Effect of Aggregate Size and Water/Cement on Compressive Strength and Physiological Performance of Planting Concrete

Abstract

Planting concrete, an eco-friendly concrete in which plants can grow directly, has been widely used in roof greening and the slopes of rivers. Porosity and compressive strength are important indicators for evaluating the properties of planting concrete. By preparing planting concrete with different aggregate gradations (10–30 mm, 20–40 mm) and water–cement ratios (0.25, 0.27, 0.29, 0.31, 0.33), the effect of aggregate gradation and water–cement ratio on the porosity and compressive strength of the planting concrete was analyzed, the intrinsic relationship between aggregate gradation and plane pore parameters was studied, the strength growth pattern and microscopic strengthening mechanism were studied, the relationship between porosity and compressive strength of the planting concrete were explored, and a tall fescue planting experiment was carried out to evaluate the plantation performance of the planting concrete. The results show that under the same conditions of water–cement ratio, the smaller the particle size of the aggregate, the smaller the porosity of the plane, and the denser the structure. The average diameter of the planting concrete shows an exponential relationship with the porosity of plane. The early growth of the compressive strength of the planting concrete is rapid; the compressive strength has a linear relationship at the ages of 7 days and 28 days. Compared to polynomial and logarithmic functions, the exponential function gives a better insight into the relationship between the porosity and compressive strength of the planting concrete. Tall fescue seeds germinate and grow well; height, cover, and leaf rootstock and element content of plants can be used as indicators to assess the performance of vegetated concrete planting.

Enhancing the Mechanical Properties and Water Permeability of Pervious Planting Concrete: A Study on Additives and Plant Growth

“…The results showed that the compressive strength of the PPC prepared with 10~30 mm aggregate was slightly lower than that prepared with 20~40 mm aggregate. There was no obvious linear relationship between mechanical properties and W/B, and there was an optimal W/B in different mix ratios [14]. Huang Yamei et al compared the compressive strength of PPC prepared by aggregate with three different sizes of 5~20 mm, 16~31.5 mm and 20~40 mm.…”

Influencing Factors of Porosity and Strength of Plant-Growing Concrete

“…Numerous experiments have extensively investigated the correlation between porosity and strength in diverse porous materials [ 30 ]. Hasselmann et al [ 31 ] proposed a polynomial equation that can be applied to describe the correlation between porosity and strength in materials.…”

Research and Application Progress of Vegetation Porous Concrete

“…Therefore, the flowability of the paste in vegetation porous concrete is crucial for ensuring the uniformity, workability, and fillability of the material during construction. Several factors influence the flowability of the paste in vegetation porous concrete, including the water-cement ratio [32,64], additives [65], cement material quality [66], equipment, temperature, and environmental conditions [67]. The combined effect of these factors determines the flow performance of the paste.…”

“…Additionally, larger aggregate particle sizes result in tighter pore connectivity and a sparser structure. Chen [32], in order to analyze the surface porosity of vegetation concrete, employed a scalpel to section cubic standard specimens into layers. Digital photographs of the concrete sections were captured, and subsequent image processing involved equalization and grayscale conversion, as shown in Figure 5a.…”