Mechanical Properties Of Porous Concrete Research Articles

Impact of Water Level Variation on Mechanical Properties of Porous Concrete

This paper investigates porous concrete and the influence of water level variations and porosity on the mechanical, physical, and hydraulic properties of porous concrete. The effect of different void percentages and various water levels on the properties of porous concrete was studied. Fabricated specimens with targeted porosities of 20% and 25% were subjected to a series of tests to evaluate their compressive strength, hydraulic conductivity (permeability), and porosity. The permeability of the specimens was assessed using a falling head permeameter to ensure effective water percolation. Porosity was quantified through a volumetric method, providing insights into void content. Both cubical and cylindrical specimens were used for all tests, along with compression tests under both air-dried and oven-dried conditions. The results showed that the maximum compressive strength occurred under oven-dried conditions for both cubical (7.05 MPa, 5.58 MPa) and cylindrical (8.36 MPa, 4.81 MPa) specimens, with 20% and 25% porosities, respectively. The compressive strength was found to be low in air-dried samples and increased with higher water levels, peaking at the 40% water level. Furthermore, the porosity exhibited a significant correlation with the reduction in density, affecting the mechanical properties. For the cylindrical and cubical samples, the dry density decreased by 16.03 kg/m3 and 20.85 kg/m3 and the permeability increased by 0.41 mm/s and 0.84 mm/s, respectively, for every 1% increase in porosity. The results showcased the effect of water level variation on porous concrete properties as well as its promising ability to infiltrate water. This promotes the development of sustainable pavement systems by minimizing surface runoff and aiding groundwater recharge.

Effects of specimen shape and size on the permeability and mechanical properties of porous concrete

Porous concrete, which is generally considered as an environment-friendly pavement, plays an important role in sponge city. However, measuring its strength and permeability with different specimen shapes and sizes has not been paid enough attention by the researchers. Therefore, the effects of the size and shape on the permeability and mechanical properties of porous concrete were investigated in this paper. Thus, two types of aggregates and three types of cement were selected to cast different mixtures in different molds (two sizes of cylindrical and cuboid specimens). All porous concrete specimens were tested to evaluate the influence of shape and size on the permeability of porous concrete firstly. Then the different cube and cuboid specimens were nominated to measure the compressive strength and flexural strength of porous concrete respectively. Two different sizes of cylindrical specimens were selected to test the compressive strength and splitting strength. The results show that porosity, aggregate size, aggregate type, cement grade could affect the strength of porous concrete. Moreover, the compressive strength, flexural strength, splitting strength of the porous concrete with two different sizes, and the compressive strength and splitting strength with different shapes are significantly different.

Using Waste Vermiculite and Dolomite as Eco-Friendly Additives for Improving the Performance of Porous Concrete

The present study investigated the applicability of waste vermiculite and dolomite as fine aggregate, known as appropriate mineral adsorbents to enhance the quality of urban runoff, for improving the mechanical properties of porous concrete. 180 samples were mixed by adding 5-30% vermiculite and dolomite, as fine aggregate, and combining them with ordinary sand; lime sand (combining of 5-15% of each). Results showed that although adding dolomite culminated in a minor reduction of permeability– average of about 30%-, the average of compressive strength was augmented by 120%. Results of compressive strength of dolomite samples were repeated in mixtures containing vermiculite (an increase of 57%). While exploiting vermiculite in high percentages (20, 25, and 30) resulted in an extensive decrease in the permeability (94%), it was improved to an acceptable level (about 40%) after using vermiculite in combination with ordinary sand (lime sand). All dolomite and improved vermiculite mixtures, after combining vermiculite with ordinary sand, had appropriate performance in draining storm-urban runoff; such that in the weakest case, stimulated storm runoffs with heights of 10, 20, 30 and 40 cm were completely drained only after 17, 36, 59 and 87 seconds, respectively. Also, using vermiculite resulted in reducing the concrete weight (about 100 kg). Generally, although a little reduction in the permeability was seen, but using waste vermiculite and dolomite improved the mechanical properties of porous concrete significantly.

Numerical Simulation of Dynamic Mechanical Properties of Porous Concrete Fabricated with the SAP

Numerical Simulation of Dynamic Mechanical Properties of Porous Concrete Fabricated with the SAP

English

English

ВЫСОКОПРОЧНЫЕ НЕАВТОКЛАВНЫЕ И МИКРОПОРИСТЫЕ АВТОКЛАВНЫЕ ГАЗОБЕТОНЫ

Приведены результаты исследования основных физико-механических свойств ячеистых бетонов на основе крупнотоннажных отходов металлургии. Установлен вид зависимости прочности бетонов ячеистой структуры от прочности материала матрицы. Представлены результаты исследования свойств микропористого газобетона.

ОСОБЕННОСТИ ТЕХНОЛОГИИ ПОЛУЧЕНИЯ КОНСТРУКЦИОННО-ТЕПЛОИЗОЛЯЦИОННЫХ ЯЧЕИСТЫХ БЕТОНОВ НА ОСНОВЕ НЕТРАДИЦИОННОГО СЫРЬЯ

It was found that the clay rocks unfinished stage mineral suitable as a raw material for thermal insulation materials construction-autoclaved. High activity of raw rock-forming minerals accelerate the synthesis of tumors and the formation of a rational connection cementitious microstructure that provides high physical and mechanical properties of porous concrete. At the same time by reducing the pressure and time of autoclaving and simplify technology possible reduction of energy production costs by 35%. 

Effects on the Physical and Mechanical Properties of Porous Concrete for Plant Growth of Blast Furnace Slag, Natural Jute Fiber, and Styrene Butadiene Latex Using a Dry Mixing Manufacturing Process.

To evaluate the effects of industrial by-products materials on the performance of porous concrete for plant growth, this study investigated the physical, strength, and freeze/thaw resistances of porous concrete for plant growth, prepared by replacing cement with blast furnace slag powder at 60% by weight, and replacing natural stone aggregates with coarse blast furnace slag aggregates at rates of 0%, 20%, 40%, 60% and 100% by weight. In addition, the effects of adding natural jute fiber and styrene butadiene (SB) latex to these concrete mixtures were evaluated. The void ratio, compressive strength, and freeze/thaw resistance of the samples were measured. With increasing replacement rate of blast furnace aggregates, addition of latex, and mixing of natural jute fiber the void ratio of the concrete was increased. Compressive strength decreased as the replacement rate of blast-furnace slag aggregates increased. The compressive strength decreased after 100 freeze/thaw cycles, regardless of the replacement rate of blast furnace slag aggregates or of the addition of natural jute fiber and latex. The addition of natural jute fiber and latex decreased the compressive strength after 100 freeze/thaw cycles. The test results indicate that the control mixture satisfied the target compressive strength of 10 MPa and the target void ratio of 25% at replacement rates of 0% and 20% for blast furnace aggregates, and that the mixtures containing latex satisfied the criteria up to an aggregate replacement rate of 60%. However, the mixtures containing natural jute fiber did not satisfy these criteria. The relationship between void ratio and residual compressive strength after 100 freeze/thaw cycles indicates that the control mixture and the mixtures containing jute fiber at aggregate replacement rates of 20% and 40% satisfied the target void ratio of 25% and the target residual compressive strength of over 80% after 100 freeze/thaw cycles. The mixtures containing latex and aggregate replacement rates up to 60% satisfied the target void ratio and compressive strength.

The Mechanical Properties of Porous Concrete using Recycled Asphalt Aggregate

In this study, it is analyzed that mechanical properties and required strength of porous concrete according to the mixing ratio of cement, fine aggregate, and water/cement ratio in order to evaluate mechanical properties of porous concrete using recycled asphalt aggregate. Recycled asphalt aggregates of 13 mm were used without modification of aggregate grading to extend porous concrete application. The water/concrete ratio was poor mix and the range of compressive strength was 18.2 to 19.5 MPa. The average value of permeability showed 8.0E-02 cm/sec.