Performance Of Concrete Mixes Research Articles

Interlayer Bond Strength of 3D Printed Concrete Members with Ultra High Performance Concrete (UHPC) Mix

Interlayer Bond Strength of 3D Printed Concrete Members with Ultra High Performance Concrete (UHPC) Mix

DESIGN AND FABRICATION OF CIVIL 3D PRINTER

The advent of 3D printing technology has revolution- ized the construction industry, offering innovative so- lutions for rapid, cost-effective, and sustainable build- ing practices. This research paper presents a compre- hensive study on the manufacturing and fabrication of a 3D concrete printer tailored for large-scale construc- tion applications. The paper outlines the design princi- ples, mechanical and electrical systems, material con- siderations, and software integration necessary for the development of an efficient and reliable 3D concrete printer. Key components of the printer, including the frame, extrusion system, and control mechanisms, are meticulously designed to ensure precision, stability, and durability. Advanced materials such as high- performance concrete mixes are formulated to meet the unique requirements of 3D printing, balancing workability, strength, and setting time. The integration of sensors and automation technology facilitates real- time monitoring and control, enhancing the accuracy and consistency of the printed structures. The implementation phase involved extensive testing and validation, highlighting the printer’s capability to construct complex geometries and large-scale ele- ments with minimal human intervention. Results indi- cate significant improvements in construction speed, cost savings, and material efficiency compared to tra- ditional methods. The paper concludes with a discus- sion on potential applications, challenges, and future directions for 3D concrete printing technology in the construction industry.

Impact of Superplasticizers on the Performance of Low-Grade Limestone-Based Cement Mixes.

Low-grade limestone (LGL) is not used to produce cement clinker, but this leftover material in cement quarries increases the water demand when used as a filler in concrete production. In this study, the effect of six commercial superplasticizers on the performance of cement mixes containing 35% LGL and 2% gypsum was investigated. The optimal doses of these superplasticizers were found in a range of different water/binder (w/b) ratios by conducting several Marsh cone and mini-slump tests. The addition of a superplasticizer with a higher active solid content produced a maximum cement flow, regardless of the w/b ratios. The LGL-based mortar samples admixed with this superplasticizer obtained a maximum compressive strength of about 36 MPa at the end of 28 days. SEM and XRD results showed the formation of a new calcium-rich mineral in their microstructure. These findings highlight the impact of the type and properties of superplasticizers on the performance of concrete mixes containing LGL as a supplementary cementitious material.

Study Of High Performance Concrete Using Local Materials (Fly Ash Of Pltu Labuhan Angin, Mount Sinabung Volcanic Ash And Silica Sand) On The Mechanical Properties Of Concrete

Currently in Indonesia a lot of construction work and concrete is one that is widely used. In the development of concrete construction technology, especially in Indonesia, it is necessary to have concrete capable of carrying high loads using available materials. The development of high quality concrete has 3 levels, namely High Strength Concrete (HSC), High Performance Concrete (HPC) and Ultra High Performance Concrete (UHPC). Against the background of future needs, in this study experiments were carried out in a concrete laboratory to obtain high performance concrete mixes with local materials. At the experimental stage, testing of tools and materials, concrete mix, casting, slump test, manufacture of specimens, maintenance, checking of unit weight, compressive strength test, split tensile strength and modulus of elasticity was carried out. In that study there were 11 variations. Furthermore, the test results were analyzed by the data to draw conclusions. The results showed that the average compressive strength of concrete at 3 days of age was relatively high, namely 53.8 MPa which could be used for fast precision work. In variation 11 mixture (PCC Cement, Silica Fume, Sand Mesh 35-60, Silica Mesh 325, Water, Viscocrete Superplasticizer 8670 MN, Fly Ash 7% and Polypropylene Fiber 0.2%) tested for 28 days, the compressive strength reached 87.5 MPa, so it can be said as HPC concrete. In this study it was concluded that the use of local materials, Sinabung Volcanic Ash waste and fly ash can improve the quality of concrete and can also reduce environmental pollution.

Performance and life cycle of ultra-high performance concrete mixes containing oil refinery waste catalyst and steel fibre recovered from scrap tyre

An economic solution to recycle spent equilibrium catalyst (Ecat) disposed of by petrochemical manufacturers and steel fibre recovered from scrap tyre would be their use in the production of structural concrete. In this study, the performance and life cycle of ultra-high performance concrete (UHPC) mixes containing these waste materials was examined. They were made using a total binder content of 1160 kg/m3 and also contained fly ash and silica fume in addition to Ecat and cement. Their average compressive strength at the end of 28 days was found to be above 150 MPa. The replacement of cement with Ecat reduced the CO2 emission and material cost of recycled steel fibre (RSF) reinforced UHPC samples by 15% and 6%, but there is no significant change in their compressive, flexural and split tensile strengths at the end of 28 days. Only 2% of the elastic modulus of these samples increased as a result of the addition of Ecat by weight of the binder. Ecat, an aluminosilicate material, is generally classified as a pozzolanic material, but its addition together with fly ash and silica fume in the UHPC mixture did not affect the strength gain properties. Based on our experimental findings, the use of waste materials including Ecat and RSF in the preparation of precast UHPC elements for explosion and earthquake resistant structures is recommended.

Prediction of fire spalling behaviour of fibre-reinforced concrete

Fire spalling prediction of fibre-reinforced concrete containing polypropylene (PP) or steel fibre at elevated temperatures is challenging. It is difficult to use conventional methods, such as finite-element modelling and discrete-element modelling, to solve the problem, because of the complicate coupling mechanism of PP and steel fibres in concrete. To this end, two artificial neural network (ANN) models, one (ANN1) based on a concrete mix study and the other (ANN2) based on a compressive strength study, were introduced to assess the resistance of concrete to explosive spalling. Test data (321 and 318 items, respectively) gathered from the literature were utilised to train the proposed models. Twenty-four concrete mixes (96 groups), that is, seven plain concrete mixes, four high performance concrete mixes reinforced with PP fibre, three ultra-high-performance concrete (UHPC) mixes with reinforced PP fibre and ten UHPC mixes reinforced with PP and steel hybrid fibres were designed and tested to validate the accuracy of the models. The study demonstrates that ANN1 and ANN2 can achieve a predictive accuracy of 89.6% and 84.4% for the explosive spalling, respectively, indicating the feasibility of the proposed models for predicting explosive spalling threat of the hybrid fibre-reinforced concrete.

AI Mix Design of Fly Ash Admixed Concrete Based on Mechanical and Environmental Impact Considerations

It has become very important in the field of concrete technology to develop intelligent models to reduce overdependence on laboratory studies prior to concrete infrastructure designs. In order to achieve this, a database representing the global behavior and performance of concrete mixes is collected and prepared for use. In this research work, an extensive literature search was used to collect 112 concrete mixes corresponding to fly ash and binder ratios (FA/B), coarse aggregate and binder ratios (CAg/B), fine aggregate and binder ratios (FAg/B), 28-day concrete compressive strength (Fc28), and the environmental impact point (P) estimated as a life cycle assessment of greenhouse gas emissions from fly ash- and cement-based concrete. Statistical analysis, linear regression (LNR), and artificial intelligence (AI) studies were conducted on the collected database. The material binder ratios were deployed as input variables to predict Fc28 and P as the response variables. From the collected concrete mix data, it was observed that mixes with a higher cement content produce higher compressive strengths and a higher carbon footprint impact compared to mixes with a lower amount of FA. The results of the LNR and AI modeling showed that LNR performed lower than the AI techniques, with an R2(SSE) of 48.1% (26.5) for Fc and 91.2% (7.9) for P. But ANN, with performance indices of 95.5% (9.4) and 99.1% (2.6) for Fc and P, respectively, outclassed EPR with 90.3% (13.9) and 97.7% (4.2) performance indices for Fc and P, respectively. Taylor’s and variance diagrams were also used to study the behavior of the models for Fc28 and P compared to the measured values. The results show that the ANN and EPR models for Fc28 lie within the RMSE envelop of less than 0.5% and a standard deviation of between 15 MPa and 20 MPa, while the coefficient of determination sector lies between 95% and 99% except for LNR, which lies in the region of less than 80%. In the case of the P models, all the predicted models lie within the RMSE envelop of between 0.5% and 1.0%, a coefficient of determination sector of 95% and above, and a standard deviation between 2.0 and 3.0 points of impact. The variance between measured and modeled values shows that ANN has the best distribution, which agrees with the performance accuracy and fits. Lastly, the ANN learning ability was used to develop a mix design tool used to design sustainable concrete Fc28 based on environmental impact considerations. Doi: 10.28991/CEJ-SP2023-09-03 Full Text: PDF

Optimization of Different Properties of Ultra- High Performance Concrete Mixes for Strengthening Purposes

The current research’s purpose is to examine how Ultra-High Performance Fiber Concrete (UHPFC) holds up in terms of strength and durability for strengthening purposes. For this reason, the experimental and the theoretical studies in this research attempted to assess different fresh and hardened properties of a variety of ultra-high performance combinations. Steel fibers were utilized to differentiate all of the program's combinations at percentages of 0.25 %, 0.5 %, 0.75 %, 1%, and 1.25 % by volume. Mini flow slump, compressive and flexural strength, ultrasonic pulse velocity, water absorption, and porosity tests were all used to examine the performance of the strength and durability of the material. The findings of this study's trials showed that steel fibers increased the strength of UHPFC. The steel fiber ratio of 1% gave the maximum compressive strength, whereas 1.25 percent yielded the highest flexural strength. Because the fibers function as a bridge, preventing internal breaking, the tensile test results were improved as the proportion of steel fiber rises. Through the use of the multi-objective optimization approach, the optimal ratio of fibers was chosen at the end of the laboratory work since it has the best durability and strength characteristics. Statistical software (Minitab 2018) was used to find the optimal combination of UHPFC that meets all of the requirements. The theoretical selected optimum ratio of 0.77% of fibers obtained from the optimization was evaluated and validated experimentally. The optimized mix provided 90.28 MPa, 14.6 MPa, and 20.2 MPa for compressive, splitting tensile and flexural tests respectively with better durability performance compared to other mixes prepared in this investigation.

Development of Cement Concrete Using Granite Dust and Fly Ash as Partial Substitutes

In this scenario, we observe how the strength of the concrete changes when the standard cement is switched out for granite powder and fly ash as the fine aggregate. In this particular investigation, the researchers employed anything from zero to fifty percent fine aggregate and whatever quantity of cement they deemed appropriate. Concretes of grade M25 and M60 are used since there is a need to take into account either low and high strengths. At room temperature, compressive testing was carried out on cubes of fly ash-added concrete that had been aged 7, 14, 28, and 90 days respectively. After 14 and 28 days after being mixed, cylinders of fly ash-added concrete were split and evaluated for their tensile strength. During a cure period of 28 days submerged in water, the flexural strengths of the concrete beams were measured. We were able to evaluate the chemical solution resistance of concrete made with fly ash and quarry dust by curing samples of concrete in a variety of chemical solutions and then determining the amount of strength and weight that was lost as a result. The high performance concrete mix that was created was made using the M60 grade of concrete. The major focus of this investigation is on the characteristics and performance of concrete in which the cement and fine aggregate have been partly substituted by large volume fly ash (HFA) and quarry dust (QD). The strength, stiffness, and residual strength of high-performance reinforced concrete beams were investigated and tested to see how they would perform under cyclic loading circumstances in terms of the deterioration of these properties. In this investigation, the researchers used a sophisticated chloride penetration technique to concrete that was produced using a combination of fly ash and quarry dust (RCPT). Last but not least, research was conducted on the compressive, split tensile, and flexural strengths, in addition to the chloride permeability, of concrete mixes that included varied amounts of fly ash and quarry dust. The findings demonstrate that reducing waste by recycling stone dust to pavement is a feasible alternative.

Ant lion algorithm for optimal design of high performance concrete mixes

This paper presents the development of Ant lion optimization (ALO) models for optimal mix proportioning of high volume fly ash concrete (HVFAC). The development of the model came through in two steps, firstly, a modest data pertaining to 450 mix designs that are generated either in laboratory or in field were garnered from the literature were statistically analyzed and 350 appropriate mix designs were retained and necessary constraints, upper and lower bounds, and rational ratios are elicited. In the second step ALO algorithm was applied to determine optimal proportions of fly ash, cement, and water corresponding to optimum compressive strength of concrete. Optimal mix proportions were computed for five ranges of compressive strengths using the objective function and constraints farmed in the first step. The optimized mix proportions for all the strength ranges are found to be highly acceptable and corroborate very well with experimental values with mean square error ranging between 2% and 4%, 7%−13%, and 10–12.5% in case of water, fly ash and cement respectively. Further, a systematic comparison of results obtained by the author in implementing other bio inspired algorithms namely, Ant colony optimization (ACO), Elitist genetic algorithm (EGA), Honey bee optimization (HBO), and Particle swarm optimization (PSO) is also made. It is found that the quantities of the ingredients are almost identical, however with marginal differences in the mean square error metric. It is found that GA was bit high in errors, followed by ALO, ACO, and HBO not appreciable though. However PSO showed low errors in the range 1.6%−3.2%, 5%−10%, and 5%−8.5% in the optimized quantities in respect of water, fly ash and cement respectively across five strength ranges.

Effect of different fiber combinations and optimisation of an ultra-high performance concrete (UHPC) mix applicable in structural elements

In this study, Ultra-High Performance Concrete (UHPC) mix was optimised to expand its use in large-scale applications. Using alternative curing methods instead of heat treatment, it was aimed that UHPC will meet the required strength and workability criteria and thus be presented applicable solutions for widespread use of UHPC in engineering applications. Therefore, effect of aggregate type, fiber content, curing method, compacting method, cement type, water/cement ratio and aggregate granulometry on mechanical properties of UHPC was investigated. Compressive strength, flexural tensile strength, splitting tensile strength, pull-out behaviour, modulus of elasticity and toughness values of the UHPC series were determined. Standard water curing (compared to wet hessian application) increased the compressive strength by 11.2% and the flexural tensile strength by 19%, while the inclusion of hybrid fibers (compared to the use of a single type of fiber) increased the compressive strength by 16.7% and the flexural tensile strength by 48%. Type of aggregate was found very effective on flexural tensile strength as well, and it provided additional ductility by increasing the matrix strength. In cases where heat treatment is not available, it was observed that the required strength criteria can be met with standard water curing as well. UHPC with a compressive strength of 170 MPa, which has excellent workability, was developed. As a result of the study, optimum solutions were proposed for the widespread use of UHPC in the precast industry.

Environmental and Economic Life Cycle Assessment of Recycled Aggregates Concrete in the United Arab Emirates

This paper studies the potential environmental and economic impact of replacing natural aggregates (NA) with recycled aggregates (RA) in the production of different sustainable concrete mixes in the United Arab Emirates (UAE). A life cycle assessment (LCA) was carried out according to the methodology proposed by the international standards of the series ISO 14040. The performance of concrete mixes having a similar design compressive strength was evaluated. Results showed that the inclusion of steel fibers (SF) led to an increase in the global warming potential (GWP), whereas mixes with cement replacement by fly ash, slag, or microsilica recorded a reduction in GWP. Furthermore, SF-reinforced mixes created with 100% RA were at least three times more expensive than the NA-based control mix, while the cost of those with cement replacement by mineral additives was generally similar to that of the control. Material transportation was found to be a main contributor to the environmental and economic impacts, only second to cement, and its contribution increased with longer distances and steel fiber incorporation and decreased with RA replacement. To integrate these individual measures and select optimum mixes for various applications, multifunctional performance indices were developed. Research findings highlight the possibility to fully replace NA with RA (100%) while maintaining the performance and improving the economic and environmental impacts of concrete produced in the UAE.

Performance evaluation of steel slag high performance concrete for sustainable pavements

ABSTRACT This paper represents the results of a comprehensive experimental work on developing high performance concrete mixes containing different percentages of electric arc furnace steel slag (EAFSS) coarse aggregate (0, 25, 50, 75, and 100% by weight) for sustainable pavements. The use of steel slag powder (SSP) and silica fume (SF) as a mineral filler was also investigated. Mechanical properties of concrete such as compressive, splitting tensile and flexural strengths, modulus of elasticity, permeability, and thermal conductivity, were measured in the laboratory. The morphological and microstructural properties of the investigated steel slag were also determined. Finally, the field performance of the investigated concrete mixes was predicted using the AASHTOWare Pavement ME for a typical Jointed Plain Concrete Pavement (JPCP) system in terms of transverse cracking, faulting, and roughness. The results of this research indicate that, all investigated mechanical properties for steel slag mixes are better than the natural aggregate mix with optimum mechanical properties and performance for the concrete mix with 50% EAFSS. Using the SSP powder with or instead of SF did not show significant improvement in mechanical properties/performance. The results emphasise that EAFSS is a viable sustainable construction material for rigid pavements.

Development of high performance carbonatable concrete for steel slag valorization

This study presents a high performance carbonatable concrete (HPCC) for the valorization of large volume steel slag. HPCC mix is designed to possess closely-packed particle size distribution, in which steel slag accounts for 90% of the binder. HPCC mix exhibits high flowability with ease of workability. The compressive strength of HPCC mix after appropriate predrying treatment reaches 104.9 MPa and 173.7 MPa, respectively, after 12-hour and 7-day carbonation curing. This can be attributed to the additional densification from the precipitation of carbonation products to the already densified matrix, which can be visually and quantitatively illustrated from the examination of microstructure and pore characteristics, respectively. HPCC mix exhibits negligible moisture absorption which is comparable to ultra high performance concrete (UHPC) mix, indicating high resistance to the ingress of foreign deleterious agents. Moisture absorption of Carbonation-induced deformation of HPCC mix is much smaller in comparison to UHPC mix, and the volume stability of HPCC mix is improved as a result of the consumption of f-CaO and periclase during carbonating. Therefore, HPCC mix is a promising candidate for effective utilization of steel slag while maintaining a high performance.

Experimental Study on the Performance of Concrete Mix with Paper Waste, Waste Plastic, Quarry Dust, and Fly Ash

In recent years, concrete in the construction industry has rapidly increased worldwide, including developing countries like India. The raw materials required to produce such a quantity require huge depletion of natural resources. On the other hand, disposal of paper waste, fly ash, and plastic waste is one of the biggest problems faced by many countries, including India, the amount of waste collected and recycled is less compared to disposal quantity. The use of these wastes in concrete reduces the disposal of waste in nature. In this experiment work, the use of these wastes in the concrete has been studied. Preliminary tests like specific gravity, fineness modulus, and water absorption have been carried out on the materials. Various mix designs are prepared by partial replacement of cement with fly ash and paper pulp, and sand is completely replaced with the quarry dust, and coarse aggregate is replaced with shredded plastic waste to create sustainable concrete. A comparative study on the properties like slump cone, the weight of the cubes, compressive strength and split tensile strength, and feasibility of such concrete has been carried out. Results indicated that the weight of cubes started to decrease with the addition of waste. Compressive strength and split tensile strength show that the strength started to fall with the addition of plastic. The cost of concrete decreased with the addition of waste. 5 % of plastic waste in concrete and 3 % of paper pulp, and 5 % of fly ash is considered the optimal replacement percentage.

Evaluation of strength and durability assessment for the impact of Rice Husk ash and Metakaolin at High Performance Concrete mixes

Traditional concrete used within the manufacture of High-Performance Concrete (HPC) does not provide the essential consistency. To attain the expected workability, structural reliability, high strength, but durability under adverse environmental conditions, generally available concrete materials must be perfectly shaped to a significant level. available Metakaolin (MK) and Rice husk ash (RHA) acquired were used to replace cement by 0%, 5%mk + 10%rha, 7.5%mk + 10%rha, 10%mk + 10%rha, 5%mk + 12.5%rha, 7.5%mk + 12.5%rha, 10%mk + 12.5%rha, 5%mk + 15%rha, 7.5%mk + 15%rha and 10%mk + 15%rha of its weight in different proportioning. Integration of MK and RHA into concrete increases water requirements, when compared with the control ordinary Portland cement (OPC) blend, integration of MK and RHA greatly improves durability properties; thus, by use of MK and RHA will decrease cement consumption while improving the durability characteristics of concrete such as percentage of water absorption, sorpitivity test, effective porosity, permeability, resistance to acid and rapid chloride penetration tests. Hence, this research paper concludes with strength characteristics and durability parameters for MK and RHA based High Performance Concrete (HPC) mixes.

Mechanical and fracture properties of alkali activated concrete containing different pozzolanic materials

Environmental considerations have caused the alkali-activated slag (AAS) cements to emerge as a promising sustainable substitute for the ordinary Portland cement (OPC). This study is aimed to the results of some comprehensive experimental researches performed on the AAS concrete with different types of partial replacement of binder including fly ash, silica fume, and red mud in terms of mechanical and different-mode fracture properties. According to the results, all AAS concrete mixes made with mineral admixtures (except 70% fly ash) exhibited mechanical strength comparable to that of the OPC concrete, and results of the fracture toughness in pure mode I (tensile opening), mode II (shear in-plane), and results of the fracture toughness in pure mode I (tensile opening), mode II (shear in-plane) and mode III (shear out-plane) showed that the trend of tensile and shear performance of concrete mixes are nearly similar. Based on the results of pull-off adhesion test and image processing, the high paste strength in different AAS concrete mixes caused a better aggregates-paste bonding strength.

Material aspects of high performance concrete

High performance concrete envisages the better performance concrete in terms of strength and durability properties by the quality of constituent materials. The study emphasis on effect of mineral admixtures such as fly ash and silica fume in high performance concrete. The high performance concrete of grade M60 is prepared with replacement of 10%, 20% and 30% of cement by fly ash and 2 % and 4% of cement by silica fume as mineral admixtures of desired mix proportions as per IS 10262-1982. The chemical admixture of conplast SP430, superplasticizer of 1% is added to ensure better workability for high performance concrete mix. The mechanical properties like workability, compressive strength and split tensile strength for all different cases were studied and the results are compared to find the optimum performance of fly ash and silica fume content. The optimal percentage of fly ash is about 20% with 4% silica fume to have better strength properties.

Performance of Concrete Mixes Using Marble Waste and ISF Slag

A high volume of marble production generate a considerable amount of waste in the form of odd sizes of stones and slurry during the mining, processing and polishing stages that has a serious impact on the environment. Imperial Smelting Furnace (ISF) slag is a waste generated in the primary extraction of zinc by a pyro metallurgical process with a granular texture. The main goal of this study is utilization of marble mining waste as a partial replacement for conventional coarse aggregate and ISF slag as a partial replacement for sand in concrete mixes. The concrete mixes were designed by using particle packing density approach with a constant water/cement ratio 0.5. In this study the natural coarse aggregate was replaced by 75% marble aggregate and natural sand was replaced by 40% ISF slag by weight. The results of the study show that, the mechanical and durability properties of concrete mixes using these wastes did not have significant adverse impact on properties of concrete.

Data Mining Techniques For Prediction Of Concrete Compressive Strength (CCS)

The main aim of this research is to use data mining techniques to explore the main factors affecting the strength of concrete mix. In this research, we are interested in finding some of the factors that influence the high performance of concrete to increase the Concrete Compressive Strength (CCS) mix. We used Waikato’s Knowledge Analysis Environment (WEKA) tool and algorithms such as K-Means, Kohonen’s Self Organizing Map (KSOM) and EM to identify the most influential factors that increase the strength of the concrete mix. The results of this research showed that EM is highly capable of determining the main components that affect the compressive strength of high performance concrete mix. The other two algorithms, K-Means and KSOM, were noted to be an advanced predictive model for predicting the strength of the concrete mix.