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

Abstract

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. The best mechanical properties were observed for a fly ash-to-slag ratio of 1:2 (F10S20; i.e., 10% fly ash and 20% slag) and its compressive strength at different temperatures was higher than that of concrete, containing 30% fly ash (F30) or 30% slag (S30), but the flexural and splitting tensile strength was lower than S30. Further, as the temperature decreased, the fly ash concrete’s damaged layer thickness gradually increased. When the content of fly ash and slag were both 15% (F15S15), the damaged layer thickness was minimal at different low temperatures, especially at −30 °C, where the thickness was only 8.31 mm.

An Overview of Smart Materials and Technologies for Concrete Construction in Cold Weather

“…The use of SCMs, such as fly ash, slag, or silica fume, can improve the concrete's resistance to freezing and thawing cycles by increasing the water-binder ratio [165]. SCMs can thereby reduce the permeability of concrete and enhance its durability, making it less susceptible to frost damage and early freezing [166].…”

Research on the Mechanical Properties of Concrete under Low Temperatures

“…Longarini [12] indicates that using fly ash in the mix design for concrete leads to a significant improvement in fresh concrete properties. Zhang [13] indicate that fly ash concrete has higher strength under different low temperatures compared to concrete strength at room temperature, especially at −30 • C, followed by −40 • C, −10 • C, and −20 • C. Shi Xudong [14] have proven that the relative increase in the compressive strength of concrete is positively correlated with its strength grade. The higher the strength grade, the greater the strength increment; however, this increment becomes gradual and insignificant when the concrete strength grade reaches C50 and above [15].…”

Corrosion Activity of Stainless Steel SS430 and Carbon Steel B450C in a Sodium Silicate Modified Limestone-Portland Cement Extract

“…The two of the most common alternative types of cement include: (a) blended cement, in which PC is partially replaced by one or more supplementary cementitious materials (limestone, blast furnace slag, fly ash, calcinated clays, natural pozzolan, waste glass, etc.) [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]; and (b) alkali-activated cement (AAC), based on the reaction of a precursor (i.e., the supplementary cementitious materials referred above, limestone, etc.) and alkaline activators (alkali silicates and/or hydroxides) [ 11 ].…”