Pervious concrete is a kind of porous and permeable material for pavements and slope protection projects, etc. In this paper, a kind of pervious concrete was prepared with Portland cement, silica fume (SF), polycarboxylate superplasticizer (SP), and limestone aggregates. The performance of concrete, such as its porosity, pore distribution, permeability coefficients, and mechanical properties, were studied through laboratory tests. The volumetric porosity was measured by the water displacement method, and the planar porosity and pore size distribution were determined using image processing technology. A permeameter with a transparent sidewall and an exact sidewall sealing method were used to measure the permeability coefficients accurately. The results show that the segregation index and flow values of pastes increased with the increase of SP and water cement ratio (W/C). The measured porosity (volumetric porosity and planar porosity) of pervious concrete with a single-size aggregate was closer to the design porosity than that with the blended aggregate. Compared with the design porosity selected in this study, aggregate size was the main factor influencing the pore distribution of pervious concrete. The standard deviation of the permeability coefficient was less than 0.03 under different hydraulic gradients. It was found that the relationships between the permeability coefficient and volumetric porosity (or effective pore size d₅₀) approximately obey polynomial function. Based on the test results, the optimized parameters were suggested for practical engineering: W/C of 0.26–0.30; 0.5% SP content; 5% SF content; 15–21% design porosity; and aggregate sizes of 4.75–9.5 mm and 9.5–16 mm.

Soil Rock Mixture (SRM) is often regarded as a problematic geological feature during geotechnical engineering projects, which is commonly reinforced by grouting methods. In this study, the mechanical behavior of grouted SRM is investigated. Laboratory experiments are carried out to study the fundamental penetration mechanism and distribution regularities of grout vein during grouting in SRM and investigate the influence of grouting reinforcement on the strength of SRM. The SRM material used in the experiment is prepared by mixing soil and gravel at different ratios. The grout veins are excavated after solidification to observe and categorize their typical distribution patterns and analyze the influence from rock blocks. Then, uniaxial compressive strength tests are conducted on the test samples of grouted SRM. Based on the experimental results, a theoretical model is proposed that considers the influence of block proportion, block count, grouting volume, and grout vein distribution. Finally, an evaluation method for the strength of grouted SRM which can reasonably estimate the strength of grouted SRM is proposed.