Porous Concrete Mixtures Research Articles

Investigating the Relationship between Porosity and Compressive Strength for Porous Concrete as a Sustainable Pavement

In this study, the relationship between porosity and compressive strength for porous concrete (PC) was investigated. The effect of mixture design parameters particularly, water-to-cement ratio (W/C) and size of aggregate on the porosity and compressive strength of PC was evaluated. To investigate the role of W/C and aggregate size on this testing procedure, the experiments were performed on specimens of two aggregates size and four range of W/C. The PC mixtures were made with W/C in the range of 0.28-0.34, 350kg/m3 cement content and 19.5mm and 9.5 maximum size of aggregate. PC mixes were made from each aggregate and were tested. The results showed that the W/C and aggregate size are key parameters which significantly affect the porosity of PC. Investigation of compressive strength and porosity for the various mix designs showed a clear dependence on these parameters. The measured values fall within the expected range obtained from a review of the literature. Compressive strength of coarse porous concrete (CPC) is smaller than compressive strength of fine porous concrete (FPC) and the porosity of CPC are bigger than porosity of FPC. In general, increased W/C yields a smaller porosity and higher compressive strength. This approach can reduce the number of trial batches needs for target performance of PC samples.

Eco-friendly porous concrete using bottom ash aggregate for marine ranch application.

This article presents the test results of an investigation carried out on the reuse of coal bottom ash aggregate as a substitute material for coarse aggregate in porous concrete production for marine ranch applications. The experimental parameters were the rate of bottom ash aggregate substitution (30%, 50% and 100%) and the target void ratio (15%, 20% and 25%). The cement-coated granular fertiliser was substituted into a bottom ash aggregate concrete mixture to improve marine ranch applications. The results of leaching tests revealed that the bottom ash aggregate has only a negligible amount of the ten deleterious substances specified in the Ministry of Environment - Enforcement Regulation of the Waste Management Act of Republic Korea. The large amount of bubbles/air gaps in the bottom ash aggregate increased the voids of the concrete mixtures in all target void ratios, and decreased the compressive strength of the porous concrete mixture; however, the mixture substituted with 30% and 10% of bottom ash aggregate and granular fertiliser, respectively, showed an equal strength to the control mixture. The sea water resistibility of the bottom ash aggregate substituted mixture was relatively equal to that of the control mixture, and also showed a great deal of improvement in the degree of marine organism adhesion compared with the control mixture. No fatality of fish was observed in the fish toxicity test, which suggested that bottom ash aggregate was a harmless material and that the combination of bottom ash aggregate and granular fertiliser with substitution rates of 30% and 10%, respectively, can be effectively used in porous concrete production for marine ranch application.

Drop Weight Impact Strength Measurement Method for Porous Concrete Using Laser Doppler Velocimetry

In this study, an experimental configuration that reveals the dynamic response of porous concretes in a drop weight impact test was introduced. Through the measurement of particle velocity at the interface, between the impactor and the concrete target, the dynamic response was obtained in an easily applicable way. Laser Doppler velocimetry (LDV) was used in monitoring the time history of the particle velocity at the interface, which was subsequently analyzed to determine the dynamic strengths of the concrete specimens tested. The velocity measurements were analyzed using a special reverberation application of the impedance mismatch method. The test results showed that the experimental configuration was sufficient to measure the dynamic strengths of porous concretes and a normal concrete with moderate strength. The method was validated by using impactors having different dynamic impedances in testing the same material and was also verified to be precise enough to distinguish between different types of porous concrete mixtures.

Porous concrete mixtures for pervious urban pavements

The present study aimed to analyze the hydraulic and mechanical behaviour of a series of roller-compacted, laboratory porous concrete mixtures. The mix design variables examined were the actual void ratio in the hardened concrete and the water/cement ratio. From these results the better dosages from the mechanical and hydraulical behaviour point of view were determined. One of the designs developed was found to exhibit excellent hydraulic capacity and 20% greater strength than the mixtures recommended in the literature. Moreover, concrete with an actual void ratio of only 14% was observed to meet permeability requirements. Maximum flexural strength of concretes with different w/c ratios was achieved with a cement paste content of 250 l/m3. Relationships were found between the void ratio and both 28-day concrete permeability and flexural strength. Finally, the doses exhibiting the best mechanical and hydraulic performance were identified.

친환경 도로포장용 투수콘크리트의 제조와 이를 이용한 도로포장시스템의 수질정화특성

Stormwater pollution is a major problem in urban areas. Pollutants like heavy metals and harmful chemicals in the runoff can endanger soil and ground water, when they are not sufficiently removed doting infiltration. Strength and infiltration capacity of porous concrete are the major problems that must be considered if permeable pavement system are demanded to be used in a drive way application. In this study, a series of compacted porous concrete mixtures and the system of pavement ate tested for the physical characteristics like compressive strength, flexural strength, unit weight, porosity, water permeability, and the purification capacity of contaminated water. The test results obtained indicate that the strength and infiltration capacity of porous concrete are strongly related to its matrix proportion and compaction energy and providing adequate filter layers underneath pavement surface course is one of the most important design considerations of permeable pavement system for pollution retention purpose.