The increasing demand for high-strength lightweight concrete (HSLWC) with excellent mechanical properties has inspired the development of nanomaterials in fundamentally solving brittleness and cracking. This work investigated the effects of graphene oxide (GO) on the mechanical properties and microstructure of HSLWC, including the workability, density, compressive strength in different curing regimes, splitting tensile strength, flexural strength, modulus of elasticity and scanning electron microscopy (SEM). Six groups of mixtures were mixed with GO aqueous solution at a dosage of 0.00%, 0.02%, 0.04%, 0.05%, 0.06%, and 0.08% by weight of cement, respectively, and dispersed by ultrasound for 30 min. The test results showed that adding a low volume of GO to the specimens could slightly increase the density, rationally reduce the slump, and significantly improve the mechanical properties. The maximum increase in compressive strength, splitting tensile strength, modulus of elasticity and flexural strength of HSLWC with GO at 28 days was by 24%, 17%, 15%, 20%, respectively, as compared with HSLWC without GO. Simultaneously, the SEM results showed that GO could not only fill nano-scale pores, but also regulate the formation and growth of flower-like crystals, which was an important factor for the further improvement of properties. The research results provided a potential new pathway to improve the mechanical properties of HSLWC.

All gibbon species (Primates: Hylobatidae) are facing high extinction risk due to habitat loss and hunting. The Hainan gibbonNomascus hainanusis the world’s most critically endangered primate, and one of the priority conservation actions identified is to establish artificial canopy corridors to reconnect fragmented forests. The effectiveness of artificial canopy bridge as a conservation tool for wild gibbons has not been widely tested, and the results are rarely published. We constructed the first canopy bridge for Hainan gibbon in 2015 to facilitate passage at a natural landslide; mountaineering-grade ropes were tied to sturdy trees with the help of professional tree climbers and a camera trap was installed to monitor wildlife usage. Hainan gibbon started using the rope bridge after 176 days, and usage frequency increased with time. All members in the gibbon group crossed the 15.8 m rope bridge except adult male. Climbing was the predominant locomotor mode followed by brachiation. This study highlights the use and value of rope bridges to connect forest gaps for wild gibbons living in fragmented forests. While restoring natural forest corridors should be a priority conservation intervention, artificial canopy bridges may be a useful short-term solution.

An effective pathway to achieve the sustainable development of resources and environmental protection is to utilize shale ceramsite (SC), which is processed from shale spoil to produce high-strength lightweight concrete (HSLWC). Furthermore, the urgent demand for better performance of HSLWC has stimulated active research on graphene oxide (GO) in strengthening mechanical properties and durability. This study was an effort to investigate the effect of different contents of GO on HSLWC manufactured from SC. For this purpose, six mixtures containing GO in the range of 0–0.08% (by weight of cement) were systematically designed to test the mechanical properties (compressive strength, flexural strength, and splitting tensile strength), durability (chloride penetration resistance, freezing–thawing resistance, and sulfate attack resistance), and microstructure. The experimental results showed that the optimum amount of 0.05% GO can maximize the compressive strength, flexural strength, and splitting tensile strength by 20.1%, 34.3%, and 24.2%, respectively, and exhibited excellent chloride penetration resistance, freezing–thawing resistance, and sulfate attack resistance. Note that when the addition of GO was relatively high, the performance improvement in HSLWC as attenuated instead. Therefore, based on the comprehensive analysis of microstructure, the optimal addition level of GO to achieve the best mechanical properties and durability of HSLWC is considered to be 0.05%. These findings can provide a new method for the use of SC in engineering.

With the ongoing global biodiversity crisis in the Anthropocene, it is critical to understand how to save endangered species to “bend the curve” of biodiversity decline. The Hainan gibbon (Nomascus hainanus) is a Critically Endangered species that is endemic to Hainan Island. We performed two synchronized total count surveys in Hainan Tropic Rain Forest National Park in November and December of 2020 and 2021 by locating gibbon groups from their morning calls and conducting detailed counts in all potential habitat fragments. We compared our findings with existing data to model the population trend, and analyzed the potential and realized reproductive potentials. We found 5 groups with a total of 33 gibbons in 2020 and 35 in 2021, including 4 and 6 solitary individuals respectively. This is an increase of 169% since 2003, when there were 13 individuals with 2 groups and 2 solitary individuals. Logistic and linear curves fitted the 2003-2021 population census data equally well. Although the population is growing, it has not realized its full reproductive potential (when all adult females give births at 24-month intervals), suggesting that external factors like available habitat, as well as nutritional, physiological, and behavioral factors may be limiting the population. The gibbon’s recovery demonstrates that establishing a nature reserve with regular patrols, banning logging, curbing poaching, and environmental education have been effective. Because the Hainan gibbon population is still extremely small, carefully planned conservation actions, including an ambitious forest restoration program, will be needed to ensure the species’ continued survival.

The excellent performance of graphene oxide (GO) in terms of mechanical properties and durability has stimulated its application potential in high-strength lightweight concrete (HSLWC). However, more attention needs to be paid to the long-term drying shrinkage of HSLWC. This work aims to investigate the compressive strength and drying shrinkage behavior of HSLWC incorporating low GO content (0.00–0.05%), focusing on the prediction and mechanism of drying shrinkage. Results indicate the following: (1) GO can acceptably reduce slump and significantly increase specific strength by 18.6%. (2) Drying shrinkage increased by 8.6% with the addition of GO. A modified ACI209 model with a GO content factor was demonstrated to have high accuracy based on the comparison of typical prediction models. (3) GO not only refines the pores but also forms flower-like crystals, which results in the increased drying shrinkage of HSLWC. These findings provide support for the prevention of cracking in HSLWC.

High-strength lightweight concrete (HSLWC) is increasingly needed in modern architectural structures. However, conventional HSLWC is brittle and has a low tensile strength. This study investigated the possibility of combining multiwalled carbon nanotubes (MWCNTs) with shale pottery sand (SPC) and shale ceramsite (SC) to improve the mechanical characteristics and microstructure of HSLWC. Workability, mechanical properties (compressive strength under different curing regimes, splitting tensile strength, modulus of elasticity, flexural strength, slump and density), and microstructure were assessed for six different MWCNT contents (0%, 0.02%, 0.05%, 0.1%, 0.15%, and 0.2%, by cement weight). The findings indicated that the slump decreases as the MWCNT concentration increases, whereas all the mixtures maintain densities within the lightweight concrete range. At a carbon nanotube content of 0.1%, the compressive strength, splitting tensile strength, elastic modulus, and flexural strength of the 28-day high-strength, low-density concrete increase by 25.34%, 31.25%, 22.83%, and 46.83%, respectively, compared with those of the concrete without MWCNTs. The optimal curing condition was determined to be 7 days. Furthermore, the incorporation of a superplasticizer and shrinkage-reducing admixture helps maintain the lightweight properties of the concrete while ensuring structural integrity. Scanning electron microscopy analysis revealed that carbon nanotubes effectively bridge microcracks, reinforce weak areas, and impede microcrack propagation. This synergistic approach of combining carbon nanotubes with SC and SPC represents a novel strategy for enhancing the performance of high-strength, low-density concrete, improving the mechanical properties of lightweight concrete, and optimizing the dispersion of carbon nanotubes, thereby facilitating broader technical applications.