Lightweight Fine Aggregate Research Articles

Effect and mechanism of phase change lightweight aggregate on temperature control and crack resistance in high-strength mass concrete

Under temperature stress, high-strength mass concrete is brittle due to its high total heat of hydration. In this study, a control mixture of C55 high-strength mass concrete meeting the performance requirements was prepared. The effects of different functional aggregates on the thermal properties, such as setting and hardening rate, peak temperature, and temperature rise and fall rate in the early stage of cement hydration, as well as the effects of functional lightweight aggregates on the workability, mechanical properties, and deformation properties of concrete, were investigated in this paper using two types of aggregates with thermal insulation and phase change energy storage functions. The study shows that, in addition to having some early strength impacts and temperature management capabilities, thermal storage coarse lightweight aggregate (PCCLA) and thermal insulation fine lightweight aggregate (TIFLA) can both increase the workability and crack resistance of concrete. When it comes to temperature regulation, thermal storage coarse aggregate outperforms thermal insulation functional aggregate significantly. Thermal insulation fine aggregate can improve the rate of setting and hardening, while coarse thermal storage aggregate may work as in-situ self-heating curing in the early stages due to its phase change energy storage. This quickens the rate of setting and hardening and increases the resistivity of the set period, which in turn increases the rate of drying shrinkage.

Microstructure, XRD, and strength performance of ultra-high-performance lightweight concrete containing artificial lightweight fine aggregate and silica fume

Ultra-high-performance lightweight concrete (UHPLC), a sustainable and environmentally friendly concrete crafted with artificial lightweight aggregates to preserve non-renewable natural resources like river sand, has garnered significant attention due to its exceptional mechanical properties. This study explores the use of artificial lightweight fine aggregate (ALWFA) as a substitute for fine aggregate in UHPLC production, investigating both fresh properties and mechanical performance. Microstructure analysis, utilizing SEM, and crystalline phase evaluation, employing XRD, were also conducted. The study results indicated that due to the irregular shape of ALWA particles with sharp edges, increasing the content of ALWFA led to a reduction in the flowability of UHPLC. Additionally, it was found that increasing the amount of ALWFA as a replacement for fine aggregate negatively affected both the compressive and tensile strength of UHPLC. This reduction in strength can be attributed to the higher porosity and lower intrinsic strength of ALWFA particles, as well as the weaker cohesion between ALWFA particles and the matrix. SEM analysis revealed that elevating the ALWFA content as a replacement for fine aggregate resulted in an increase in both the number and dimensions of voids, which is responsible for the weaker performance of ALWFA concrete. Finally, XRD analysis showed no significant alteration in the crystalline phases as the ALWFA content increased.

3D-printed LC3-based lightweight engineered cementitious composites: Fresh state, harden material properties and beam performance

3D concrete printing (3DCP) technology has undergone rapid development and is poised to emerge as a crucial component of intelligent construction due to its expeditious construction process and efficient material utilization. Integrating 3DCP with engineered cementitious composites (ECC) enables self-reinforced construction without placing steel bars. However, the environmental impacts associated with ordinary Portland cement-based printable ECC impose challenges to sustainable development. This study investigates a sustainable ECC for 3DCP applications with the integration of limestone calcined clay cement (LC3) and lightweight fine aggregate. A systematic study of the innovative 3D-printable LC3-based lightweight engineered cementitious composites (LL-ECC) from fresh state to hardened state, accompanied from material level to component level was conducted. The printable mixture was designed through the optimization of the fresh properties of LL-ECC with different fiber contents. The mechanical properties of hardened LL-ECC demonstrated competitive or even superior mechanical performances compared to mold-cast counterparts, including compressive properties, fracture toughness, and shear strength. Moreover, the printed LL-ECC beams exhibited excellent flexural strength and ductility with increase of approximately 40 % and 100 % than mold-cast beams, respectively. LL-ECC further exhibited significant reductions in material cost, embodied energy and carbon footprint, and higher specific strength compared to those of traditional OPC-ECC. Therefore, LL-ECC is a high-performance and promising composite with balanced printability, mechanical properties, and sustainability in 3D printing.

Impact of fine lightweight aggregates and coal waste on structural lightweight concrete: Experimental study and gene expression programming

Light Expanded Clay Aggregate (LECA) is one of the materials used to make lightweight concrete. In this study, two types of lightweight aggregates including LECA in both coarse and fine aggregate forms and pumice in fine aggregate form have been used to produce lightweight aggregate concrete. Coal waste is also used as partial replacement for cement. The results show that the usage of pumice as partial replacement for sand and LECA as coarse aggregate is applicable and can used for producing structural lightweight aggregate concrete. Furthermore, by using and increasing in the amount of LECA as fine aggregate, the slump of lightweight concrete in comparison to using sand, is also increased. The mixtures with LECA in both fine and coarse aggregate forms have the best results. Also, the results show that adding the coal waste improves the properties of lightweight concrete, and the optimal ratio is about 15% as partial replacement for cement by weight. In addition, gene expression programming is employed to establish empirical connections derived from experimental outcomes. In this regard, a relationship is proposed to determine the compressive strength of lightweight aggregate concrete based on the experimental data. The outcomes of gene expression programming demonstrate that the suggested formula exhibits good accuracy and efficiency in forecasting the specified parameter.

Compaction Delay and Temperature Effects on Early-Age Properties of Roller-Compacted Concrete

The lower water content of roller-compacted concrete (RCC) coupled with climatic conditions (e.g., higher air temperature, increased wind speed, and lower relative humidity) and compaction delay factors (e.g., traffic delay, plant location, and paving speed) can significantly affect the in situ density and hardened properties of RCC pavements. In this study, a control RCC mix was batched and maintained at standard (21°C) and elevated (35°C) temperatures and then compacted at increasing delay times for up to 180 min. The elevated mix temperature and compaction delay times greater than 90 min prevented the RCC mix from achieving 98% of the initial wet density from the modified Proctor test. Two additional RCC mixes were batched to determine if they could maintain a longer compaction window, one containing a rheology-modifying and retarding admixture and the other incorporating saturated fine lightweight aggregates. The RCC with admixture was the most effective at maintaining moisture content, density, compressive strength, and fracture properties at all compaction delay times. For example, at 180 min of delay, the RCC mixture with admixture still maintained 98.2% of the initial wet density, 81% of the compressive strength, and approximately the same fracture toughness and energy. The addition of fine lightweight aggregates did not extend the compaction window relative to standard RCC mix. The gyratory compacted specimens were more sensitive to the effects of temperature and compaction delay on RCC mixes than the vibratory hammer prepared specimens.

Study on the Pore Structure of Lightweight Mortar with Nano-Additives.

With the development of nanotechnology, nanomaterials have been introduced to improve the engineering properties of cement-based building materials. An abundant number of studies have been carried out on normal-weight concrete using multi-walled carbon nanotubes (MWCNTs) or nano-silica (NS) and have proven their effectiveness. Nevertheless, still very few investigations are available in terms of lightweight cement-based materials, especially when MWCNTs and NS are binarily incorporated. Thus, in this study, fly ash cenospheres (FACs) according to cement weight were applied as lightweight fine aggregates to produce lightweight mortar (LWM). MWCNTs at 0.05, 0.15, and 0.45% and NS at 0.2 and 1.0% were binarily added as modifiers. Compressive and flexural strengths were tested to investigate mechanical behaviors. A water absorption test was conducted, together with scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), to identify the impacts of the nano-additives on the pore structure of LWM. The following results were obtained: MWCNTs and NS demonstrated synergic effects on enhancing the mechanical properties of LWM. MWCNTs exerted positive impacts on reducing the porosity and improving the pore distribution at low dosages of 0.05 and 0.15%. The hybrid addition of NS further transformed large voids into small ones and introduced closed pores.

MECHANICAL PROPERTIES OF SUSTAINABLE FIBER-REINFORCED LIGHTWEIGHT AGGREGATE CONCRET

With the rapid growth of high-rise buildings and large-scale structures, there is a need to preserve natural resources and reduce loads on buildings by using lightweight concrete to achieve better performance for structures. In the study, four groups were prepared; the first group included one mix containing natural aggregate, and the second mix replaced all the natural aggregates with lightweight pumice aggregates. These mixes are reinforced with carbon fiber with a 0.5% volume fraction. In the second group, a variable volume fraction of carbon fiber of (0.0 and 1%) of mixes. In the third group, the mixes have different lengths of carbon fiber (20mm, 30mm) and a volume fraction of carbon fibers 0.5%. Finally, the fourth group partially replaces sand as a variable with a percentage of lightweight fine aggregates (10% and 30%) reinforced with fibers. Adding carbon fibers to the concrete specimens by 0.5% and 1% improved splitting tensile strength and flexural strength compared to the specimens containing carbon fibers with a length of 5mm. Also, enhanced samples containing fibers by 0.5% and lengths of 20 mm or 30 mm, compared to the sample containing carbon fibers with a length of 5 mm. Also, the specimens containing lightweight fine aggregates as a replacement with a percentage of sand have a lower splitting tensile strength and flexural strength than the reference mix.

Some properties of thermal insulating cement mortar using Ponza aggregate

Abstract Lightweight aggregate (LWA) mortar is made using lightweight or low-density aggregate, which improves properties such as thermal insulation, durability for freezing and thawing, fire and temperature resistance, and sound insulation. This research aims to use lightweight fine aggregate obtained from crushing natural rocks that are locally called “Ponza” to produce LWA mortar with different mix proportions to study the possibility of using it to produce blocks that can be erected on the outer side of the walls of old buildings to provide good thermal insulation. It also presents a study about the internal curing property of the produced cement mortar, which comes from the absorbed water by the used surface-saturated dry Ponza aggregate. The process includes using three mix proportions (1:1, 1:0.7, and 1:0.5) by weight of cement: fine aggregate. The samples were cured by dividing them into five groups, including moist curing for 1, 3, 7, and 28 days and the fifth group was moist cured for 1 day and then covered by a thin layer of flan coat. Dry density, compressive strength, flexural strength, and thermal conductivity for ages (7, 28, and 56 days) have been tested. The findings indicate that it is possible to produce thermal insulating lightweight cement mortar with mixtures of 1:0.7 or 1:0.5 cement to LWA, using Ponza aggregate, since the results showed an acceptable range of compressive and flexural strengths reaching about 14.75 and 2.91 MPa, respectively, a bulk density of less than 1,600 kg/mm3, and a lower thermal conductivity than many building materials.

Workability Properties of Specified Density Concrete with Municipal Solid Waste Incinerator Tailings Added as a Lightweight Aggregate

The application of municipal solid waste incineration tailings lightweight aggregate (MSWI-TLA) for reducing carbon emissions, energy consumption, and environmental pollution of bulk solid waste treatment has received extensive attention. As a new type of green lightweight aggregate, MSWI-TLA exhibits considerably good performance and broad prospects; however, its working performance in cement-based materials is not as good as that of ordinary aggregates. In this study, a standardized municipal solid waste incineration tailings lightweight fine aggregate (MSWI-TLFA) with a fineness modulus of 3.1 and a municipal solid waste of 10 mm were utilized as substitutes for the common aggregate. The incineration tailings lightweight coarse aggregate (MSWI-TLCA) with the particle size ranging from 5 to stirring process and the fluidity and filling properties were improved, and stratification was slowed down. Based on the slump, fluidity, and stratification data of municipal solid waste incineration tailings lightweight aggregate specific density concrete (MSWI-TLA-SDC), the internal and external stacking structure model, matrix density three-phase diagram, and stratification function relationship were established, and the formation mechanism of fluidity and homogeneity under the synergistic effect of MSWI-TLA-SDC matrix density was revealed. Simultaneously, the qualitative analysis of homogeneity was carried out intuitively and visualized using computed tomography (CT) technology, and the accurate quantitative analysis model of stratification degree and aggregate separation factor was established using the principle of fluid mechanics, and the optimization effect was verified. The results show that the fluidity of MSWI-TLA-SDC decreases by 3.3%–30.5% and the delamination degree increases by 4.9%–22.9% compared with ordinary concrete. The main reason for the poor fluidity and homogeneity of MSWI-TLA-SDC is the poor density synergy between tailings lightweight aggregate, ordinary aggregate, and mortar matrix. The preabsorbed gravel-type small-size tailings lightweight aggregate along with technical measures like combining water-reducing agent, fine tailings aggregate, and tailings powder can be used to reduce the difference in matrix density and fully exploit the synergistic effects of matrix density. For the closed-loop absorption of tailings lightweight aggregate as well as the technical advancement and promotion of MSWI-TLA-SDC, it is crucial to increase the fluidity and homogeneity of MSWI-TLA-SDC.

Study on dynamic properties of lightweight ultra-high performance concrete (L-UHPC)

Ultra-high performance concrete (UHPC) is being considered as a potential material for concrete structures subject to impact and blast loads due to its exceptional strength and ductility characteristics. In this study, a lightweight ultra-high performance concrete (L-UHPC) was developed using fine lightweight aggregate. To further understand the mechanical response of L-UHPC at high impact velocities, the dynamic properties (such as failure pattern, peak stress, DIF, stress–strain curve, and toughness) of L-UHPC were investigated and the effect of steel fiber type on dynamic properties was analyzed. According to the research findings, the L-UHPC exhibits significant sensitivity to variation of strain rate, it experiences more damage, exhibits a higher peak stress, and absorbs more energy when subjected to a higher strain rate. The steel fiber shape exhibited little effect on both quasi-static and dynamic properties. Furthermore, an empirical formulate of dynamic increase factor (DIF) for L-UHPC with different steel fiber was proposed. At last, the failure mechanism of L-UHPC was analyzed. The experimental findings can provide a valuable reference for the further understanding and studying the dynamic characteristic of concrete with ultra-high strength and low density.

Engineering particle size distribution of sintered lightweight aggregates manufactured from waste coal combustion ash

Converting waste coal combustion ash (W-CCA) from power plants into novelty lightweight aggregates (LWA) is a viable and sustainable solution. Utilizing this waste material to produce a useful product for the concrete industry requires that the manufactured LWA adhere to industrial material regulations. This study focuses on engineering laboratory manufactured LWA to achieve aggregate gradation that meets the ASTM C330 standard. A systematic study that manipulates the degree of saturation during W-CCA paste preparation was adopted to understand the effect of moisture on LWA gradation. The degree of saturation was assessed based on the liquid (water) to solid ratio required to manufacture W-CCA paste. The investigation only alters the amount of water and recorded the gradation for fine LWA (FLWA), coarse LWA (CLWA), and combined coarse and fine LWA. L/S ratio of 0.33 achieved ASTM C330 required gradation for FLWA. A combination of L/S ratio of 0.33 and 0.34 achieved ASTM C330 required gradation for combined coarse and fine LWA. Engineering the gradation of LWA to meet ASTM required standard will allow the production of LWA from W-CCA a more attainable and practical product for the construction industry.

Geopolymer Concrete with Lightweight Fine Aggregate: Material Performance and Structural Application

Limited information and data are available on the material and structural performance of GC incorporating lightweight fine aggregate. In this research, three types of lightweight fine materials were utilized to partially replace sand volume of GC. These lightweight materials were rubber, vermiculite, or lightweight expanded clay aggregate (LECA) and they were used in contents of 20%, 40%, 60%, and 100%. The variables were applied to better investigate the efficiency of each lightweight material in GC and to recommend GC mixes for structural applications. The concrete workability, compressive strength, indirect tensile strength, freezing and thawing performance, and impact resistance were measured in this study. In addition, three reinforced concrete slabs were made from selected mixes with similar compressive strength of 32 MPa and then tested under a 4-point bending loading regime. The results showed that using LECA as sand replacement in GC increased its compressive strength at all ages and all replacement ratios. Compared with the control GC mix, using 60% LECA increased the compressive strength by up to 44%, 39%, and 27%, respectively at 3, 7, and 28 days. The slabs test showed that partial or full replacement of GC sand adversely affected the shear resistance of concrete and caused premature failure of slabs. The slab strength and deflection capacities decreased by 9% and 30%, respectively when using rubber, and by 23% and 59%, respectively when using LECA, compared with control GC slab. The results indicated the applicability of GC mix with 60% LECA in structures subjected to axial loads. However, rubber would be the best lightweight material to recommend for resisting impact and flexural loads.

Self-healing properties of lightweight high-toughness cementitious composites under dry-wetting cycles

Lightweight high-toughness cementitious composites (LHTCC) were induced to produce pre-cracks through bending and tensile loads, which were self-healed under dry-wetting cycles. Cementitious composites used silica sand as fine aggregate and without aggregate were used as the reference group to explore the influence of cenospheres as lightweight fine aggregate on the self-healing properties. The self-healing properties were evaluated with bending properties, tensile properties and capillary water absorption. The composition of healing products was tested by X-ray diffraction and thermo-gravimetric analysis. The results indicated that cenospheres effectively improved the self-healing ability of LHTCC compared with silica sand as fine aggregate. The flexural strength and ultimate deflection of the self-healed specimens were increased by 32.2% and 118.5%, respectively, compared with the original specimens. The self-healing products filled the cracks and pores of the specimens, thus significantly decreasing the sorptivity coefficient. The addition of cenospheres promoted the consumption of calcium hydroxide to generate calcium silicate hydrate and calcium carbonate crystals with a dense microstructure, thereby increasing the flexural strength and toughness of LHTCC after self-healing. Therefore, LHTCC integrate the advantages of lightweight, high toughness and self-healing ability, and it is expected to be an ideal choice for concrete structures.

Improving the effectiveness of internal curing through engineering the pore structure of lightweight aggregates

A low absorption rate and a small thermal conductivity coefficient are the main targets in the preparation of traditional coarse lightweight aggregate (LWA). Fine LWA is generally used as internal curing materials and crushed from coarse LWA. Large pores or low water absorption will reduce the effectiveness of internal curing. In this study, a waste-based fine LWA with high water absorption (≥20%) has been made of bauxite tailings, silica fume, and paper sludge. The pore structure formation of fine LWA was analyzed. Time-dependent water absorption, water desorption, and pore structure of fine LWA were tested. Their effects on the early-aged hydration, autogenous shrinkage, pore structure, and compressive strength of high-strength mortars were studied. The results showed that different from the isolated and large pore structure of the expanded shale, fine LWA had a connected and fine pore structure of 200–2000 nm. It could absorb about 30.6% water by mass and quickly reaches saturation, and more than 95% of water absorbed was released at 97% relative humidity (RH). Fine LWA had a good water retention capacity and did not result in the delay of the main hydration. The capillary pore size of 20–50 nm increased and the total porosity reduced due to the increased degree of hydration. Compared to the high-strength mortars with the same mixing water content, fine LWA reduced the autogenous shrinkage of mortars by up to 88% and increased the strength of mortars by up to 2.5%.

Use of bauxite tailing for the production of fine lightweight aggregates

The prediction of bloating of lightweight aggregates (LWA) made from waste materials according to the chemical composition of raw material does not provide a good fit with existing theories. To explain the pore formation of LWA more accurately, it is necessary to consider the effect of initial voids due to gas release before the generation of the liquid phase. This study utilized the bauxite tailing and silica fume as raw material and a two-step firing method to produce fine LWA. The basic properties and microstructure of LWA were evaluated. The experimental results showed that bauxite tailing and silica fume played different roles in the pore formation of LWA. Bauxite tailing can provide gas-generating components related to the initial voids. Silica fume can promote the generation of the liquid phase associated with the development of closed pores. The LWA produced from bauxite tailing and silica fume had a bulk density of 931–1100 kg/m3 and water absorption of 1.2–16.6%, which met the specification standard for LWA. Silica fume of above 20% and sintering temperature of above 1100 °C could produce LWA applied in lightweight concrete and insulation wall panels, while silica fume of below 20% and sintering temperature of below 1100 °C could produce LWA for internal curing. In a word, it was possible to achieve the bloating of LWA by controlling the amount of gas released using the two-step firing method. Introducing the concept of initial voids can lead to the successful design and production of functional LWA having desirable engineering properties for different industrial applications.

Effect of multi-minerals on the mechanical behavior and pore structure of fiber reinforced internal-cured green concrete

In this study, multi-minerals were incorporated in fiber reinforced internal-cured green concrete (FRICC) to achieve both an improvement in concrete performance and environmental sustainability. The effect of multi-minerals on FRICC with pre-wetted lightweight fine aggregate (LWFA) and basalt-polypropylene (BF-PF) fiber was investigated through examining compressive and flexural strengths, flexural toughness, microstructure, pore structure and CO2 emissions. In comparison to ordinary concrete (mixture PO), FRICC presented good flexural performance but a decreased compressive behavior with an increase of 20.5% in flexural strength and a minor decrease of 1.6% in compressive strength. With the addition of multi-minerals, an enhancement in fiber-strengthening and anti-cracking performance was achieved, presenting a positive effect on concrete's strengths, post-cracking manner and pore structure. The internal curing of pre-wetted LWFA stimulated the pozzolanic reaction of minerals given that a denser microstructure with less porosity and more C–S–H gel effectively bound with aggregates and BF-PF fiber was identified. FRICC with a ternary mix of minerals (10% fly ash, 10% blast furnace slag and 5% metakaolin) exhibited the best mechanical performance and pore structure with an increase of 19.6% and 19.2% in compressive and flexural strength, respectively, and a decrease of 29.3% and 13.6% in porosity and mean pore diameter, respectively. Additionally, a reduction in CO2 emissions of up to 19.7% was achieved through adding multi-minerals. In general, the incorporation of multi-minerals brings positive consequences to both the performance of FRICC and environmental sustainability.

Strategy for preventing explosive spalling and enhancing material efficiency of lightweight ultra high-performance concrete

The highly dense structure which causes the risk of explosive spalling is one of the major limitations of using ultra high-performance concrete (UHPC). This study developed a lightweight UHPC (L-UHPC) and proposed a strategy to improve its material efficiency and lower the risk of explosive spalling. High-strength hollow glass microspheres and fine lightweight aggregates were jointly used in the UHPC system to achieve light weight and ultra high strength. The L-UHPC was cured at different curing regimes to maximize its material efficiency and prevent its spalling after exposure to high temperature. The experimental results showed that the combination of lightweight materials and dry heat curing was effective in reducing the density (<1800 kg/m3) and enhancing the compressive strength (>150 MPa) of the L-UHPC. By means of minimizing the amount of internal free water, the heat curing approach contributed to avoiding the thermal spalling of the L-UHPC exposed to fire conditions. Microstructural results indicated that the elevated temperature curing promoted the pozzolanic reaction and increased the microhardness of the paste matrix by increasing silicate polymerization of the C-S-H structure. The created voids of the collapsed glass microspheres might accommodate some internal vapor pressure and mitigate the degradation caused by the high temperature exposure. The synergetic effect of the porous materials and the dry heat curing lowered the thermal conductivity and significantly improved the material efficiency of the L-UHPC.

Improve the long-term property of heat-cured mortars blended with fly ash by internal curing

Due to the satisfactory property and high productivity, heat-cured concretes have been widely used in engineering practice. However, heat curing process also brings some drawbacks that are detrimental to the long-term property of this material. To address this issue, lightweight fine aggregate (LWFA) was employed to provide internal curing (IC) for a heat-cured mortar (HCM) blended with fly ash (FA). The influences of LWFA on the interior relative humidity of HCM and the reaction environment and behavior of FA were measured. It was found that IC of LWFA could mitigate the drop of interior humidity and enhance the reaction degrees of cement and FA. This contributed significantly to the microstructure densification of HCM, higher compressive strength and better resistance to chloride ion. The results indicate that LWFA benefits to enhancing the efficiency of FA in a heat curing system and the combination of LWFA and FA contribute to improving the long-term property of HCM.

Compressive strength prediction of structural lightweight concrete by applying the recurrent neural network‐fractional order bat optimization algorithm

AbstractNeural networks methods produce an analysis in various fields. The Neural Network is frequently employed for developing statistical methods for nonlinear systems since, the Neural Networks use the simulation benefits of complicated behavior in several problems. In this study, the Recurrent Neural Network and Recurrent Neural Network based on Fractional Order Bat Optimization Algorithm is utilized for predicting the compressive strength of Lightweight Concrete mixes in 3, 7, 14, and 28 days curing. Recurrent Neural Network has been used for having a comparison. The inputs to the network for the compressive strength are made of eight variables: sand, lightweight fine aggregate, water to cement ratio, silica fume utilized in solution, Lightweight course aggregate, silica fume utilized supplementary to cement, curing period, and superplasticizer. According to the results, the Recurrent Neural Network based on Fractional Order Bat Optimization Algorithm has predicted precise outcomes and trained so fast in comparison with RNN method.by considering the outcomes, the Neural Networks methods are satisfactory mechanisms to evaluate the LWC compressive strength. This can decrease the price and reduce the time of processes in these problems.

Evaluation of Compressive and Tensile Strength of Self-Curing Concrete by Adding Crushed Bricks as Additive Material

Curing is an essential stage in the production of concrete because it controls cement hydration and strength evolution. One of the methods of curing is the internal or self-curing which can be achieved by using materials of specific characteristics inside concrete to provide moisture from within the concrete as opposed to outside of it. This water should not affect the water-cement ratio. Lightweight coarse or fine aggregate or using absorbent polymer particles with an ability to keep water inside the concrete mixture can be used for this purpose. This study presents the use of crushed brick as a curing agent and evaluate its effects on the compressive and tensile strengths of concrete at different ages. Four mixes were used: M0, M10, M20, and M30. All the aggregates in mix M0 are natural gravel, while mixes M10, M20, and M30 contain 10%, 20%, and 30% crushed bricks, respectively, as replacement of coarse aggregate. The tests results showed that using crushed brick as a self-curing agent gave compressive strength up to 87.8% and splitting tensile strength up to 169% compared to water-cured concrete.