Experimental Study on the Application of Recycled Concrete Waste Powder in Alkali-Activated Foamed Concrete.

The alkali-activated cementitious material was prepared by partially replacing slag with recycled concrete powder (RCP). The influence of RCP substitution rates (10%, 20%, 30%, 40%, and 50% mass fraction) on the performance of alkali-activated slag-RCP-based (AASR) foamed concrete was studied. The fluidity, water absorption, softening coefficient, compressive strength, flexural strength, drying shrinkage, thermal conductivity, and frost resistance of AASR foamed concrete were studied.

Properties of Gangue Powder Modified Fly Ash-Based Geopolymer.

The environmental and economic problems caused by gangue accumulation continue to worsen. Therefore, the implementation of a cost-effective method for utilizing gangue resources is urgent. In this study, different gangue powder (GP) contents (0%, 10%, 20%, 30%, 40%, and 50%) for mechanical-thermal activation were used to modify a fly ash-based geopolymer (FAG).

Effect of Replacing Fine Aggregate with Fly Ash on the Performance of Mortar.

Natural river sand resources are facing depletion, and large-scale mining pollutes the environment and harms humans. To utilize fly ash fully, this study used low-grade fly ash as a substitute for natural river sand in mortar. This has great potential to alleviate the shortage of natural river sand resources, reduce pollution, and improve the utilization of solid waste resources.

Mechanical Properties and Damage Layer Thickness of Green Concrete under a Low-Temperature Environment.

To study the influence of mineral admixtures on concrete's mechanical properties after a low-temperature exposure, green concrete was prepared by mixing fly ash and slag at different replacement rates. By analysing the changes to concrete's mechanical properties and the damage layer thickness under different ambient temperatures (20, -10, -20, -30, and -40 °C), the change rule of concrete at low temperatures was explored. The results revealed that the compressive strength of concrete, containing either fly ash or slag, peaked at 30 °C; moreover, the slag concrete's flexural and splitting tensile strength peaked at -40 °C.

Preparation and Properties of Foam Concrete Incorporating Fly Ash.

Foam concrete is fire resistant and durable and has broad applicability as a building insulation material. However, cement has high energy consumption and causes pollution, necessitating an environment-friendly cementitious material to replace the cement used to prepare foam concrete. In this study, foam concrete was prepared through chemical foaming.

Effect of Equal Volume Replacement of Fine Aggregate with Fly Ash on Carbonation Resistance of Concrete.

Concrete is prepared by substituting an equal volume of fly ash for fine aggregate, and the effect of substitution rate on its carbonation resistance is studied. Using a rapid carbonation test, the distribution law of the internal pH value of concrete with fly ash as fine aggregate (CFA) along the carbonation depth under different substitution rates (10%, 20%, 30%, and 40%) after carbonation is studied and compared with the test results of phenolphthalein solution. Then, to further clarify the damage mechanism of fly ash replacing fine aggregate on concrete carbonation, the changes in the pore structure and micromorphology of CFA after carbonation are studied by means of mercury intrusion pressure and electron microscope scanning tests.