Search Results (12)

The combined effects of global warming and urbanisation have intensified the urban heat island (UHI) phenomenon and thermal stress, especially in the summer season. This study develops an integrated multi-scale framework to quantify the sustainability in terms of the thermal performance of high albedo interlocking concrete block pavement (ICBP) in the city of Turin, Italy. The framework combines: (1) experimental campaigns to establish baseline albedo values, using an albedometer (in accordance with the standard ASTM E1918-21 and E1980-24); (2) in situ measurements to assess the performance of ICBP in three parking areas; (3) satellite analysis using Landsat 8-9 and Sentinel-2 images to derive the land surface temperature (LST) and quantify changes in the surface urban heat island intensity (SUHII). In situ measurements showed an average albedo of 0.20 for ICBP, lower values for aged surfaces and about 0.08 for asphalt. Satellite analysis confirmed the effectiveness of the substitution of asphalt surface pavements with ICBP, revealing an increase of over 30% in both the average albedo and the solar reflectance index (SRI). These results are also combined with the 15% decrease in SUHII. Combining on-site measurements and satellite analysis provides a comprehensive framework for quantifying surface urban heat island effects and thermal performances of more sustainable road pavements. These findings support high albedo ICBP as an effective strategy for UHI mitigation. Full article

The rapid expansion of urban areas has increased the prevalence of impermeable surfaces, intensifying flooding risks by disrupting natural water infiltration. Permeable pavements have emerged as a sustainable alternative, capable of reducing stormwater runoff, improving surface friction, and mitigating urban heat island effects. Nevertheless, their broader implementation is often hindered by issues such as clogging and limited mechanical strength resulting from high porosity. This study examines the design of interlocking permeable blocks utilizing ultra-high-performance concrete (UHPC) to strike a balance between enhanced drainage capacity and high structural performance. A topology optimization (TO) strategy was applied to numerically model the ideal block geometry, incorporating 105 drainage channels with a diameter of 6 mm—chosen to ensure manufacturability and structural integrity. The UHPC formulation was developed using particle packing optimization with ordinary Portland cement (OPC), silica fume, and limestone filler to reduce binder content while achieving superior strength and workability, guided by rheological assessments. Experimental tests revealed that the perforated UHPC blocks reached compressive strengths of 87.8 MPa at 7 days and 101.0 MPa at 28 days, whereas the solid UHPC blocks achieved compressive strengths of 125.8 MPa and 146.2 MPa, respectively. In contrast, commercial permeable concrete blocks reached only 28.9 MPa at 28 days. Despite a reduction of approximately 30.9% in strength due to perforations, the UHPC-105holes blocks still far exceed the 41 MPa threshold required for certain structural applications. These results highlight the mechanical superiority of the UHPC blocks and confirm their viability for structural use even with enhanced permeability features. The present research emphasizes mechanical and structural performance, while future work will address hydraulic conductivity and anticlogging behavior. Overall, the findings support the use of topology-optimized UHPC permeable blocks as a resilient solution for sustainable urban drainage systems, combining durability, strength, and environmental performance. Full article

This paper aims to review the performance analysis of interlocking concrete block pavement with by-products such as coconut fibers, and construction and demolition recycled materials, and to compare their skills with asphalt pavement, especially for light-traffic urban road applications. The focus is on mechanical behavior (mix parameters and the influence of by-products), pavement design, sustainability (the heat island effect), the management of contaminant concentrations within infiltration related to permeability, and Life Cycle Assessment. Considering the overall performance analysis, interlocking concrete block pavement was the most attractive alternative because it was approximately 33–44% cheaper in the maintenance process, cooler over a range of 2.2–15 °C, and more permeable by 0.4 cm/s to 0.6 cm/s than asphalt pavement, saving costs and improving drainage and human thermal comfort. However, asphalt pavement was around 35% cheaper during the construction phase (mainly due to energy consumption), and it presented a 32% lower nitrogen oxide concentration. This paper showed the advantages and disadvantages of both types of pavements. A further breakdown should be developed and integrated into the decision-making process about choosing between solutions. Full article

This paper examines the compressive, flexural and tensile strength, ultrasonic pulse velocity, unit weight, water absorption, freeze-thawing, thermal and abrasion resistance, and microstructural properties of Interlocking Concrete Block Paving (ICBP) containing major industrial and agricultural wastes along with an assessment of their environmental effects, with a specific focus on recent work. The color, shape, and patterns of the blocks, their advantages, and their relationship with sustainability are discussed in this study. In addition, a limited number of studies that investigated the use of other byproducts are presented. Based on a review of the existing studies in the literature, recommendations are made for future studies. It has been determined that up to 30% inclusion of waste evaluated in ICBP provides optimal performance in terms of the evaluated properties. Moreover, as ICBP provides opportunities for low-energy concrete block production, the environmental burden and total cost of concrete and concrete block pavements can be reduced. Considering these benefits, studies performed on this subject seem promising. However, one of the missing points in ICBP is that the surface layer is not homogeneous due to the presence of various material types due to the coating design and analysis method. Therefore, modified slab analysis, layered elastic analysis, and finite element analysis can be used to analyze ICBP in detail. Full article

Concrete block pavement is used as a modern pavement type owing to its economic benefits. The physical properties, mechanical properties, and functional characteristics of bedding sand and joint sand, the main components of concrete block pavements, should be accurately understood. Owing to the discontinuous structure of these pavements, load transfer efficiency (LTE) is the most important index from the perspective of performance. The factors that affect LTE are bedding sand (type, grading, and thickness), joint sand (type and grading), and concrete block (shape and pattern). Therefore, the optimal design for concrete block pavements can be achieved by analyzing each factor. In this study, three types of sand (river, quartz, and manufactured) were selected to examine the mechanical properties via direct transfer experiments. It was observed that the shear strength of river sand was the highest. It was also found that the difference between the shear strength and the internal friction angle (according to the content of 0.6 mm in the grading of bedding sand) was not large, and the shear strength and the friction angle increased as the content increased to 0.075 mm. In addition, the load transfer characteristics of the joint and rotational interlocking of the block were evaluated through a non-destructive test using the degree of joint filling, block shape, and construction pattern as variables. As a result, the degree of joint filling had the greatest effect on the load transfer characteristics of the joint and rotational interlocking of the block. The effect of the block shape was larger than that of the construction pattern. When a heavy load is applied, the LTE between blocks must be maintained at 50% or more, and the rotation of blocks at 0.6° or less, if 75% or more of the joint must be filled for preventing excessive vertical deformation. Full article

A reduction in potable water demand in buildings could be made by using non-potable water for certain uses, such as flushing toilets. This represents a sustainable strategy that results in potable water savings while also using an underutilised resource. This work assesses the use of permeable interlocking concrete pavement to filter stormwater that could be used for non-potable purposes in buildings. Two pavement model systems were tested. One of the model systems presents a filter course layer with coarse sand and the other model system has no filter course layer. In order to evaluate the filtering capacity, the model systems were exposed to rain events. The amount of water infiltrated through the layers was measured to represent the potential quantity available for use. Stormwater runoff samples were collected from a parking lot paved with impermeable interlocked blocks and then, these were tested in both model systems. Water samples were subjected to quality tests according to the parameters recommended by the Brazilian National Water Agency. The model system with no filter course showed filtering capacity higher (88.1%) than the one with a filter course layer (78.8%). The model system with a filter course layer was able to reduce fecal coliforms (54.7%), total suspended solids (62.5%), biochemical oxygen demand (78.8%), and total phosphorus concentrations (55.6%). Biochemical oxygen demand (42.4%) and total phosphorus concentrations (44.4%) increased in the model system with no filter course layer. In conclusion, one can state that the filter course layer used in permeable interlocking concrete pavement can contribute to decreasing pollutants and can improve stormwater quality. The use of permeable interlocking concrete pavement showed to be a potential alternative for filtering stormwater prior to subsequent treatment for non-potable uses in buildings. Full article

The mechanistic design of a concrete block pavement (CBP) can be very complicated and often requires the use of computer programs. This paper presents a new mechanistic-empirical method, which is implemented in a computer program (DesignPave) that calculates base course/sub-base thicknesses for a range of design inputs such as traffic load, interlocking properties, and material stiffness. A range of virgin and recycled unbound granular materials were also experimentally tested to characterize them for possible use as base course or sub-base materials. Combining the new mechanistic-empirical method and the range of base course/sub-base course materials (virgin and recycled aggregates), it was found that while a CBP containing recycled aggregates did not offer a significant direct financial benefit based on the characteristics or material costs, the associated environmental benefits were very high. Full article

Paving blocks are today a popular paving solution for urban surfaces. Considering the wide variety of products currently on the market, it is possible to build pavements that differ in terms of functionality, bearing capacity, skid resistance, visual impact, and aesthetic integration with the surrounding landscape. Interlocking concrete paving block is the most common construction technology considering its low cost and its easy installation. Different wastes and second-hand materials have recently been tested in order to completely or partially replace the raw materials used for the production of paving blocks. In this paper, a waste basalt powder is used for the production of alternative paving blocks through the alkali-activation process. Two different synthetic blocks were produced, with and without aggregates. Taking into account the EN 1338 standard for concrete paving blocks, a complete laboratory characterization is proposed for the two experimental blocks. Tests highlighted positive results and downsides that need to be optimized in order to convert the laboratory production to an industrial scale. Full article

This study examines the hydrologic and environmental performance of three types of permeable pavement designs: Porous Concrete Pavement (PCP), Permeable Interlocking Concrete (PICP), and Interlocking Block Pavement with Gravel (IBPG) in the semi-arid South Texas. Outflow rate, storage, Normalized Volume Reduction (NVR), Normalized Load Reductions (NLR) of Total Suspended Solids (TSS), and Biochemical Oxygen Demand (BOD₅) were compared to results obtained from adjacent traditional pavements at different regional parking lots. A notable percentage of peak flow attenuation of approximately 31–100% was observed when permeable pavements were constructed and implemented. IBPG was capable to hold runoff from rainfall depths up to 136 mm prior to flooding. PCP was the most satisfactory in reducing surface runoff (NVR: 2.81 × 10⁻³ ± 0.67 × 10⁻³ m³/m²/mm), which was significantly (p < 0.05) higher (98%) than the traditional pavement. PCP was also very effective in TSS removal (NLR: 244 × 10⁻⁵ ± 143 × 10⁻⁵ kg/m²/mm), which was an increase of over 80% removal than traditional pavement. IBPG (NLR: 7.14 × 10⁻⁵ ± 7.19 × 10⁻⁵ kg/m²/mm) showed a significantly (p < 0.05) higher (46%) BOD₅ removal over traditional pavement. These results demonstrate that the type of permeable pavement and the underlying media can significantly influence the runoff reduction and infiltration in this climatic region. Full article

This study used the Source Loading and Management Model for Windows (WinSLAMM) to develop a set of calibrated hydrologic models for three types of regional permeable pavements—porous concrete pavement (PCP), permeable interlocking concrete pavement (PICP), and interlocking block pavement with gravel (IBPG). The objective was to assess the hydrologic performance of permeable pavements, including the runoff depth, peak discharge, percentage increment in runoff reduction of pavements as a function of rainfall depth, development area, and base aggregate porosity, respectively. The permeable pavements were monitored over a wide range of rainfall events in the semi-arid Lower Rio Grande Valley of South Texas. Data regarding rainfall intensities, source characterizations, runoff coefficients, and pavement design were initialized as WinSLAMM input. Validation results showed that the calibrated models could over or under-predict runoff reduction within a 30% error range. PCP and IBPG were very effective and could be capable of handling storms as large as 50-year frequency over a 24-h time period. The modeling results showed that PCP might require a 50–60% lesser footprint area as compared to PICP and IBPG, respectively. Additionally, PCP might be able to store 30% additional runoff if the porosity of base aggregates was increased by 40%. Full article

Porous mixtures and Interlocking Concrete Block Pavements (ICBP) are the most widely used surfaces in Permeable Pavement Systems (PPS). Despite the fact that there are many studies based on the hydrological performance of PPS, there are few long-term studies that identify the end of life of PPS regarding their hydrological performance. A field study has been developed over 10 years in the experimental car park “Las Llamas” in the city of Santander, Northern Spain. Permeability was measured in 37 car park bays (nine Polymer-Modified Porous Concrete, nine Porous Asphalt, and 17 ICBP of two different designs). Tests were conducted under the Spanish Standard NLT-327/00 for the porous-mixture surfaces and the ASTM methods C1701/C1701M-17a and C1781/C1781M-15 for porous mixtures and ICBP, respectively. No maintenance was carried out in this car park since it was opened to traffic in 2008, allowing for the assessment and identification of the hydrological failure of each surface. The research showed that after 10 years of operation without maintenance, the bays constructed using porous mixtures were completely clogged, reaching the end of their operational life after nine years. However, ICBP maintained high infiltration rates, showing better resilience to sediment clogging. Further research is needed to confirm the evolution of ICBP surfaces. Full article

Permeable interlocking concrete pavements (PICP) are specifically designed to remove sediment and other pollutants from stormwater runoff. Over time, this can lead to clogging of the PICP system. Previous research has shown that much of the clogging occurs on the bedding aggregate directly below the paving joints, while the remainder of the aggregate is unaffected. This paper describes a proof of concept study to delay the effects of clogging by making more efficient use of the bedding aggregate used in PICP systems. Lateral drainage slots were cut into the underside of PICP blocks to allow sediment-laden stormwater to access, and be filtered by, a greater surface area of bedding aggregate. Eight different slot designs were trialed in the study to determine which of the slot designs made the most efficient use of the bedding aggregate to filter the sediment from the stormwater. The study results demonstrated that the eight drainage slot designs deposited between 25% and 366% more sediment (by weight) beneath the pavers than the control pavement. The results of the study suggest that PICP systems with drainage slots cast into their bases would take much longer to clog than unmodified pavers, thereby proving the concept of this study. Full article