High Strength Lightweight Aggregate Concrete Research Articles

A novel foaming-sintering technique for developing eco-friendly lightweight aggregates for high strength lightweight aggregate concrete

To address the scarcity of natural aggregates and reduce energy consumption in the concrete industry, a sustainable lightweight aggregate (LWA) was prepared with a self-foaming and sintering method by utilizing waste glass powder as the primary precursor and incineration bottom ash as a foaming agent. The effect of NaOH content (0 M, 2 M, and 8 M) on the physical properties of LWA was investigated. Replacing manufactured sand with sintered LWA (0 M-LWA and 2 M-LWA) by 50 vol% and 100 vol% to investigate their impact on the physical properties, mechanical properties, shrinkage, and alkali-silica reaction of high strength LWA concrete. The high strength LWA concrete prepared with 0 M-LWA possessed a density of 2127 kg/m3 and compressive strength of 108.7 MPa, which were slightly lower than that with manufactured sand. Due to the porous and lightweight nature of 2 M-LWA, the density and compressive strength of LWA concrete significantly decreased with the increased 2 M-LWA volume. Nevertheless, 100%-2M showed satisfying density of 1835 kg/m3 and compressive strength of 50 MPa. The internal curing effect of 2 M-LWA effectively mitigated the autogenous shrinkage of LWA concrete. The alkali-silica reaction expansion of all LWA was innocuous.

Development of high-strength lightweight concrete by utilizing food waste digestate based biochar aggregate

The application of carbon-negative biochar in cement composites can effectively reduce carbon emissions of construction materials. In this study, low-carbon composites were tailored with high volume of food waste digestate (FWD) biochar aggregate. The biochar was customized at different temperatures with the goal of enhancing the properties of cement-based composites. Backscattered electron microscopy (BSEM) images show that FWD biochar with a grey circle shape exhibited strong bonding with the cement matrix. Nano-indentation results indicate that the two statuses of FWD biochar showed visco-elastic and elastic-plastic modes of deformation, respectively. The FWD biochar aggregate prepared at higher pyrolysis temperatures (i.e., 650 °C and 750 °C) has higher elastic modulus (up to 11.4 GPa), which can be applied to make biochar blocks with higher strength and lower density compared to the biochar pyrolyzed at 550 °C. As a result, FWD 750BC blocks could reach 28-d compressive strength of 57.8 MPa and density of 1.77 g cm−3, which fulfilled the requirements of high-strength lightweight aggregate concrete. Hence, this study established a foundation to utilize FWD biochar as an aggregate in high-strength biochar construction materials.

Shrinkage prediction model of high strength lightweight aggregate concrete based on relative humidity

Concrete shrinkage affects the overall stability and long-term service performance of the structures. Lightweight aggregates (LWAs) with a porous structure are an ideal internal curing material to mitigate concrete shrinkage. Nevertheless, the low elastic modulus of LWAs has a negative impact on concrete shrinkage. In order to clarify the influences of LWAs in the high strength lightweight aggregate concrete (HSLC) on its shrinkage performance, the compressive strength, internal relative humidity (IRH), elastic modulus, and autogenous shrinkage (AS) of HSLC were analyzed experimentally in this study. The correlation of these parameters was investigated. As indicated by the results, compressive strength and elastic modulus were negatively related to the content of LWAs. The 28-day AS and IRH of HSLC and the critical moment of IRH increased by 3.9%, 20.2% and 36 h, respectively, when the content of LWAs increased from 0% to 100%. A linear relationship between AS and compressive strength and an exponential relationship between AS and IRH were established. Additionally, a shrinkage prediction model considering IRH of concrete and water absorption by LWAs was proposed for HSLC.

Effect of Graphene Oxide on compressive strength of Shale Ceramsite high strength lightweight aggregate concrete

The use of shale ceramsite to produce high-strength lightweight concrete (HSLWC) in the construction industry is an effective method for sustainable development and environmental protection. The growing demand for HSLWC has stimulated the development of nanomaterials to further enhance mechanical properties. This study investigated the effect of graphene oxide (GO) on the properties of HSLWC with shale ceramsite as a coarse and fine aggregate, including workability, density, compressive strength, and energy dispersive spectrometer (EDS) test. The control mixture was designed according to the standard of grade 40 high strength concrete, and four groups of mixtures were prepared by adding doses of GO at 0.00%, 0.02%, 0.04% and 0.06% by weight of cement to the control mixture. The experimental results showed that HSLWC with the 28-day compressive in the range of 43-54 MPa and the oven dry density of 1705-1783 kg/m3 could be produced by using shale ceramsite and shale pottery sand as coarse aggregate and fine aggregate, respectively. Simultaneously, adding a low content of GO to HSLWC could slightly increase the density, rationally reduce the slump, and significantly enhance the compressive strength. The EDS results showed that the reason for the increase in compressive strength was that GO could accelerate the cement hydration process and regulate the crystal morphology of the cement.

Flexural fatigue behavior of hybrid steel-polypropylene fiber reinforced high-strength lightweight aggregate concrete

Compared with ordinary concrete, high-strength lightweight aggregate concrete (HSLC) can remarkably attenuate self-weight in engineering structures. However, the fatigue performance of ordinary concrete is better than that of HSLC. Herein, the flexural fatigue behavior, including fatigue life and crack propagation process, of hybrid fiber (HF) reinforced HSLC under different stress levels (S = 0.85, 0.80 and 0.75) was investigated. A further analysis on the fatigue life and crack propagation rate of HF reinforced HSLC was also conducted by two-parameter Weibull distribution (2PWD) and Paris law, respectively. The results indicated that the fatigue life of all specimens followed the 2PWD under various stress levels. Compared to the single fiber reinforced HSLC, the HF reinforced HSLC exhibited minimum crack propagation rates, the longest duration of stable development stage and fatigue life. The fatigue life equation was established with double logarithmic fatigue equation by considering failure probability. Furthermore, the expression of crack propagation rate with respect to crack length of each group of specimens was proposed under various stress levels.

Shrinkage Prediction Model of High Strength Lightweight Aggregate Concrete Based on Relative Humidity

Shrinkage Prediction Model of High Strength Lightweight Aggregate Concrete Based on Relative Humidity

Compressive strength prediction of high-strength oil palm shell lightweight aggregate concrete using machine learning methods.

Promoting the use of agricultural wastes/byproducts in concrete production can significantly reduce environmental effects and contribute to sustainable development. Several experimental investigations on such concrete's compressive strength ([Formula: see text]) and behavior have been done. The results of 229 concrete samples made by oil palm shell ([Formula: see text]) as a lightweight aggregate ([Formula: see text]) were used to develop models for predicting the [Formula: see text] of the high-strength lightweight aggregate concrete ([Formula: see text]). To this end, gene expression programming ([Formula: see text]), adaptive neuro-fuzzy inference system ([Formula: see text]), artificial neural network ([Formula: see text]), and multiple linear regression ([Formula: see text]) are employed as machine learning ([Formula: see text]) and regression methods. The water-to-binder ([Formula: see text]) ratio, ordinary Portland cement ([Formula: see text]), fly ash ([Formula: see text]), silica fume ([Formula: see text]), fine aggregate ([Formula: see text]), natural coarse aggregate ([Formula: see text]), [Formula: see text], superplasticizer ([Formula: see text]) contents, and specimen age are among the nine input parameters used in the developed models. The results show that all [Formula: see text]-based models efficiently predict the [Formula: see text]'s [Formula: see text], which comprised [Formula: see text] agricultural wastes. According to the results, the [Formula: see text] model outperformed the [Formula: see text] and [Formula: see text] models. Moreover, an uncertainty analysis through the Monte Carlo simulation (MCS) method was applied to the prediction results. The growing demand for sustainable development and the crucial role of eco-friendly concrete in the construction industry can pave the way for further application of the developed models due to their superior robustness and high accuracy in future codes of practice.

Experimental study on axial compression for composite hollow column of steel fiber, high-strength lightweight aggregate concrete and angle steel

In order to study the axial compression performance for composite hollow column of steel fiber, high-strength lightweight aggregate concrete and angle steel, the axial compression tests were carried out on five composite hollow columns of steel fiber, high-strength lightweight aggregate concrete and angle steel with the variation parameters of hollow ratio (0%, 15%, 16%, 32% and 36%) and the form of opening (round hole and square hole). The failure phenomena and failure forms of the specimens were observed, and their stress–strain curves were measured, and the axial bearing capacity formula suitable for composite hollow column of steel fiber, high-strength lightweight aggregate concrete and angle steel was established. The following conclusions may be obtained from the test results: the axial compression performance for the composite hollow columns of angle steel is influenced by the hollow ratio and opening form greatly. The axial compression performance for composite hollow columns of steel fiber, high-strength lightweight aggregate concrete and angle steel is almost close to that of composite solid columns when the hollow ratio is low; The higher the void ratio, the more the cracks at the surface of the concrete, some transverse cracks appear, the peak load decreases by about 5–38%, and the deformation ductility coefficient increases gradually; The deformation ductility coefficient of round-hole hollow column is lower than that of square-hole hollow column. Based on the test, the finite element software ABAQUS is used to simulate the SCAH column. The correctness of the model is verified via the comparison between the numerical simulation results and the test results. At the same time, the stress nephogram of concrete and steel at different stages and the stress nephogram at concrete restraint state are simulated. According to the finite element simulation results, Mander model is used to calculate the axial compression bearing capacity of composite hollow column of angle steel. The high calculation accuracy and suitable for popularization can be obtained.

Bond-slip behaviors of composite steel-reinforced high strength lightweight aggregate concrete columns with innovative X-shaped steel sections

This paper provides an insight into the bond-slip performance of the new type of steel-reinforced high strength lightweight aggregate concrete (SRLWAC) column with innovative X-shaped steel sections through experimental and theoretical studies. Three SRLWAC specimens were tested under push-out force; the variables are the confinement by stirrups (ρsv) and shear connectors (SCs). Force-slip curves, force axial and horizontal deformations, failure modes, and crack patterns of the specimens were investigated; the force transfer, bond-stress, bond shear transmission length, and strains were studied. Comparisons between the bond strength of the studied specimens and ordinary types column specimens from 13 previous studies showed a superior bond capacity for the new type specimens. Five related models of bond capacity were discussed, and the utility of the models was put forward. A simplified load-slip model was proposed and verified. The most feasible model and the simplified model were used in the parametric study. The results showed that the material strengths and geometric configurations parameters affect the bond strength capacity. The confinement and SCs have effects on the bond and failure mode. The natural bond-stress combined with SCs produced smaller bond strength than that from both natural bonds and using higher ρsv. Recommendations for future works are developed.

Effect of Spent Garnet Waste as Partial Fine Aggregate Replacement on Properties of High Strength Lightweight Aggregate Concrete

As time goes on, the usage of natural resources for concrete production affects the environment. Both the quarrying activities for granite aggregate harvesting and sand mining destroys the environment. At the same time, industrial by-products namely palm oil clinker (POC) and spent garnet waste which thrown as waste, also cause pollution. The inclusion of spent garnet waste as fine aggregate replacement in POC lightweight aggregate concrete production would reduce the consumption of river sand. This research investigates the effect of using spent garnet waste as a fine aggregate replacement on workability, dry density, and compressive strength of POC lightweight aggregate concrete. Five concrete mixes were prepared by varying the percentage of spent garnet waste as a fine aggregate replacement up to 40% by the weight of fine aggregate. All concrete specimens underwent water curing until the testing age of 7 and 28 days. The specimens were tested to determine dry density and compressive strength. Overall, the use of spent garnet as partial fine aggregate replacement influences the concrete properties. Inclusion of 20% spent garnet in concrete resulted in formation of semi-lightweight concrete with density of 2240 kg/m3. On top of that, the concrete with spent garnet exhibit higher compressive strength of about 60MPa which is about 14% higher than control specimen. Conclusively, the utilization of spent garnet as a partial fine aggregate replacement would save river sand consumption and reduce the dumping of spent garnet.

Probabilistic flexural fatigue strength of ultra-lightweight cement concrete and high strength lightweight aggregate concrete

Recently, more attention has been paid to the development of lightweight aggregate concrete due to its many advantages, such as low density, good thermal insulation, and fire resistance. The fatigue performance of ultra-lightweight cement composite (ULCC) and lightweight aggregate concrete (LWAC) with comparable compressive and flexural strength was investigated and compared in this paper. The data of three-point flexural fatigue loading experiments were collected from the literature for 108 specimens sized as 100 mm × 76 mm × 406 mm. The least-squares regression (LR) and the orthogonal regression (OR) methods were adopted and compared to fit the experimental coefficients of the Wöhler equations. Two- and three-parameter Weibull distribution models were used and compared when evaluating the probabilistic fatigue life of ULCC and LWAC at given stress levels. Analysis results show that the coefficients of the Wohler equations fitted by LR and OR methods in this study are similar. For stress levels in the middle ranges, namely, approximate 0.65–0.8, the differences of the S-N curves by two and three-parameter models are slight. When stress levels are larger than 0.8 or smaller than 0.65, significant differences exist between curves fitted by the two models. The nonlinear curves obtained from the three-parameter model are deemed more consistent with the actual situation than the linear curves by the two-parameter model.

Численный анализ поведения изгибаемых железобетонных балок, изготовленных из легкого высокопрочного бетона, с разным коэффициентом армирования

Lightweight high-strength concrete structures are currently spreading, primarily in civil engineering and bridge construction. High-strength lightweight aggregate concrete has advantages over heavyweight concrete when used in structures that must have high strength and buoyancy due to lower density and high enough strength. In this regard, it seems appropriate to use lightweight high-strength concrete in hydraulic engineering construction in offshore oil platforms and dry dock gate. In the presented work, computational studies of the stress-strain state of reinforced concrete beam structures made of light high-strength concrete have been carried out. To model the behavior of reinforced concrete beams made of lightweight high-strength concrete, spatial finite-element models have been developed. Researches were performed in the software «ANSYS». The developed models are verified by data of full-scale tests of beams with two reinforcement coefficients: 0.036 and 0.015. The performed studies allowed making a conclusion about the difference in behavior and destruction of beams at two reinforcement coefficients.

Properties of high-strength lightweight concrete using manufactured aggregate

The physical and mechanical properties of high-strength lightweight concrete were investigated considering various parameters including mixture design proportions, dosages and types of superplasticiser and silica fume and cement content aiming at a design strength of 45 MPa. The experimental results of density, tensile strength, modulus of elasticity and efficiency factor (ratio of compressive strength to density) were compared with empirical equations previously proposed in the literature. In earlier studies, using expanded clay coarse aggregate of maximum size 25 mm, the lightweight concrete presented a maximum strength of 30 MPa and an efficiency factor of 18·9 MPa.dm3/kg. By reducing the maximum size to 9·5 mm, a higher compressive strength of approximately 46·9 MPa and an efficiency factor of 28·3 MPa.dm3/kg were obtained. However, using expanded shale coarse aggregate yielded higher values of compressive strength and efficiency factor at 64·3 MPa and 36·3 MPa.dm3/kg, respectively. The replacement of coarse expanded clay aggregate with expanded shale resulted in a high-strength lightweight aggregate concrete with the best properties in this study: fc28 = 64·3 MPa, a density of 1·77 kg/dm3 and an efficiency factor of 36·3 MPa.dm3/kg.

Experimental Study of High‐Strength Steel Fiber Lightweight Aggregate Concrete on Mechanical Properties and Toughness Index

In this paper, three different kinds of steel fibers, being micro (M), end‐hooked (H), and corrugated (C), commonly used in engineering applications, are added to high‐strength lightweight aggregate concrete (HLAC) to study the effects of steel fiber and volume content ratio of fiber on the compressive, splitting tensile, and flexural strength of HLAC. The range of steel fiber volume content fraction studied is 0.5% to 2.0%. The research shows that different types of steel fiber have different effects on the mechanical properties and toughness of HLAC. M steel fibers have the best reinforcing performance on the mechanical properties. The study also shows that the toughness of M steel fibers is the best with the same fiber content. The toughening effect of H and C steel fibers can only reach 2/3 and 1/2 of M steel fibers, respectively. At the end of this paper, the unified strength formula and toughness index of these three kinds of high‐strength steel fiber lightweight aggregate concrete (HSLAC) with different fiber contents are given to provide a reference for engineering practice and design.

Preparation of high strength lightweight aggregate concrete with the vibration mixing process

This paper employs a novel mixing process with vibration to prepare the High Strength Lightweight Aggregate Concrete (HSLWAC), which compared with the non-vibration mixing process at four groups of different mixing proportion. The macroscopic performance was measured by slump test, dry density test and compressive strength test, and the microscopic characteristics were analyzed by digital image processing (DIP), thermal gravity analysis (TGA) and scanning electron microscopy (SEM). The results indicated the workability and mechanical properties of HSLWAC were both significantly improved by using the vibration mixing process. Moreover, the distribution conditions of lightweight aggregates (LWA) tended to be more uniform relative to that under the non-vibration mixing process. Furthermore, the hydration degree of cement paste in the 28 days was improved by 2.70% and 2.07% at the w/b ratio of 0.28 and 0.40, respectively, due to the favorable dispersing behavior of cementitious particles. In addition, an impregnation effect appeared on the ITZ was only observed by the vibration process, indicating the obvious enhancement of bond strength between LWA and cement matrix. It is expected that the vibration mixing process could be a more efficient way to prepare HSLWAC, which could be widely used in fabricated production as a promising mixing process.

Efficiency Development of Light Weight High Strength Concrete by using Carbon Fibers.

This study aims to progress brittleness of the high strength lightweight aggregate concrete (HSLWAC) by using Porcelinite stone as light weight aggregates and silica fume with water cement ratio 0.28 to give 41.34 MPa compressive strength at 28-days and reinforced with carbon fibers. Fifteen mixtures using in this work with three various lengths of (5mm, 10mm, and 20mm), five mixes for every length with volume fractions (0.25%, 0.5%, 1.0%, 1.5%, and 2%) of carbon fibers. The slump test, compression strength, flexural strength, splitting tensile strength, and modulus of elasticity were investigated to determine the mechanical properties of (HSLWAC). The density of reference (HSLWAC) that was get through the experimental work was (1835 Kg/m3) at (28) days. The results shown that at general, the brittleness of (HSLWAC) improved with increased the content and length of carbon fibers, The optimum properties was for mix (L5) of 20mm length and 2% of carbon fibers of 45.44 MPa, 3.21MPa ,and 6.97MPa for compression strength, flexural strength, splitting tensile strength respectively.

Flexural Behavior of Steel Fiber–Reinforced Lightweight Aggregate Concrete Beams Reinforced with Glass Fiber–Reinforced Polymer Bars

AbstractNine beams reinforced with glass fiber-reinforced polymer (GFRP) bars and one reinforced with steel rebars fabricated using high-strength lightweight aggregate concrete (HSLC) were tested u...

Flexural fatigue behavior of ultra-lightweight cement composite and high strength lightweight aggregate concrete

This paper investigated the fatigue performance of ultra-lightweight cement composite (ULCC) and lightweight aggregate concrete (LWAC) subjected to flexural load. The ULCC having mean density of 1450 kg/m3 contained cenosphere as micro aggregates and 0.9% volume of polyvinyl alcohol (PVA) fibers. The average 28-days cylinder compressive strengths of the ULCC and LWAC were 62 MPa and 63 MPa, respectively. 108 specimens were tested to measure the flexural fatigue strength under third-point loading. All the specimens were sized as 100 × 76 × 406 mm with an effective span of 300 mm. Using the experimental results, S-N curves were plotted and regression analysis was conducted to propose the equations (called Wöhler equations) for predicting the flexural fatigue strength of ULCC and LWAC. Also, the probabilistic distributions of fatigue life of ULCC and LWAC at a given stress level were modeled using the two-parameter Weibull distribution. The distribution parameters were obtained using three different methods. Design fatigue lives were obtained at different stress levels for ULCC and LWAC corresponding to different failure probabilities. The S-N relationship incorporating the failure probability is found more conservative than that found by Wöhler fatigue equation. The flexural fatigue performance of ULCC is better than that of LWAC, both of having similar strength.

Structural Behavior of Durable Composite Sandwich Panels with High Performance Expanded Polystyrene Concrete

Sandwich panels comprising prefabricated ultra-high performance concrete (UHPC) composites can be used as eco-friendly and multi-functional structural elements. To improve the structural and thermal performance of composite sandwich panels, combinations of UHPC and expanded polystyrene (EPS) beads were investigated. High-performance expanded polystyrene concrete (HPEPC) was tested with various EPS bulk ratios to determine the suitability of the mechanical properties for use as a high-strength lightweight aggregate concrete. As a core material in composite sandwich panels, the mechanical properties of HPEPC were compared with those of EPS mortar. The compressive strength of HPEPC is approximately eight times greater than that of EPS mortar, and the thermal conductivity of approximately a quarter that of EPS mortar. The structural behavior of composite sandwich panels was empirically analyzed using different combinations of cores, face sheets, and adhesive materials. In the flatwise and edgewise compression tests, sandwich panels with HPEPC cores had high peak strengths, irrespective of the type of face sheets, as opposed to the specimens with EPS mortar cores. In the four-point bending tests, the sandwich panels with HPEPC cores, or reinforced UHPC face sheets combined with adhesive mortar, exhibited higher peak strengths than the other specimens, and failed in a stable manner, without delamination.

Manufacturing of high-strength lightweight aggregate concrete using blended coarse lightweight aggregates

Structural lightweight concrete plays an important role in the construction industry, especially for the high-rise buildings. It can only be produced using lightweight aggregates. Oil-palm-boiler clinker (OPBC) is a solid waste from the oil palm industry and could be used as lightweight aggregate in concrete mixture. However, the density of this lightweight aggregate is more than the density of the other types of natural and artificial lightweight aggregate. Therefore, the density of concrete was made of this lightweight aggregate is relatively high and is in the range of semi-lightweight concrete. In the current study, OPBC was partially substituted with a lighter lightweight aggregate namely oil palm shell (OPS) in a OPBC semi-lightweight concrete with high strength to further reduce the density of the concrete. To this end, OPBC was replaced by OPS with 0%, 20%, 40% and 60% by volume. Test results show that contribution of OPS in OPBC concrete reduces the density, while all the mechanical properties were also reduced. This occurs due to smooth surface texture of OPC and its lower density compared to OPBC. It was, however, found that OPBC semi-lightweight concrete containing more than 20% OPS turns to be structural lightweight concrete with high strength. Based on the mechanical properties and water absorption test results it is recommended that the optimum substitution of OPBC with OPS stays between 20 to 40%.