Pervious concrete is considered to be an advanced pavement material in terms of the environmental benefits arising from its basic feature—high water-permeability. This paper presents the results of experimental work that is aimed at testing technically important properties of pervious concrete prepared with three different water-to-cement ratios. The following properties of pervious concrete were tested—compressive and splitting tensile strength, unit weight at dry conditions, void content, and permeability. The mix proportions were expected to have the same volume of cement paste, and, to obtain the same 20% void content for all of the samples. The results show that changes of water-to-cement ratio from 0.35 to 0.25 caused only slight differences in strength characteristics. Arising tendency was found in the case of compressive strength and a decreasing tendency in the case of splitting tensile strength. The hydraulic conductivity ranged from 10.2 mm/s to 7.5 mm/s. The values of both the unit weight and void content were also analysed to compare the theoretical (calculated) values and real experiment results. A fairly good agreement was reached in the case of mixtures with 0.35 and 0.30 water-to-cement ratios, while minor differences were found in the case of 0.25 ratio. Finally, a very tight correlation was found between void content, hydraulic conductivity, and compressive strength.

Pervious concrete is characterized by its open-void structure, which gives it a number of specific properties and allows specific applications, including pervious pavements, residential roads, alleys, sidewalks, parking lots, patios, and so on. Permeable areas are extremely important for the creation of sustainable cities in terms of the water cycle. Due to its high void content and low cement/mortar content, pervious concrete generally may have significantly reduced strength when compared with conventional concrete. That is why a wide range of research activities is devoted to the balance between acceptable void content, strength, as well as other significant properties. Knowledge of the relationships between the individual properties is very important for understanding this specific material. In this paper, a wide range of 38 different composition variants has been tested to determine the dependencies between the essential properties of pervious concrete. The variables related to the type of aggregate, maximum grain size, the grain-size composition, the amount of binder, and the kind (composition) of binder. The dependencies reported in the article are defined with high reliability R² ranging from 0.75 to 0.95. On the basis of the dependencies thus determined, it can be predicted that a density of min. 1740 kg/m³ must be reached to meet the requirement of min. 10 MPa for nonpavement applications, while a density of min. 1960 kg/m³ must be achieved to meet min. 20 MPa for pavement applications. The criteria of the void ratio for pavement applications can be set at 20 ± 3%, while the criteria for nonpavement applications can be set at 28 ± 6%.

Pervious concrete is considered to be a sustainable pavement material due to high water permeability. The experiment presented in this paper was aimed at study the influence of water to cement ratio on both the compressive and splitting tensile strength of pervious concrete. Typically, less water content in concrete mixture leads to less porosity of cement paste and thus it provides desirable mechanical properties. In case of conventional dense concrete, the lower is the water to cement ratio, the higher or better is the strength, density and durability of concrete. This behaviour is not quite clear in case of pervious concrete because of low amount of cement paste present. Results of compressive and splitting tensile strength of pervious concrete are discussed in the paper while taking into account values measured after 2 and 28 days of hardening and variations in water to cement ratio. The results showed that changes of water to cement ratio from 0.25 to 0.35 caused only slight differences in strength characteristics, and this applied to both types of tested strength.

Article contains experiment investigating influence of partial cement replacement by zeolite on consistency of fresh concrete, early compressive strength development and temperature development in early stages of curing. Four concrete mixture compositions were tested – containing zeolite in 0%, 5%, 10% and 15% of binder weight. Consistency was tested by flow table test in 5 minutes and 30 minutes after mixing of fresh concrete. Compressive strength and temperature gain were tested after 12, 16, 20 and 24 hours of curing. Results showed significant influence of zeolite on consistency of fresh concrete while compressive strength results were still in the acceptable range.

The article deals with cement supplementary materials based on ground granulated blast furnace slag and zeolite. Purpose of the experiment was to observe dependences (if they exist) between selected parameters (modulus of basicity, modulus of hydraulicity and initial setting time) and activity indexes, for easier and quicker way to determine or predict the activity index. Testing showed that moderate dependences between those parameters and activity indexes were observed. Results showed that prediction of activity indexes based on chemical composition is feasible.