Rheological Properties Of Materials Research Articles

Robust prediction of workability properties for 3D printing with steel slag aggregate using bayesian regularization and evolution algorithm

This study addresses the growing interest in utilizing steel slag as a sustainable alternative to river sand in additive manufacturing of concrete, driven by the increasing scarcity of natural resources. The rheological properties of fresh material significantly impact the quality of 3D-printed filament, necessitating suitable workability for printability. The research focuses on evaluating the influence of steel slag aggregate and key admixtures, such as silica fume and superplasticizer, on the workability properties of fresh concrete. Through an extensive series of 90 slump tests, optimal combinations ensuring the desired workability for 3D printing applications were identified. To enhance the manufacturing of fresh concrete and develop user-friendly tools, a novel soft computing approach is introduced—Adaptive Elitist Differential Evolution coupled with Bayesian Regularization Artificial Neural Network (aeDE-BRANN). This advanced model considers five critical input parameters: silica fume to Portland cement ratio, steel slag to cement ratio, water to cement ratio, cement content, and superplasticizer dosage. The model outputs crucial workability metrics, including slump flow and slump. In a comprehensive comparative study, the aeDE-BRANN framework demonstrates superior performance in terms of both simplicity and efficiency when compared to other forecasting models. Feature analysis techniques, including Shapley values from game theory and partial dependence plots, provide valuable insights into the intricate relationships between input variables and workability properties. The findings underscore the water to cement ratio as the most influential factor on workability, followed by silica fume to Portland cement ratio and steel slag to cement ratio. This study contributes a reliable tool for predicting workability properties, aiding in the selection of suitable steel slag aggregate and admixtures. Ultimately, it facilitates the sustainable and innovative evolution of 3D concrete printing practices.

Impact of Rheology-Based Optimum Parameters on Enhancing the Mechanical Properties and Fatigue of Additively Manufactured Acrylonitrile-Butadiene-Styrene/Graphene Nanoplatelet Composites.

This study investigates the interaction between static and fatigue strength and the rheological properties of acrylonitrile-butadiene-styrene (ABS) polymer reinforced with graphene nanoplatelets (GNPs) in both filament and 3D-printed forms. Specifically focusing on the effects of 1.0 wt.% GNPs, the study examines their influence on static/fatigue responses. The rheological behaviour of pure ABS polymer and ABS/GNPs nanocomposite samples, fabricated through material extrusion, is evaluated. The results indicated that the addition of 1.0 wt.% GNPs to the ABS matrix improved the elastic modulus of the nanocomposite filaments by up to about 34%, while reducing their ductility by approximately 60%. Observations revealed that the static and fatigue responses of the composite filament materials and 3D-printed parts were not solely attributed to differences in mechanical properties, but were also influenced by extrusion-related process parameters. The shark-skin effect, directly related to the material's rheological properties, had a major impact on static strength and fatigue life. The proposed method involved adjusting the temperature of the heating zones of the extruder during filament production to enhance the static response of the filament and using a higher nozzle temperature (270 °C) to improve the fatigue life of the 3D-printed samples. The findings reveal that the proposed parameter optimisation led to filaments with minimised shark-skin effects, resulting in an improvement in ultimate tensile strength compared to pure ABS. Moreover, the 3D-printed samples produced with a higher nozzle temperature exhibited increased fatigue lives compared to those manufactured under identical conditions as pure ABS.

Reducing plug flow effect on measured rheological results of cement-based materials: Image analysis and numerical iteration approach

The rheological properties of cement-based materials (CBM) significantly influence their workability and application in construction. Despite the common use of coaxial cylinder rheometers for measuring these properties, challenges arise, particularly at low shear rates due to plug flow within the tested samples. This study aims to investigate the impact of plug flow on rheological property measurements of CBM and proposes strategies to enhance measurement accuracy. An image analysis method and a novel numerical iteration algorithm were proposed in this study to address plug flow effects. Three series fresh cement paste with different fluidities were prepared to conduct the rheological tests. Through the image analysis method, actual shear radii at different rotor speeds were measured. The corresponding rheological parameters were determined and compared using the complete shear assumption, the image analysis method, and numerical iteration algorithm, respectively. The results indicated the great influence of plug flow on rheological results, especially at low shear rates and low fluidities, highlighting the need for its consideration in rheological parameters calculations. Moreover, the proposed numerical iteration algorithm was verified to calculate the incomplete shear state of CBM and improve the measurement accuracy of rheological parameters. The extensions and limitations of the numerical iteration algorithm in its application were discussed further.

The Application of 3D Printing Formwork Technology in Concrete Building Materials

Concrete 3D printing technology is a prime example of contemporary digital manufacturing, showcasing its efficiency and automation in the realm of construction. Compared to traditional construction methods, the characteristics of labor-saving and formwork-free in 3D printing technology have brought changes to the construction personnel structure and forming process. Enhancing the flexibility of concrete materials and 3D printing technology are two major areas of concentration, along with promoting the wider application of 3D printing in the construction industry. An extensive review of the advancements in concrete 3D printing technology is given in this paper. The mechanical, printable, buildable, and rheological properties of concrete materials that are suitable for 3D printing are also discussed. The study also shows how 3D printing formwork technology is frequently used in decorative elements and atypically shaped projects. The goal is to offer informative analysis and practical tools for further research and advancements in 3D printed concrete technology. The study's overall findings emphasize how important it is to improve 3D printing technology's compatibility with concrete materials. By tackling essential performance criteria and exploring creative uses, we can unlock the complete potential of concrete 3D printing, which will result in notable progress within the construction sector.

A reexamination of the Cox–Merz rule through the lens of recovery rheology

Empirical rules play a crucial role in industrial and experimental settings for efficiently determining the rheological properties of materials, thereby saving both time and resources. An example is the Cox–Merz rule, which equates the steady-shear viscosity with the magnitude of the complex viscosity obtained in oscillatory tests. This empirical rule provides access to the steady-shear viscosity that is useful for processing conditions without the instabilities associated with experiments at high shear rates. However, the Cox–Merz rule is empirical and has been shown to work in some cases and fail in others. The underlying connection between the different material functions remains phenomenological and the lack of a comprehensive understanding of the rheological physics allows for ambiguity to persist in the interpretation of material responses. In this work, we revisit the Cox–Merz rule using recovery rheology, which decomposes the strain into recoverable and unrecoverable components. When viewed through the lens of recovery rheology, it is clearly seen that the steady-shear viscosity comes from purely unrecoverable acquisition of strain, while the complex viscosity is defined in terms of contributions from both recoverable and unrecoverable components. With recovery tests in mind, we elucidate why the Cox–Merz rule works only in a limited set of conditions and present an approach that could allow for universal comparisons to be made. This work further highlights the significance of recovery rheology by showing how it is possible to extend beyond phenomenological approaches through clear rheophysical metrics obtained by decomposing the material response into recoverable and unrecoverable components.

Development, Prospect and Challenge for Additive Manufacturing of Polymer Materials

As a manufacturing technology that fabricates three-dimensional objects by stacking materials layer by layer, additive manufacturing can be divided into laser fused deposition, electron beam fused deposition, inkjet printing and so on based on different additive manufacturing processes. In recent years, remarkable progress has been made in the additive manufacture of polymer materials. Firstly, the additive manufacturing equipment and process parameters suitable for polymer materials have been successfully developed, which realized the accurate manufacturing of complex structures. Secondly, by optimizing the formula and post-treatment of polymer materials, the performance and durability of additive products are improved. In addition, the researchers also explored the application potential of additive manufacturing of polymer materials in medical, aerospace and other fields. However, the additive manufacturing of polymer materials still faces some challenges. One of them is that the rheological properties of polymer materials have a great impact on the progress of additive manufacturing, which needs further research and improvement. Meanwhile, the heat and stress generated in additive manufacturing may lead to the deformation and degradation of polymer materials, which requires effective thermal management. Finally, compared with the traditional cutting process, the additive manufacturing cost of polymer materials is still high, so it is necessary to reduce the cost and promote production efficiency. In a word, additive manufacturing of polymer materials has broad prospects and application potential, but further research and improvement are still needed to overcome related challenges.

Investigation of rheological properties of extruded composites based on UHMWPE

The influence of the CO-4 stabilizer on the rheological properties of polymer composite materials based on UHMWPE has been studied. It has been shown that the addition of a CO-4 stabilizer to polymer matrices significantly affects the rheological properties of materials and their extrudability. There is a change in the conformations of macromolecular chains, the absence of dependence of the viscous component on the relaxation process of the dispersed system, an increase in the complex viscosity, which led to a deterioration in the processability of the material. Based on the Han curves, it is shown that the addition of a CO-4 stabilizer leads to a deterioration in the miscibility of mixtures, i.e., the phase separation of the components of the obtained samples increases.

Application of ultrasonic waves to evaluate the rheological properties of non-Newtonian slurries: a preliminary study

An ultrasonic-wave system was developed to measure the rheological properties of non-Newtonian materials based on their responses to shear and pressure waves. This system was composed of a commercial shear wave transducer and various homemade devices, including a signal generator, a signal conditioner, and a transmission/receiving switch. The shear wave reflections at the interface between the delay line and the unknown test materials can be interpreted by the signals measured with calibration materials (e.g. air, water, olive oil and honey) that have well-known rheological properties. If the Voigt viscoelastic model is used to describe the dynamic behaviour of these test materials, the interpreted data can be used to determine the acoustic impedances, and thus solve for their shear moduli (G), kinematic viscosities (ν) and bulk densities (ρ). After the calibration procedures, the proposed system was used to test a consolidating kaolinite slurry with zero salinity and an initial suspended sediment concentration of 420 g l–1. The measurements showed that the shear modulus G is developed until consolidation for approximately 100 h. Afterward, the G gradually approached a value on the order of 500 N m–2 after approximately 200 h. This corresponded to an initial viscosity of approximately 7 × 10−5 m2 s–1, which decreased slowly over time to approximately 4 × 10−6 m2 s–1 after 300 h. With minor modification to capture pressure waves from the shear wave transducer, the bulk density can also be measured. The integrated system offers a non-invasive and efficient method for characterizing non-Newtonian fluids, providing valuable insights into their rheological properties, which are crucial for a wide range of industrial and scientific applications.

Rheology and yield stress evolution of highly flowable cementitious grouting materials: Mechanisms and modeling

To study the rheological properties of grouting materials, the effects of sand-binder ratio, water-binder ratio, and rest time on the rheological model and parameters were studied through rheological tests. Through the cryo-scanning electron microscopy test to observe the structural build-up process of microstructures with rest time, the particle size test to measure the size distribution variation of flocculated structures over rest time, and the low-field nuclear magnetic resonance test to measure the change of water content in the slurry, the evolution mechanism of yield stress was studied. The results showed that the rheological model was consistent with Herschel–Bulkley model (H–B model). The yield stress increased with time. The growth of network flocculated structures and the decrease in the lubrication effect of water caused an increase in the aggregate particles–cement paste interaction stress. Therefore, the yield stress of the grouting materials increased over time. Considering the combined influences of the flocculation effect, hydration reaction, and the aggregate particles–cement paste interaction, a new evolution model was proposed to better describe the evolution law of yield stress with time. The results could provide a basis for the study on flow diffusion of grouting materials and an in-depth understanding of the time-dependent rheological properties of cement-based materials containing aggregate particles.

Fully angularly resolved 3D microrheology with optical tweezers

Microrheology with optical tweezers (MOT) is an all-optical technique that allows the user to investigate a materials’ viscoelastic properties at microscopic scales, and is particularly useful for those materials that feature complex microstructures, such as biological samples. MOT is increasingly being employed alongside 3D imaging systems and particle tracking methods to generate maps showing not only how properties may vary between different points in a sample but also how at a single point the viscoelastic properties may vary with direction. However, due to the diffraction limited shape of focussed beams, optical traps are inherently anisotropic in 3D. This can result in a significant overestimation of the fluids’ viscosity in certain directions. As such, the rheological properties can only be accurately probed along directions parallel or perpendicular to the axis of trap beam propagation. In this work, a new analytical method is demonstrated to overcome this potential artefact. This is achieved by performing principal component analysis on 3D MOT data to characterise the trap, and then identify the frequency range over which trap anisotropy influences the data. This approach is initially applied to simulated data for a Newtonian fluid where the trap anisotropy induced maximum error in viscosity is reduced from ~ 150% to less than 6%. The effectiveness of the method is corroborated by experimental MOT measurements performed with water and gelatine solutions, thus confirming that the microrheology of a fluid can be extracted reliably across a wide frequency range and in any arbitrary direction. This work opens the door to fully spatially and angularly resolved 3D mapping of the rheological properties of soft materials over a broad frequency range.

3D printed sweets made with peanut chenna and milk: A new frontier in food technology

AbstractThe recent development of three‐dimensional (3D) food printing technology is having an important impact on the food processing sector. This cutting‐edge method permits the manufacturing of foods with outstanding customization in terms of both look and nutritional profile. Several methods have been applied to demonstrate how 3D printing can be adopted in the food processing sector. These methods include selective laser sintering, hot‐melt extrusion, and inkjet printing. In contrast, high‐temperature techniques are not appropriate for constructing 3D representations of nutrients that are sensitive to changes in temperature. Cold extrusion is an effective alternative approach for 3D printing; however, its successful implementation requires the inclusion of rheology substitutes and the careful standardization of different elements involved in the process. In order to overcome this constraint, we utilized the technique of direct ink writing for 3D printing of the product by cold‐extrusion. This was achieved by using a combination for the different material formulations. This research provides confirmation on the feasibility of using 3D printing technology to print peanut based chenna, with the incorporation of skim milk (SM) powder, while maintaining a minimal material formulation. The flow properties of printing material compositions can be accurately explained with the R2 > 0.996 Power‐law and Herschel–Bulkley model. The flow behavior index, denoted as n, (n < 1), suggesting that the fluid exhibits shear thinning properties. The value of the loss modulus (G″) for material formulation was significantly lower than that of the storage modulus (G′). It was found that the storage modulus and the viscous modulus both emerged higher with increasing angular frequency. The formulation of the material, with its higher storage modulus indicating better durability, enables printing of a broad spectrum of food items. The primary objective of this study was to investigate the enhancement of printability in food compositions through the utilization of peanut‐based chenna. In order to achieve consistent and accurate results at different ratios (1:1, 2:1, and 3:1, w/w), a comprehensive evaluation was conducted on several printing parameters. These parameters included printing formulations, height of the nozzle, diameter, or size of nozzle, printing rate of speed, extrusion motor speed, and rate of extrusion. The extrusion printing parameters were adjusted to achieve optimal printing conditions for a 2:1 composition of SM powder and peanut‐based chenna. These parameters included the height of nozzle (0.314 mm), size of nozzle (0.4 mm), printing speed (30 mm/s), extrusion rate (5.21 mm3/s), extrusion motor speed (240 rpm), and extruder pressure (5 bar).Practical applicationsThe emergence of food printing is a game‐changer for the culinary world. 3D food printing has expanded the creative options available to chefs, bakers, and entrepreneurs in the food industry by making it possible to print unique and complex designs directly onto edible substrates. In this research, we looked into the material compositions, time standardization, extrusion rate, printing speed, and rheological properties of a food formulations. The present research uses a 3D food printer to explore the unexplored possibilities of a combination of peanut‐based chenna and SM for the purpose of product development.

Искусственный интеллект в материаловедении и современных технологиях бетонных материалов: анализ возможностей и перспектив

An analysis of current trends and opportunities for the application of artificial intelligence (AI) in materials science and concrete technology, including 3D printing in construction, is presented. The key role of AI in predicting material properties, developing new materials, and quality control is highlighted. By analyzing large volumes of data collected from numerous studies, AI can suggest optimal parameters to achieve desired material properties, thereby reducing costs and increasing production efficiency. Existing rheological models, such as the Bingham-Shvedov model or the Herschel-Bulkley model, describe material behavior based on specific equations and parameters. These models can be useful in predicting concrete properties, especially when data on its component composition is available. However, these models may be limited in their predictive accuracy, particularly for non-standard or novel materials. It has been found that machine learning and neural networks have the potential to provide accurate predictions of rheological and physico-mechanical properties of concrete materials, considering multiple parameters that influence material characteristics, including chemical and mineralogical composition, as well as structural features. The combination of experimental data and AI can successfully optimize compositions and properties during production, reducing costs and research/testing time, and opening new opportunities for researchers and engineers in the field of materials science. Machine learning algorithms such as XGBoost, LightGBM, Catboost, and NGBoost demonstrate high predictive accuracy and have become powerful tools in the design of concrete compositions and innovative technologies. The analysis of Shapley additive explanations (SHAP) allows us to understand which parameters of a concrete mixture have the greatest influence on its characteristics.

New biopolymers as viscosity-modifying admixtures to improve the rheological properties of cement-based materials

The performance of various new biopolymers as viscosity-modifying admixtures (VMAs), including tragacanth, almond, and locust bean gums and giant kelp extract, in addition to two commercial biopolymer-VMAs, welan and guar gums in cement-based materials was evaluated. The effect of the preparation/addition method, type, and dosage of the investigated biopolymers on rheology, hydration kinetics, stability, and compressive strength of various cement paste mixtures was evaluated. The pre-dispersion and pre-dispersion/pre-hydration techniques showed greater influence on the rheology of the investigated mixtures compared to dry addition. Moreover, the investigated biopolymers led to a shear-thinning response with higher viscoplastic properties than the reference. The structural build-up of the mixtures was mainly influenced by the type and dosage of the biopolymers, observing higher performances in mixtures containing guar gum, giant kelp extract, and welan gum. The use of the investigated biopolymers enhanced the stability of the paste mixtures, while negatively influenced the early-age strength development.

Evaluation of the effect of rubber waste particles on the rheological and mechanical properties of cementitious materials for 3D printing

The use of 3D printing for cementitious materials is an increasingly viable option technically, economically, and environmentally for civil construction, generating a lower amount of waste. This work aims to evaluate the technical feasibility of using rubber as a fine aggregate in 3D printing mortars and its impact on its rheological and mechanical properties. Tests of compressive and flexural strength, flow-table, rheology and squeeze-flow were conducted to evaluate their fresh and hardened state properties. The total substitution of natural sand for rubber increased the rheological properties of dynamic yield stress (318–479.3 Pa), static yield stress (1604.1–1760.1 Pa) and plastic viscosity (4.15 Pa.s to 5.03 Pa.s). Lower compressive (19.9 MPa) and flexural (5.6 MPa) strengths were obtained for the mortar using rubber waste as aggregate. Also, the replacement of sand with rubber enhanced the anti-thixotropic behavior of 3D printing mortars.

Modeling of Contact Interaction of Two-Layer Bodies Taking into Account Adhesion and Rheological Properties of Coating or Substrate Materials

Modeling of Contact Interaction of Two-Layer Bodies Taking into Account Adhesion and Rheological Properties of Coating or Substrate Materials

Implementation and validation of a bonded particle model to predict rheological properties of viscoelastic materials

This work focuses on implementing a particle-based method able to characterize viscoelastic materials whose rheological properties, such as storage modulus G’ and loss modulus G”, are known. It is based on the Bonded Particle Model, with the elastic constitutive relation here substituted with a viscoelastic one to capture time-scale effects. The Burgers model, vastly used in literature to model viscoelastic systems, is discretized and implemented. The test case used for calibration comprises of a cubic lattice, sheared with a periodic motion, to mimic the effect of a shear rheometer. After appropriate filtering of the stress response, the rheological properties are obtained, highlighting the effect of the lattice geometry, as well as the particle size, on the accuracy of the model. Moreover, the Burgers parameters are calibrated by analytically fitting the experimental dataset, showing the limitation of the Burgers model. The micro-contact parameters are obtained from the macro parameters through appropriate scaling. After completing a frequency sweep, the simulated G’ and G” show a relatively large error, around 25% for G’ for example. For this reason, a more robust model, namely the Generalized Maxwell Model, has been implemented. The calibration procedure is performed in the same fashion as for the Burgers model. Moreover, the tangential micro-contact parameters are scaled w.r.t. the normal ones. This scaling parameter, called α, is calibrated by minimizing the Root Mean Square Error between simulation and experimental data, giving errors below 10% in both G’ and G” for a large dataset. Additionally, a full ring plate-plate rheometer setup is simulated, and the simulation is compared with the given experimental dataset, again finding a good agreement.

Validation of a Mathematical-Based Model for the Rheological Characterization of Asphalt Mixtures

Asphalt mixtures are viscoelastic materials whose behavior is highly dependent on temperature and loading frequency. The influence of these factors is described through master curves constructed at a given reference temperature based on the principle of frequency-temperature superposition. These curves are used as inputs in asphalt pavement design procedures based on mechanistic principles and related to their in-service pavement performance. This paper proposes the application of the Kramers-Kronig (K-K) relations to characterize the rheological properties of asphalt materials using a mathematical approach. Due to the complexity of the integration of the K-K relations, an approximate solution of the K–K relations was used to develop a Mathematical-Based Model to predict the master curves for the Dynamic Modulus |E*| and the Phase Angle f. This model was validated using the experimental results of two different asphalt mixtures with different characteristics. The results indicate that the model is accurate, and could be an effective approach to mathematically predict the master curves of the asphalt mixture viscoelastic properties in a wide range of temperatures and frequencies.

Geometric Conformability of 3D Concrete Printing Mixtures from a Rheological Perspective

The effectiveness of 3D concrete printing (3DCP) relies on understanding the rheological properties of cementitious materials and their time-dependent evolution. These materials exhibit shear-thinning viscosity, an elastic region, and both static and dynamic yield stress, which are challenging to balance in 3DCP. Layer deformation can be caused by factors such as self-weight, the weight of subsequently deposited layers, and the stress induced by the nozzle pressing. Starting at the level of a single filament, the final geometrical conformity of a 3D-printed object is the sum of individual filament conformities. Hence, the control of layer deformation during the printing process is critical. The failure of 3D-printed objects can occur due to two primary mechanisms: material failure, which occurs when the material’s strength is exceeded, resulting in fracture or uncontrolled deformation; and stability failure, where the object cannot retain equilibrium of forces. These mechanisms often interact; extensive deformations resulting from material failure can lead to stability loss, or conversely, stability loss generates local excessive stresses leading to material failure. The governing mechanism depends on various factors, including material and process characteristics, as well as the transient nature of material properties, print strategy, and object design. With this in mind, this research aimed to broaden the understanding of the connection between rheological material properties—primarily yield stress—and the geometric conformability of printed objects. Experimental tests were conducted on pastes using a rheometer, and correlated mortars, allowing for the evaluation of realistic extrusion properties.

Combined effect of heating temperature and content of pectin on the textural properties, rheology, and 3D printability of potato starch gel

Three-dimensional (3D) printing is one of the emerging techniques which fabricates customized foods with desired sensory characteristics. Rheological properties of 3D printing materials are vitally important in printability which govern the flowability and structural stability. Due to its unique gel-forming characteristics, potato starch has been extensively used in myriad food applications, such as 3D printing. However, little attention has been paid to the combined effect of heating temperature and pectin addition on the properties of potato starch gels. Thus, this study investigated the impact of different pectin contents (1, 1.5, and 2 %) on printability and the rheological and textural properties of potato starch gels heated at different temperatures (70, 80, and 90 °C). The gel heating temperature governs pectin-driven modifications in potato starch gels. Pectin addition increased the 3D printability, viscosity, storage modulus, hardness, gumminess, and springiness of starch gel at higher temperatures (80 °C and 90 °C). In contrast, at lower temperatures (70 °C), pectin addition decreased printability, viscosity, storage modulus, hardness, gumminess, and springiness. Therefore, the gel heating temperature influences the impact of pectin on printability, rheology, and textural properties. Accordingly, the combined effects of pectin and heating temperature should be considered in pectin-based 3D food-printing ink formulations.

Influence of nano alumina reinforced superabsorbent polymer on mechanical, durability, microstructural and rheological properties of cementitious materials

Superabsorbent polymers (SAPs) are widely used in concrete for their promising effect in internal curing and crack sealing. Nano materials are efficient in improving the permeability and porosity of concrete with their smaller size and larger surface area. In this research , polyacrylamide (PAM) as superabsorbent polymer (SAP) along with nano alumina (NA) is proposed for small percentage of replacement in cement and their effects on mortar concrete were studied for mechanical and microstructural properties under self-curing and wet curing conditions. This study investigates the combined influence of nano alumina and polyacrylamide superabsorbent polymer hydrogel on chemical durability of cement mortar with HCl, CaCl2, and Na2SO4 immersion for 180 days. The effectiveness of replacing cement by composite mixture of polyacrylamide superabsorbent polymer and nano alumina at 0.1%, 0.2%, 0.3%, 0.4% and 0.5%, by weight, was investigated. Nano alumina modified by SAP was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) studies. Results indicate that NA/SAP combination in concrete improves hydration of cement enhancing the mechanical properties in concrete and similar properties are obtained in self-curing conditions indicating that SAP is good internal curing agent in concrete and NA is useful in filling up micro pores in concrete enhancing their strength. Hence, a composite admixture is proposed in concrete through this work for low-shrinkage, compact and dense concrete for the application in practical engineering.