatures (−30 and 0 °C), while the strength increased after treatment at high temperatures (40 and 60 °C). After experiencing low- and high-temperature treatments, the ultimate tensile strain and ultimate deflection of the HDC increased. The tensile and flexural failures of the HDC exhibited multiple cracking, and the stress–strain/deflection curve showed a strain/deflection hardening stage. The tensile constitutive relationship can be simplified as a bilinear two-stage relationship. As the temperature increased, the porosity of harmless and less harmful pores in HDC gradually increased, while the porosity of harmful and more harmful pores gradually decreased, resulting in an increase in HDC strength. Based on the influence of temperature on HDC properties, design parameters for the HDC bridge deck link slab structure are proposed.

To investigate the effect of water-to-binder ratio and fly ash content on the properties of bendable concrete, we prepared four samples of different strength grades with water-to-binder ratios of 0.25 and 0.30 and fly ash contents of 60% and 80%. The effects of water-to-binder ratio and fly ash content on the compressive strength, flexural strength, elastic modulus, fracture toughness, and uniaxial tensile deformation of the samples were investigated. The results show that the strength of bendable concrete can be varied by varying the water-to-binder ratio and fly ash content. Water-to-binder ratio and fly ash content showed almost the same effect on fracture toughness, whereas fly ash content exhibited a greater effect on elastic modulus. With an increase in water-to-binder ratio and fly ash content of concrete, the initial crack stress and tensile strength decreased and the ultimate tensile strain increased, but the change of water-to-binder ratio showed a more significant effect on the ultimate tensile strain.

The effect of cellulose fiber on the long-term compressive creep performance of concrete was clarified. For this, the long-term compressive creep properties of four cellulose fiber reinforced concrete (CFRC) groups with contents of 0, 0.9 kg/m³, 1.1 kg/m³, and 1.3 kg/m³ were investigated using a spring creep tester. Loading ages of 7 days, 14 days, and 28 days, and a loading stress ratio of 0.40 were employed. Furthermore, the creep model of CFRC was established. The results revealed that the creep of concrete at three loading ages decreases by 16%, 12%, and 17%, respectively, after adding cellulose fiber to the concrete. With increasing loading age, the difference of creep degree of CFRC with different cellulose fiber content decreased gradually. Furthermore, the range of specific creep decreased from 8 × 10⁻⁶ / MPa for a 7 day loading age to 2 × 10⁻⁶ / MPa for a 28 day loading age. The change regulation of CFRC creep coefficient was similar to that of the specific creep. The influence of the cellulose fiber on the creep performance of the concrete was reflected in two aspects. On the one hand, the internal curing effect of cellulose fiber can optimize the microstructure of concrete and reduce the creep deformation. On the other hand, the fiber increases the water migration channel and defects of interface transition zone, which will increase the creep deformation. The power exponential function model for CFRC creep provided a good description of the relationship between creep and loading age and holding time. This model can be used to predict the long-term creep of CFRC under different loading ages.

The influence of polyvinyl alcohol (PVA) fiber volume fraction and fly ash content on the creep behavior of high ductility cementitious composites (HDCC) under compression was investigated. For this investigation, the creep behavior of four HDCC groups with cube compressive strength of 30–50 MPa, PVA fiber volume fraction of 1.5% and 2.0%, and fly ash content of 60% and 80% at 7 d and 28 d loading periods, respectively, were evaluated. A compressive creep model, which reflects the loading age and holding time, was established. The results revealed that when the load was applied at 7 d and 28 d, and then maintained for 245 d, the specific creep of HDCC ranged from 95×10-6/ MPa to 165×10-6/ MPa and from 59×10-6/ MPa to 135 × 10−6/ MPa, respectively. The corresponding creep coefficients ranged from 1.48 to 2.25 and from 1.10 to 1.94, respectively. The PVA fiber volume fraction and fly ash content were the main factors affecting the specific creep of HDCC, which increased with increasing fiber fraction and fly ash content. Under short-term loading, the fiber volume fraction played a leading role in the specific creep, and the fly ash content played the leading role during long-term loading. Furthermore, the specific creep and creep coefficient decreased significantly with increasing loading age. The classical creep model described by a power exponent function is suitable for HDCC.

To prepare high-performance pervious concrete with excellent mechanical properties and permeability, an orthogonal test method is used to investigate the effects of water-to-binder (W/B) ratio, grading of small size aggregates, and target continuous void content on the mechanical properties and permeability of pervious concrete. The results show that the W/B ratio and grading of small-size aggregates have negligible effects on compressive strength and permeability. The target continuous void content is the key parameter in determining the permeability of concrete. The compressive strength must be controlled within a certain range to ensure a certain range of permeability. Only one permeability parameter is suitable for pervious concrete mix design.