Lightweight Expanded Clay Aggregate Research Articles

Durability Evaluation of GGBS-RHA-Based Geopolymer Concrete Along with Lightweight Expanded Clay Aggregate Using SEM Images and EDAX Analysis

The durability of geopolymer concrete containing Ground Granulated Blast Furnace Slag (GGBS) and Rice Husk Ash (RHA), along with Lightweight Expanded Clay Aggregate (LECA), was investigated. Six different LWGPC mixtures were made with NaOH molarities of 8, 10, and 12M. For each molarity, two combinations of source materials were selected: 100% GGBS (G) and 80% GGBS with 20% RHA (RG). In all the mixtures, coarse aggregate was substituted with 35% LECA. LWGPC mixtures were exposed to 3% HCl, 5% MgSO4, and 3.5% NaCl for studying the durability properties. The test results demonstrate that 100% GGBS with 12M NaOH (12G) outperformed all other mixtures. The residual compressive strength of 12G mix LWGPC specimens after six months of exposure was found to be 86.4% in an acid environment, 90.6% in a sulfate environment, and 91.4% in a salt environment. The elemental composition analyzed using EDAX reveals that silica, alumina, calcium, and sodium are the predominant elements that form a dense microstructure with N-A-S-H, C-A-S-H, and C-S-H. Further, the inner properties of the specimens exposed to chemicals were examined using MATLAB R2023b and ImageJ 1.54f based on SEM images. The SEM image showed that the porosity of LWGPC specimens ranged from 0.5194 to 0.6748 µm, signifying an enhanced durability performance. The experimental results and microstructural analysis show that the LWGPC incorporating RHA and GGBS with LECA offers a superior performance, making it a promising solution for sustainable and durable construction.

Modelling and optimisation of the structural performance of lightweight polypropylene fibre-reinforced LECA concrete

Lightweight fibre-reinforced concrete integrates the advantages of lightweight aggregates with the strength-enhancing properties of fibres, resulting in a lighter composite with enhanced impact and mechanical performance. However, achieving an optimal balance between structural weight, and performance remains a challenging endeavour. This study investigates the mechanical properties, impact energy absorptions, flexural toughness, and crack resistance of lightweight fibre-reinforced concrete with the coarse aggregate entirely replaced with lightweight expanded clay aggregate (LECA). Concrete mixes containing 0 %, 0.5 %, 0.75 %, and 1.0 % Polypropylene fibre (PPF) and 10 % micro-silica were experimentally investigated. Predictions for concrete mixes with up to 2 % PPF were made using regression models developed from experimental data. The experimental and predicted results were analysed using response surface methodology. The findings reveal significant enhancements of up to 300 % and 570 % in toughness indices I5 and I10 at 1 % PPF, coupled with a 55.4 % increase in residual strength. Furthermore, an optimised slab thickness of 47 mm containing 1.73 % PPF yielded optimal impact energy absorption of 680 J and 2384 J and crack resistance of 3823 MPa and 16279 MPa at service and ultimate loading, respectively. These metrics represent improvements of 4.8, 15.2, 37, and 56 times, respectively, compared to the control samples. These substantial advancements highlight the potential of lightweight fibre-reinforced LECA concrete in engineering applications where balancing impact energy absorption, crack resistance, and structural weight is crucial. This innovative approach promises a transformative impact on the construction industry, paving the way for more efficient and resilient infrastructure.

Unidirectional steel wire reinforced metal matrix syntactic foams

Abstract A double composite structure has been successfully produced using vacuum infiltration. In this structure, the matrix was unalloyed aluminium filled with Lightweight Expanded Clay Aggregate Particles to create metal matrix syntactic foam, and stainless steel wires were placed inside this matrix as unidirectional reinforcement. The wires created a shape-locking bond with the matrix owing to their wave-like form, which helped to prevent reinforcement pullout. Based on the acquired tensile data, the tensile strength of the specimens calculated with the theoretical maximum area of reinforcement wires is Rm, theoretical = 1063 ± 192 MPa, while the tensile strength of the individual wires is Rm, wires = 882 ± 2, which leads to the conclusion that the matrix distributed some of the stress.

Use of the organic fraction from recycled alkaline batteries in the manufacture of LECAs: Experimental and Environmental Assessment

The industrial alkaline battery recycling process produces an organic fraction (OF) consisting of waste paper, plastic and cardboard. Currently, this OF is used for energy recovery, given the absence of a successful alternative recycling approach, attributed to its contamination and limited economic value. This study explored the valorisation of the organic fraction derived from the recycling of alkaline batteries as a foaming agent in the production of lightweight expanded clay aggregates (LECAs). The OF, was mixed with red stoneware atomized paste (RSAP) in varying proportions (5–30 wt%) and fired at temperatures between 1000 and 1200 °C. The volumetric expansion, density, and compressive strength of the resulting aggregates were determined via mineralogical and microstructural characterization. The results indicate the organic fraction's suitability as an expansion agent, particularly at 1200 °C with 5–15 wt% inclusion, showcasing density (0.65–0.75 g/cm3) and compressive strength (1.34–1.39 MPa) comparable to commercial expanded clays. The microstructural analysis revealed the formation of rounded pores, influenced by the firing temperature and OF content. A Life Cycle Assessment (LCA) compared the environmental impacts of this process with traditional LECA manufacturing, highlighting the potential environmental benefits of using recycled battery waste. This study marks the first incorporation of this battery waste residue into LECA manufacturing, providing valuable insights into its environmental implications and paving the way for sustainable waste management practices.

Transport Properties of Internally Cured Self Compacting Concrete with Fly Ash

Proper curing of concrete has a major beneficial effect on the transport properties of concrete which in turn influences its durability. This paper attempts to study the effect of fly ash on the transport properties of internally cured Self-Compacting Concrete specimens under ambient conditions. Two internal curing materials, Lightweight Expanded Clay Aggregates [LECA] and Superabsorbent Polymer [SAP] were chosen for the study. Properties such as sorptivity, resistance to chloride ion penetration and chloride ion migration specimens with varying percentages of fly ash replacement from 30% to 50% are presented under different curing conditions namely conventional curing, sealed curing with internal curing materials and ambient curing with internal curing materials. The results showed that the impermeability of concrete improved with an increasing percentage of fly ash replacements owing to the presence of internal curing water to improve hydration along with fly ash that moderates the heat of hydration and drying. The internal curing efficiency also improved with the increase in the percentage of fly ash replacement. Under ambient conditions, the mixes with fly ash above 45% replacement have shown very good mechanical and durability properties indicating a refined pore structure leading to enhanced transport properties.

Dynamic response of rock sheds to successive rockfall impacts using lightweight expanded clay aggregate (LECA) cushions: An experimental and numerical study

This study investigates the effectiveness of Lightweight Expanded Clay Aggregate (LECA) as a novel cushion material mitigating repeated rockfall impacts on reinforced concrete (RC) slabs in rock sheds. Small-scale impact tests and finite element simulations analyze LECA particle size, cushioning material, block shape, and impact energy level influence on the dynamic response and damage. Results show LECA outperforms sand in attenuating impact forces and transmitted loads under successive impacts, which indicates a better protection effect on the substructure. Smaller LECA particles lead to wider stress distribution angles, longer impact durations, and lower peak forces. Block shape significantly influences impact force, with higher unified nose factors increasing forces. LECA cushions exhibit a dynamic amplification factor less than 1, indicating reduced transmitted loads compared to sand. Under high-impact energy conditions, the LECA cushion limits RC slab deflection within the elastic limit across all block shapes, while sand exceeds the elastic limit, potentially leading to structural failure. LECA mitigates flexural cracking and redistributes loads more uniformly, reducing overall RC slab damage compared to sand. However, localized failure modes require further optimization. This study highlights LECA's potential for enhancing rock shed structural safety and resilience against severe rockfall events, providing insights for optimal mitigation strategies.

Carbon Footprints of a Conventional Norwegian Detached House Exposed to Flooding

Rehabilitating water-damaged structures in buildings results in increased material extraction and energy use, and, consequently, a higher carbon footprint of the housing industry. Despite its prevalence, quantifying the carbon footprint caused by water damage or flooding has not gained much attention. Thus, this study investigated the quantitative carbon footprint associated with rehabilitating flooding in a detached house caused by torrential rain. Three different construction methods of the house were looked at; a timber frame construction, a masonry variant made by concrete blocks of Lightweight Expanded Clay Aggregate (LECA), and an alternative with exterior walls composed of concrete-moulded Expanded Polystyrene (EPS) foam boards. A life-cycle assessment according to NS 3720 was used to investigate the carbon footprint (CO2eq.) of typical flooding in a detached building. Rehabilitating the flooding in a house with concrete-moulded boards resulted in a lower carbon footprint (2.45 × 103 CO2eq.) than rehabilitating the same flooding in a house with LECA masonry (7.56 × 103 CO2eq.) and timber frames (2.49 × 103 CO2eq.). However, the timber-frame house had the lowest total carbon footprint (2.95 × 104 CO2eq.) owing to their original low footprint. This study found that flooding significantly contributed to the carbon footprint of buildings and, therefore, the topic should be given attention when choosing a construction method and moisture safety strategy.

Physical and Mechanical Properties of Lightweight Expanded Clay Aggregate Concrete

Physical and Mechanical Properties of Lightweight Expanded Clay Aggregate Concrete

Ultrasonic Pulse Velocity and Mechanical and Physical Properties of Structural Geopolymer Concrete Containing Lightweight Expanded Clay Aggregates: Experimental and Computational Study

Ultrasonic Pulse Velocity and Mechanical and Physical Properties of Structural Geopolymer Concrete Containing Lightweight Expanded Clay Aggregates: Experimental and Computational Study

Performance of steel fibre reinforced lightweight aggregate concrete in fresh and hardened state

Abstract There is a growing interest in the manufacture of lightweight aggregate concrete (LWC) due to its low density, which is below 2000 kg/m3. However, the trade-off for the lower density is a reduction in strength, leading to a drop in crack resistance. Therefore, steel fibre inclusion was implemented to augment the crack resistance of lightweight concrete (LWC). Thus, the present study aims to examine the impact of steel fibre on both the workability and mechanical properties of lightweight aggregate concrete (LWC) that incorporates lightweight expanded clay aggregate (LECA). Three varieties of concrete were fabricated, namely normal weight aggregate concrete (NC), lightweight concrete (LWC), and steel fibre lightweight concrete (SFWLC). The SFLWC incorporated hooked-end steel fibres as reinforcement, with fibre volume percentages of 1 % and 2 %. A strength assessment was undertaken to ascertain the concrete properties, with particular emphasis on compressive and tensile strength. The findings indicate that the incorporation of both LECA and steel fibre led to a notable reduction in the workability of concrete. Incorporating a 2 % steel fibre content into LWC yields a marginal enhancement in compressive strength. Steel fibre demonstrates enhanced efficacy when subjected to tension, with the most significant increase measured at around 152 %.

Characteristics of Lightweight Concrete Fabricated with Different Types of Strengthened Lightweight Aggregates

The vast majority of different waste building units have negative environmental impacts around the world. Crushed building units can be recycled and utilized in the concrete industry to solve these problems and maintain natural resources. This study investigated the feasibility of employing crushed autoclaved aerated concrete (CAAC) and crushed clay brick (CCB) as a lightweight aggregate (LWA) to fabricate environmentally friendly recycled lightweight concrete (LWC). In addition, a lightweight expanded clay aggregate (LECA) was also used as an LWA, namely to study how the high porosity of an LWA can adversely affect the properties of LWC. Through the experimental program, all types of LWAs were pre-treated and strengthened with two cementitious grouts, and then the performance of the produced LWC was assessed by determining the slump of fresh concrete, the dry density, the unconfined compressive strength, and the splitting tensile strength at ages of 3, 7, 28, and 56 days. The laboratory results revealed that both CCB and CAAC can be reused as full substitutions for normal-weight coarse aggregate to manufacture LWC with appropriate properties. The obtained data show that the properties of an LECA, CCB, and CAAC were improved, and the porous structure can be strengthened by pre-treatment and coating with grouts. In the same way, the mechanical performance of produced LWC is also enhanced.

Production of lightweight expanded aggregates from smectite clay, palygorskite-rich sediment and phosphate sludge

Abstract Lightweight expanded clay aggregates (LWAs) are porous materials with low density and high strength (EN-13055-1), and they are important in sustainable construction through their lightweight nature and ability to provide thermal or acoustic insulation. The objective of this work was therefore to evaluate the preparation of LWAs using a smectite clay (M1 formulation), whose application in common ceramic production is difficult. An alternative approach was proposed for the valorization of phosphate sludge and a palygorskite-rich sediment by mixing them with expanded clay (M2 formulation) for LWA production. This could result in economically cost-effective products with significant environmental benefits. Pellets were prepared and fired at various temperatures (1100°C, 1125°C and 1150°C), and relevant properties such as bloating index, density, water absorption and compressive strength were determined. Additionally, the microstructure, mineralogical transformations and phase compositions under various sintering temperatures were investigated. Increasing the temperature from 1000°C to 1150°C significantly improved the expansion properties of LWAs, and 1150°C seemed to be the optimal firing temperature at which the best expansion properties were achieved. In addition, the incorporation of the selected waste improved the properties of the final products, leading to lower density, greater strength and greater bloating with the development of the internal pore structure as compared to the LWAs without this addition. Because of their low density (0.6 g cm–3) and sufficient compressive strength (0.86 MPa), the manufactured LWAs can be used in construction (as insulating panels or in lightweight concrete) and in green roofs.

EXPERIMENTAL STUDY ON LIGHTWEIGHT CONCRETE USING LECA MATERIALS

This study investigates the feasibility of incorporating Lightweight Expanded Clay Aggregate (LECA) materials into concrete to produce lightweight concrete with improved mechanical properties. The experimental approach involves varying proportions of LECA aggregate in concrete mixes and assessing their compressive strength, density, workability, and durability. Additionally, the study examines the effect of LECA aggregate on the thermal and acoustic properties of lightweight concrete. Results from the experiments demonstrate the potential of LECA as a viable lightweight aggregate in concrete production, offering insights into optimizing mix designs for enhanced performance and sustainability in construction applications.

Feasibility Study of Expanded Clay Aggregate Lightweight Concrete for Nonstructural Applications

In nonstructural infill panels, common materials like expanded polystyrene panels face fire susceptibility, autoclaved aerated concrete (AAC) incurs high production costs, and traditional bricks come with a significant carbon footprint and weight. So, there is a requirement for infill panels that are not just resilient and lightweight but sustainable as well. This study seeks to address these issues by introducing sustainable and lightweight expanded clay aggregate (ECA) in concrete. Firstly, eight ECA mix designs were prepared by integrating fly ash and kerosene with clay, and ECA with a bulk density of 0.59 g/cm³ and compressive strength of up to 1.73 MPa were prepared. The lightest ECA mix was then chosen to explore their use in lightweight aggregate concrete (LWAC) along with fly ash as a secondary cementitious material. The resulting LWAC had a minimum density of 1,050 kg/m³ and a compressive strength of 6.8 MPa, fulfilling the standard requirements of a minimum of 3.5 MPa for nonstructural concrete.

Thermal and mechanical properties of a sustainable bio-flax fibre-based lightweight aggregate concrete

A novel lightweight aggregate concrete (LWAC) or lightweight concrete (LWC) is developed using expanded perlite powder and lightweight expanded clay aggregate as a replacement for conventional fine and coarse aggregates, respectively. Furthermore, the natural plant-based flax fibre in treated form was added to the LWC mix at three different volume fractions. The mechanical and thermal characterisation of LWC was carried out using the compressive strength test, split tensile test, modulus of rupture, thermal conductivity and thermal resistance test. Moreover, the microstructural and durability properties were obtained using scanning electron microscopy/energy dispersive X-ray spectrum analysis, rapid chloride penetration test, sorptivity test and water absorption test. Test results reveal that the addition of 2.0% flax fibre resulted in improved mechanical, thermal and durability properties when compared to LWC with no fibres. Moreover, the microstructural analysis using SEM revealed the formation of ettringite which is responsible for the strength development in the LWAC mix.

An Innovative Sunlight‐Driven Device for Photocatalytic Drugs Degradation: from laboratory‐ to real‐Scale Application. A First Step Toward Vulnerable Communities

AbstractFreshwater represents one of the most precious resources on the planet, so it is fundamental to preserve it. In this work, an innovative sunlight‐driven device composed of bismuth oxybromide (BiOBr) grown on a material derived from natural sources, i.e., Lightweight Expanded Clay Aggregates (LECA), is developed to clean surface waters under natural solar light irradiation. For this purpose, the photodegradation of two non‐steroidal anti‐inflammatory drugs, ibuprofen, and diclofenac, is investigated under varying operative conditions. Laboratory‐ and real‐scale experiments reveal that the fabricated floating BiOBr/LECA photocatalyst fully degrades diclofenac, whereas limited abatement of ibuprofen is observed. Based on the identification of specific transformation products (TPs) during the degradation, this behavior seems to be strongly related to the different structures of the two drugs. In fact, the main TP produced during diclofenac degradation derives from dechlorination and ring condensation: this type of photocatalytic degradation pathway is generally favored over the C─C bonds's cleavage, which is a unique possibility for IBU abatement. Moreover, the potential partial adsorption of these species on the photocatalyst's active sites can cause their deactivation. Finally, reusability tests demonstrate the high stability of the floating composite.

Quality analysis of self curing concrete incorporated with lime coated light weight expanded clay aggregate (LECA)

Quality analysis of self curing concrete incorporated with lime coated light weight expanded clay aggregate (LECA)

Assessment of the Efficiency of Eco-Friendly Lightweight Concrete as Simulated Repair Material in Concrete Joints

The high production of carbon dioxide from concrete cement manufacturing and the high utilization of natural resources in concrete has been a concern for research in recent decades. Eco-friendly concrete (Eco-Con) is a type of concrete that uses less energy in its production, utilizes waste materials, produces less carbon dioxide, and is durable. This study assesses the efficiency of the proposed lightweight Eco-Con mixes with 32 MPa compressive strength in repairing different types of concrete structures. Rubber and lightweight expanded clay aggregate (LECA) were used as lightweight materials in the Eco-Con mixes. One Portland cement concrete mix (CC) and three different Eco-Con mixes, namely geopolymer rubber concrete (GR), geopolymer LECA concrete (GL), and rubber-engineered cementitious composite (RECC), were produced and compared. The concrete mixes were utilized as simulated ‘repair’ materials in several types of concrete joints, namely reinforced slab–beam joints (400 × 300 mm L-shape, 500 mm width, and 100 mm thickness) subjected to bending, concrete joints in beams (100 × 100 × 350 mm) subjected to bending, and concrete joints in unconfined and fiber-reinforced polymer (FRP) confined columns (100 mm diameter and 200 mm height) subjected to axial compression. The reinforced slab–beam joint and FRP-confined column joint were tested with two joint angles of 0° and 45°. The results indicated that RECC is an efficient lightweight Eco-Con alternative to Portland cement concrete in repairing concrete structural elements, especially beams and FRP-confined columns, as it increased their strength capacities by 43% and 190%, respectively. At the tested joint angles (0° or 45°), the use of Eco-Con mixes showed relatively lower slab–beam joint strength capacity than that of the CC mix by up to 14%. A joint angle of 45° was better than 0°, as it showed up to 7% better slab–beam joint strength capacity. Using shear connectors in slab–beam joints had adverse effects on concrete cracking and deformability.

Thermo- mechanical and microstructural characterization of LECA and low carbon cement based lightweight mortar using box behnken design, and embodied energy analysis

Lightweight aggregate mortar (LWAM) containing different kinds of supplementary cementitious materials (SCMs) has gained significant attention as a sustainable construction material. However, the behavior of this type of mortar at elevated temperature conditions, such as those encountered in fire events, remains largely unexplored. In this study, the effect of different temperatures (i.e. at 27⁰C, 110⁰C and 850⁰C) on the Thermo-mechanical and microstructural properties of LWAM containing low grade limestone slurry (LgLS), class- F fly ash (FA), and lightweight expanded clay aggregate (LECA) is investigated. LgLS and FA were replaced with ordinary Portland cement (OPC) in the range of 0–20%, and 0–30% by weight. River sand was replaced with LECA, ranging from 0% to 50% with an increment of 25% in river sand fractions. Along with this, statistical modelling and parametric optimization were done using Box Behnken Design (BBD) of Response Surface Methodology (RSM). Advanced characterization techniques such as- Field Emission Scanning Electron Microscopy (FE-SEM) and X-ray Diffraction (XRD) were performed to investigate the effect of higher temperatures on the microstructure and hydration products of LWAM matrix. Embodied energy analysis was also carried out to investigate the environmental assessment along with cost analysis. It was concluded that as compared to the reference LWAM mix at 27 °C; CS at 28 days was increased by 15–25% at temperature of 110 °C for different mixes, while the same was drastically decreased by 60–64% at higher temperature i.e. 850 °C. Embodied energy analysis predicted that carbon emission can be minimized by about 25%, which is the need of the recent era to meet sustainable development goals.

RHEOLOGY AS A TOOL FOR TECHNOLOGICAL ADVANCEMENTS IN SELF-COMPACTING LIGHTWEIGHT CONCRETE MIXES

This paper outlines a methodology aimed at enhancing the technological performance of self-compacting concrete using lightweight expanded clay aggregate. One of the primary challenges encountered when employing concrete with lightweight aggregate involves displacing expanded clay grains within the solution's liquid phase to ensure necessary fluidity (workability) while upholding high stability (structural viscosity and segregation resistance). To achieve this objective, the rheological parameters of the self-compacting cement matrix have been regulated by deliberately adjusting the functional groups of additives and the microfine mineral filler, employing analytical methods from computer materials science. Through the analysis of rheometric results obtained from investigating various solution mixtures, the most suitable model that describes their rheological behaviour has been identified. The impact of finely dispersed fly ash excipient, a carboxylate superplasticiser, and a stabiliser additive on the rheological parameters of self-compacting lightweight concrete mixes has been established. The inclusion of these complex additives in the composition has enabled substantial alterations in the flow index across a wide range (0,030-0,798). This adaptability allows for the adjustment of the mortar mixture's rheological behaviour throughout a spectrum ranging from «abnormally viscous liquid» to «Newtonian liquid». This approach, examining the singular-factor dependencies' analysis on the coefficients of rheological behaviour models, aids in addressing the primary challenge encountered when using concrete with lightweight aggregate.