Fine Aggregate Research Articles

Evaluating the impact of waste marble on the compressive strength of traditional concrete using machine learning

Waste marble, an industrial byproduct generated from marble cutting and polishing processes, can be effectively utilized as a partial replacement in concrete mixtures. Incorporating waste marble in concrete not only addresses environmental concerns related to marble waste disposal but also contributes to the sustainability of construction materials. Using machine learning (ML) to predict the impact of waste marble on the compressive strength of traditional concrete offers several advantages over repeated laboratory experiments. ML offers a powerful alternative to costly and time-consuming laboratory experiments, enabling faster and more sustainable exploration of the potential of waste marble in improving concrete’s compressive strength. This research has focused on evaluating the impact of waste marble on the compressive strength of traditional concrete using machine learning (ML). Advanced ML techniques such as the Group Methods Data Handling Neural Network (GMDH-NN), Support Vector Regression (SVR), K-Nearest Neighbors (kNN) and Adaptive Boosting (AdaBoost) have been applied in this research work. The GMDH-NN model was created using GMDH Shell 3.0 software, while AdaBoost, SVR and kNN models were created using “Orange Data Mining” software version 3.36. Error indices such as the sum of squared error (SSE), mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), and Error (%), and performance metrics such as Accuracy % and the R2 between predicted and calculated compressive strength parameters were used to evaluate the overall behavior of the models. Finally, the Hoffman sensitivity analysis procedure was applied to determine the individual relative impact of the input variables on the output. At the end of the processes, a total of 1135 waste marble concrete entries were collected containing constituents such as the cement density (C), waste marble (WM), fine aggregate (FAg), coarse aggregate (CAg), water (W), superplasticizer (PL) and curing age (Age) used as input variables of the waste marble concrete model. The records were divided into training set (900 records = 80%) and validation set (235 records = 20%) following standard partitioning pattern reported in the literature. The kNN and AdaBoost, with SSE of 1408.5 MPa2 and 1397 MPa2 respectively and a tie Accuracy of 95.5% and R2 of 0.985 showed the best models suggesting excellent model performance while GMDH-NN showed the worst. Conversely, RF balances accuracy and model complexity, making it a practical alternative to kNN and AdaBoost. And lastly, Age, Coarse Aggregates, Water, and Plasticizer play the most significant roles in determining the compressive strength, while Cement, Waste Marble, and Fine Aggregates have comparatively smaller impacts. However, considering the standard proportion required for waste marble powder to replace cement, it showed a remarkable influence on the behavior of the concrete thus a recommended potential for its used as replacement for cement.

Compressive Strength Behavior of Recycled Concrete with Fine Aggregate Replacement Using Rubber Crumb

The use of recycled materials in concrete has drawn considerable attention in recent years as it means to enhance sustainability, strength, minimize landfill waste, cut carbon emissions and diminish the environmental influence of construction methods. This study focuses on investigating the compressive strength behaviour and sustainability analysis of rubberized concrete incorporating recycled aggregates. In this study, compressive strength tests have been conducted following standardized procedures to assess the load bearing capacity of rubberized concrete at different curing periods. The results will provide valuable information for engineers, researchers, and policymakers engaged in the development and utilization of sustainable construction practices. Recycle aggregates size ranging from 4.75 mm to 25 mm collected from crushing pile head from various construction site are utilized in this experimental research and also rubber crumbs are used as a partial substitute of fine aggregate at percentages of 6%,12%,18% and 25%, while maintaining a constant ratio of cement to water 0.45. The study was conducted at three different curing days of 7 days, 14 days and 28 days. From the test result, it has been noticed that conventional concrete has achieved the most effective result compared to the other percentages of mixtures of rubber crumb. Additionally, the compressive strength has been gradually decreased up to 56.82% in tandem with the increasing percentage of rubber crumb replacement in the specimens.

Predicting the Compressive Strength of Concrete Containing Recycled Fine Aggregate Using Early Age Test

Abstract The present research aims to make an attempt to predict the compressive strength for 28 and 56 days of concrete containing recycled fine aggregate by taking advantage of the compressive strength for early ages for the same mixture. Four groups of concrete mixtures were prepared, the variable in the groups is the compressive strength (25, 30, 35, and 40MPa), and for each strength, the natural fine aggregate was replaced with four different percentages of recycled fine aggregate (RFA) (0, 10, 20, and 30%) as volume ratios. After standard curing (water immersion) of the concrete samples, they were tested to obtain the compressive strength at different ages (3, 7, 28, 56 days), and based on experimental results, mathematical models were made through which the compressive strength for 28 and 56 days can be predicted based on the results of the compressive strength for 3 and 7 days. According to the proposed mathematical models, early age tests may be utilized to predict the compressive strength of concrete at 28 and 56 days, where the values of the determination coefficient for 28 and 56 days of compressive strength based on (3 and 7) days compressive strength were (84.8%), (86%), (79.2%). and (79.2%), respectively.

Diffusion and Consolidation of Slag-Based Geopolymer for Concrete Pavement Rehabilitation

Homogenized micro-crack crushing is an optimal rehabilitation technology for concrete pavement; however, when there are weak road base issues, some measures need to be taken to treat the diseases. Grouting is a common technique for addressing weak road base issues. This study developed a new visual indoor grouting test system to analyze the diffusion and consolidation of slag-based geopolymer slurry. The reactants of the geopolymer and the consolidation state of the slurry and aggregate were observed. Moreover, the reinforcement effect of the slurry on a weak road base was studied through the on-site grouting and excavation of the test pit. The results show that, during indoor grouting tests, as the size of the aggregate decreases, the slurry diffusion depth gradually decreases: only 9.5–4.75 mm aggregate formed a complete cylindrical specimen. In the tests of unformed cylindrical specimens, the 9.5–4.75 mm aggregate will develop 20–50 mm splitting surfaces, while the 4.75–2.36 mm aggregate will develop slurry bulbs and veins of different sizes, but the development is not obvious in the 2.36–1.18 mm aggregate. Fine aggregate grouting will exhibit the pressure filtration effect—especially for the 2.36–1.18 mm aggregate, the pressure filtration effect is the most obvious. An SEM microstructural analysis demonstrated that the geopolymer with a water–slag ratio of 0.4 has a faster hydration and dissolution, which results in a decrease in the density of local reactants. However, the polymerization of geopolymers is more complete. The pores of the coarse aggregate are larger and the slurry filling is denser, while the pores of the fine aggregate are smaller and the consolidation is loose locally. The consolidation of aggregates has cracks at local locations, but the width of the cracks is relatively small. On-site grouting applications revealed that the geopolymer slurry filled the bottom voids of pavement slabs and deep gaps in the road base layers, and the average deflection of the driveway decreased from 104.8 (0.001 mm) to 48 (0.001 mm) after grouting. Weak road base conditions were successfully treated, leading to a significant improvement in bearing capacity.

Utilization of Coal Bottom Ash as a Natural Sand Replacement in Mortar Containing Fly Ash

The substantial generation of waste ashes from coal thermal power plants (CTP), particularly fly ash (FA) and bottom ash (BA), poses significant environmental challenges; meanwhile, the exhaustion of natural river sand for the construction industry is more serious. The study aims to explore the use of BA as a sand replacement and FA as a partial cement substitute in mortar production, focusing on sustainability. In this research, FA and cement served as binder materials, with FA comprising 15% of the total binder mass. BA was incorporated as a fine aggregate, replacing sand at varying levels of 0%, 25%, 50%, 75%, and 100% by weight. The study assessed the effects of BA substitution on the mortar's compressive strength (CS), ultrasonic pulse velocity (UPV), water absorption (WA), thermal conductivity (TC), and resistance to sulfate attack. Additionally, scanning electron microscopy (SEM) was utilized to analyze the mortar's microstructure. Results indicate that substituting sand with BA negatively impacted all tested properties. As BA content increased, CS, UPV, and TC of mortar samples decreased, while WA and sulfate expansion increased markedly. At 56 days, the mortar samples exhibited CS values ranging from 20.6 to 57.0 MPa, UPV values from 3395 to 4203 m/s, WA values from 5.58% to 18.70%, and TC values from 0.89 to 1.73 W/m·K. Furthermore, the control mortar demonstrated a length change of 0.0218% due to sulfate attack, whereas the length changes for specimens with 25%, 50%, 75%, and 100% BA replacement were approximately 68.8%, 96.3%, 155.0%, and 162.4% higher, respectively.

Mechanical properties of self compacting concrete reinforced with hybrid fibers and industrial wastes under elevated heat treatment

Machine learning prediction of the mechanical properties of self-compacting concrete (SCC) reinforced with hybrid fibers, incorporating industrial wastes like fly ash and blast furnace slag, and cured under elevated heat provides a reliable and efficient alternative to traditional laboratory experiments. In this work, extensive literature review leading to the collection, sorting and curation of a global database representative of the mechanical properties of self-compacting concrete reinforced with hybrid fiber mixed with industrial wastes for sustainable construction was conducted. The collected database constituted traditional concrete components and admixtures such as Cement (C), Fly ash (FA), Slag (BFS), Fine Aggregate (FAg), Coarse Aggregate (CAg), Water (W), Superplasticizer (PL), Fiber (Fi), and Temperature (Temp.) studied under the mechanical properties such as the Compressive Strength (Fc), Tensile Strength (Fsp), and Flexural Strength (Ff). The collected 114 records were divided into training set (90 records = 80%) and validation set (24 records = 20%) following the guidelines for data partitioning for optimal performance in machine learning predictions. Different advanced machine learning methods created using “Weka Data Mining” software version 3.8.6 were applied such as “Semi-supervised classifier (Kstar)”, “M5 classifier (M5Rules), “Elastic net classifier (ElasticNet), “Correlated Nystrom Views (XNV)”, and “Decision Table (DT)” to predict the output. The Hoffman/Gardener and SHAP techniques are used to estimate the sensitivity of the input parameter on the output. Finally, various performance metrics are used to evaluate the reliability of the models. The results show that the machine learning models show varying degrees of predictive accuracy, with the Kstar and XNV models consistently outperforming others across all mechanical properties. However, Kstar with accuracies of 96.5%, 96.0%, and 97.0% for Fc, Fsp, and Ff predictions, respectively proposed the most decisive model. Also, the Hoffman and Gardener method highlights the role of the binders, chemical additives, and curing, whereas SHAP attributes greater importance to aggregates and binder interactions.

Drying shrinkage of ultra-high-performance concrete incorporating fine porous aggregate

The autogenous shrinkage of ultra-high-performance concrete (UHPC) can be mitigated using internal curing agents. However, owing to the low water/cement ratio typically used in UHPC, long-term drying shrinkage is significantly less pronounced than early-age autogenous shrinkage and has therefore received limited research attention. The impact of an internal curing agent (pre-wetted fine porous aggregate (FPA)) on the long-term drying shrinkage of UHPC was investigated in this work. The research provides new insights into the effects of FPA on rheological properties, multi-scale pore structures and hydration products. The results showed that, over 500 days, drying shrinkage accounted for 37–66% of the total shrinkage in UHPC with pre-wetted FPA. The FPA reduced non-connected pores but increased the volume and size of connected pores, with early drying shrinkage at 14 days strongly associated with coarser pore structures. Additionally, the water released from the FPA promoted the formation of C-S-H (II) gels with higher interlayer water content. This water was gradually released during extended curing, up to 500 days, and this contributed partially to the increased drying shrinkage observed at later stages. These findings emphasise that the incorporation of FPA contributes to higher drying shrinkage, underscoring the importance of considering this factor in the design of low-shrinkage UHPC.

Performance Evaluation of Shotcrete Mortar with Silicon Manganese Slag as Substitute for Fine Aggregate

Shotcrete is a versatile construction material, yet its performance limitations, such as high rebound rates and poor adhesion, demand technological improvements to ensure structural reliability. Silicon manganese (SiMn) slag, a by-product of SiMn alloy production, has gained attention as a potential sustainable alternative to natural aggregates in construction materials, addressing both resource depletion and carbon reduction challenges in the industry. This study is conducted to develop and evaluate a new mix design of mortar incorporating SiMn slag as fine aggregate, focusing on enhancing performance. Mixtures with varying percentages (0%, 30%, 50%, 70%, and 100%) of SiMn slag as a fine aggregate replacement were evaluated for fresh properties (air content, slump), mechanical performance (compressive strength, flexural strength, splitting tensile strength), durability (chloride ion penetration resistance, freeze–thaw resistance, carbonation resistance), and constructability (rebound rate, free shrinkage) to assess suitability as mortar for shotcrete. The experimental results demonstrated that the mixture with 50% SiMn slag replacement demonstrated the most balanced performance, showing an increase of 12.33% in compressive strength, 8.97% in splitting tensile strength, and 18.4% in flexural strength compared to the control. Durability properties also improved by an average of 11.93%, while rebound rate and shrinkage were significantly reduced. The findings confirm that SiMn slag is a technically viable and advantageous substitute for fine aggregates in shotcrete. Further research is needed to refine its economic feasibility and broaden its implementation in sustainable construction.

Incorporating recycled plastic aggregates with coarse and fine aggregates for enhancing the properties of concrete

Incorporating recycled plastic aggregates with coarse and fine aggregates for enhancing the properties of concrete

Member Size Effect in Seebeck Coefficient of Cement Composites Incorporating Silicon Carbide

This study investigates the size effect on the Seebeck coefficient (SC) in cement composites incorporating silicon carbide (SiC). Two specimen shapes, cubic (50 × 50 × 50 mm3) and beam (40 × 40 × 160 mm3), were analyzed with varying SiC substitution ratios (0%, 50%, and 100%) for fine aggregates. Thermal and electrical conductivities were measured to assess their influence on the SC. The results showed that a higher SiC content increased porosity, which reduced mechanical strength but significantly improved thermal and electrical conductivities. Thermal conductivity increased from 1.88 W/mK (0% substitution) to 11.89 W/mK (100% substitution), while electrical conductivity showed an improvement from 0.0056 S/m to 0.065 S/m. Cubic specimens exhibited higher SC values compared to beam specimens, with a maximum SC of 1374 μV/K at 100% SiC substitution, attributed to shorter thermal diffusion distances. The findings suggest that optimizing member size and SiC content can significantly improve the thermoelectric performance of cement composites, potentially enhancing energy efficiency in construction applications.

Hysteresis performance and design optimization of rubber concrete anti‐collision layer of concrete bridge piers

AbstractRubber concrete, with characteristics of light weight, remarkable toughness, impact resistance, and durability, has been gaining increasing application in engineering. This study explored the mechanical properties of rubber concrete, analyzed its performance as anti‐collision layers, and optimized the layers’ thickness. First of all, static and hysteresis experiments were implemented to obtain the compressive strength, elastic modulus, and energy dissipation factor of rubber concrete. Rubber concrete specimens were made by replacing the fine aggregate of C30 concrete with rubber particles of equivalent volume. The rubber particles were categorized into two size groups: 1.5–3.0 mm and 3.0–5.0 mm. Within each size category, the rubber particles were incorporated into the concrete fine aggregates at replacement volumes of 5%, 10%, and 20%. Then truck‐bridge collision models with different thicknesses of anti‐collision layers were conducted to assess the metric variations in anti‐collision performance, including impact force, top displacement of the bridge abutment, Von Mises stress, and damping dissipation energy. Finally, a recommendation on cost‐effective thickness for the anti‐collision layer was given by the indicator weights generated from the triangular fuzzy analytic hierarchy process and the metric evaluation scores of anti‐collision performance. It is found that the compressive strength and elastic modulus of rubber concrete decrease with the increase of rubber particle size and rubber content. The loss factor increases with the increase of rubber content and the amplitude of the loading force. With the increase of rubber concrete anti‐collision layers from 0 to 250 mm, the peak impact force and peak Mises stress decrease, while the peak displacement at the top of the bridge abutment and peak damping dissipation energy decrease and then increase at the thickness of 250 mm. For the collision scenario in this study, the cost‐effective thickness of the rubber concrete layer is 200 mm.

Sustainable Paver Block Development Using Silica Fume and Granite Waste

The rapid urbanization and increasing construction activities have led to a high demand for paver blocks, raising concerns about the depletion of natural resources and environmental sustainability. This study explores the development of sustainable paver blocks by incorporating silica fume and granite waste as partial replacements for cement and fine aggregates, respectively. Silica fume, a byproduct of the silicon and ferrosilicon industry, enhances the mechanical properties and durability of concrete, while granite waste, a byproduct of stone processing industries, serves as an eco-friendly alternative to sand. The research investigates the physical and mechanical properties of the developed paver blocks, including compressive strength, water absorption, and durability. Experimental results indicate that the optimized mix design with silica fume and granite waste not only improves strength and performance but also reduces the carbon footprint associated with conventional paver block production. The study concludes that utilizing industrial waste materials in paver block manufacturing presents a viable and sustainable solution for eco-friendly construction practices. Key words: Granite wastes, Silica Fume, Partial replacement, Eco-friendly, Behavioral study.

Monotonic Response of Beams Castedwith Different Types of Concrete

Structural elements. This means the structural behavior can be quantified by considering the behavior of each structural element in each load path. Concrete is a material known for its great strength. Regardless, there are a few weaknesses, which must be taken in consideration in the design of concrete structural elements. Basically, concrete is made of three main ingredients: Portland cement, water, and aggregates (sand and stone).In order to improve tensile strength and ductility (capacity to stretch and deform prior to failure) in concrete, so this paper discus some types of concrete and record the effect on beams. Reactive powder concrete (RPC) is an actual concrete mixture, it is a special type of concrete because mix concrete (coarse and fine aggregate ) replaced by fine sand size (150-400)µm. In the experimental comparison the mechanical properties( compressive , splitting tensile and flexural )strength of plain RPC and high and normal strength concrete. Each set consisted of (4) cubes of (100×100×100_mm, (8) cylinder of (150×300mm) and (4) prism of (100x100x500) mm and consisted of (4) beam of (1000×100×400)mm. The results shown that the maximum compressive strength is 107 MPa and the maximum splitting tensile 9 MPa of RPC comparison high and normal strength concrete. The result of the second part shown increased RPC reinforced concrete the firstcrack288 MPa and ultimate crack 380MPa comparison high and normal strength concrete and the mode of failure of RPC (flexural-shear).

A Comparative Assessment of Chemical Properties, Toxicity and Mechanical Performance of Industrial Waste Materials as Fine Aggregate for Eco-friendly Paving Application

Abstract The rapid growth of industrial processes has led to a significant increase in the generation of various types of solid waste. This has created an opportunity to explore the potential utilization of such waste materials in pavement applications, addressing environmental concerns and offering potential cost savings in construction. This study explores the feasibility of using industrial waste materials: bottom ash from power plants and waste garnet from abrasive blasting as fine aggregates in asphalt mixtures under aging conditions. Two asphalt mixtures incorporating these waste materials were designed and evaluated against a conventional control mixture. The research analyzed mechanical, chemical, and leaching properties. Findings indicate that asphalt mixtures with waste garnet generally outperformed those with bottom ash in terms of bitumen content, stability, chemical properties, toxicity, rutting resistance, and indirect tensile strength. However, bottom ash mixtures showed better performance in cantabro loss, resilient modulus, and moisture sensitivity. Both waste materials met performance requirements, with waste garnet proving particularly promising as an eco-friendly paving material.

Exploring the impact of pretreatment and particle size variation on properties of rubberized concrete

This study comprises the influence of particle sizes of discarded tire rubber with and without pre-treatment to check the hardened properties of rubberized concrete (RC) in analogy to control concrete. Fine aggregates from concrete are volumetrically substituted using untreated and pre-treated rubber particles of three different sizes up to 20% in part, with an increment of 5%. Pre-treatment using two different pre-treatment methods i.e., sodium hydroxide (NaOH) and silica fume and NaOH was adopted. Properties of fresh concrete-i.e., density, workability, and toughened concrete strengths as compressive, flexural, and indirect tensile strengths were assessed with the control concrete. Along with these, unconventional properties like cylindrical compressive strength and abrasion, resistance to impact, and water absorption are compared. The mechanical properties of RC were found to be similar to conventional concrete, as the compressive strength for RC with pretreated rubber fibers up to 10% obtained was 61.5 MPa while flexural and split tensile strength was above 5.6 MPa. The abrasion resistance was obtained for RC with rubber fibers from 0.98 to 1.46 mm up to 20% substitution against 1.34 mm of control concrete. Modified concrete with pre-treated rubber particles showed better performance than concrete with untreated rubber particles with coarser sizes.

Exploring the Eco-Friendly Potential of Local Aggregates: A Study on the Use of Senoni Stone and Mahakam Sand in Asphalt Concrete Mixes

This study investigates the potential environmental benefits of employing locally produced materials, such as Senoni Stone (SS) and Mahakam Sand (MS), in asphalt concrete mixtures, aiming to achieve a balance between environmental sustainability and performance requirements. Since aggregateσ constitute 75%-85% of the total weight of asphalt mixtures, it serves as a primary component. The aggregates used in the specific mixtures are required to meet the Indonesian National Standard (SNI) specifications. In the current work, the Asphalt Concrete Wearing Course (AC-WC) combination was examined using SS as the coarse aggregate and MS as the fine aggregate, both of which originate from East Kalimantan. The volumetric metrics analyzed include Void in Mix (VIM), Void Mineral Aggregate (VMA), and Void Filled Bitumen (VFB). Asphalt concentration varied, with values of 4.5%, 5%, 5.5%, 6%, and 6.5% with increments of 0.5%. VIM values decreased as the asphalt quantity increased, with the corresponding VIM values being 9.26%, 4.51%, 4.33%, 4.17%, and 3.25%. The VMA values recorded for each asphalt content were 19.18%, 16.05%, 16.97%, 17.92%, and 18.56%, respectively, while the VFB values for the same contents were 51.7%, 71.87%, 74.49%, 76.68%, and 77.86%. It is therefore recommended that locally sourced materials, such as SS and MS, be prioritized in asphalt concrete mixtures to support sustainable construction practices. This approach not only reduces environmental impact, but also enhances resource efficiency and strengthens local economies.

Experimental Study of the Effect of Wire Fiber Addition on the Mechanical Strength of Preplaced Aggregate Concrete

Preplaced Aggregate Concrete (PAC) is a specialized type of concrete, with low tensile strength, making it prone to brittle failure, used in the construction industry. One effective way to enhance durability and minimize cracking is by incorporating fibers into the mix. This study explores the use of wire fibers, produced by cutting wire ropes into pieces approximately 1 mm in diameter and 60 mm in length. Five different concrete mixtures were tested to evaluate the mechanical strength of PAC and Preplaced Aggregate Wire Fiber Concrete (PAWFC). The wire fiber content varied at 0%, 0.25%, 0.5%, 0.75%, and 1% of the total concrete volume, while the proportions of cement, fine and coarse aggregates, water, and Super Plasticizer (SP) remained constant. A mortar mix with a cement-to-sand ratio of 1 and a water-to-cement ratio of 0.45 was used. The mechanical properties, including compressive strength, tensile strength, and modulus of rupture were assessed following the ASTM standards. The results showed that adding wire fiber significantly improved the mechanical strength of PAWFC. Specifically, the optimum 1% wire fiber addition increased compressive strength by 11.23%, tensile strength by 36.85%, and modulus of rupture by 17.23%.

Utilization of drinking water treatment sludge as a fine aggregate substitute in ceramic waste-based geopolymer composite mortar

Utilization of drinking water treatment sludge as a fine aggregate substitute in ceramic waste-based geopolymer composite mortar

Innovative Approach to Foam Concrete Production by Utilizing Recycled Foam Concrete as a Sustainable Alternative

Foam concrete, distinguished by its lightweight properties and versatility in construction, is a porous material produced from cement, water, fine aggregate, and foam. It contains numerous voids and lacks coarse aggregate, which accounts for its lightweight and low density. It has been widely used in roofing, partition walls, and insulation applications. This study explores an innovative approach to foam concrete production by investigating the effect of using recycled foam concrete waste, processed into various sizes of lightweight aggregate. The water-to-cement and cement-to-aggregate ratios were maintained at 0.45 and 1:1.3, respectively. The research involved replacing 50% of the aggregate volume with recycled waste from foam concrete, using specified aggregate sizes of Gradation levels of four aggregate sizes (12.5-9.50) mm, (9.50-4.75) mm (4.75-2.36) mm, and (2.36-1.18) mm. Results showed that the optimal size for use was 9.50-4.75 mm, which enhanced compressive strength, and tensile strength while increasing water absorption at 28 days by percentages compared to traditional FC mix. The study aims to minimize the use of natural aggregate resources and reduce construction waste. Through a comprehensive experimental program including material characterization, and mechanical performance testing, the findings are expected to provide valuable contributions to sustainable construction practices.

Assessing the effect of particle characteristics on the rheological properties of mortar with recycled fine aggregate

Assessing the effect of particle characteristics on the rheological properties of mortar with recycled fine aggregate