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The purpose of this study is to fit an appropriate mathematical model to express response variables as functions of the proportions of the mixture components. One purpose of statistical modeling in a mixture experiment is to model the blending surface such that predictions of the response for any mixture component, singly or in combination, can be made empirically. Testing of the model adequacy will also be an important part of the statistical procedure.

A series of mortar using air lime, marble and ceramic sanitary waste aggregates were prepared for statistically designed combinations. The combinations were designed based on the mixture-design concept of design of experiments; this mortar is often used as a filler material in restoration projects. The aim of this work is to find an optimal composition of a paste for the manufacture of air lime mortar with ceramic and marble waste. This investigation aims to recommend mix design for air lime-based mortar, by optimizing the input combination for different properties, and to predict properties such as mechanical strength, thermogravimetric and x-ray diffraction analysis with a high degree of accuracy, based on a statistical analysis of experimental data.

This paper discusses those mortar properties that architects, contractors and owners consider important. For each of these properties, the influence of ceramic and marble waste in the air lime mortar is explored. The flexibility of lime-based mortars with waste materials to meet a wide range of needs in both new construction and restoration of masonry projects is demonstrated.

The objective of the present investigation is to recommend mixture design for air lime mortar with waste, by optimizing the input combination for different properties, and to predict properties such as compressive strength, flexural strength with a high degree of accuracy, based on the statistical analysis of experimental data. The authors conducted a mixture design study that takes into account dependent parameters such as the constituents of our air lime-based mortar where we have determined an experiment matrix to which we have connected the two responses, namely, compressive and flexural strength. By introducing the desirability criteria of these two responses, using JMP software, we were able to obtain a mixture optimal for air lime mortar with ceramic and marble waste.

This study aims to present the results of an experimental evaluation of low (M30), mid (M40) and high (M50) grade self-compacting concrete (SCC) with three nominal maximum aggregate sizes (NMAS), namely, 20 mm, 16 mm and 12.5 mm, with Bailey gradation (BG) in comparison with Indian standard gradation (ISG).

This study was conducted in a laboratory by testing the characteristics of fresh and hardened properties of self-compacting concrete.

Rheological and mechanical properties of SCC were evaluated in detail and according to the results, a concrete sample containing lower NMAS with BG demonstrated improvement in modulus of elasticity and compressive strength, while improving the rheological properties as well. Meanwhile, SCC demonstrated poor performance in split tensile and flexural strengths with lower NMAS gradations and a direct correlation was evident as the increase in NMAS caused an increase in the strength and vice-versa.

Upon comparison of BG with ISG, it was revealed that BG mixes succeeded to demonstrate superior performance. From the material optimization, rheological and mechanical performance study, it is recommended that BG with NMAS 16 mm can be used for conventional SCC.

The purpose of this paper is to study the effect of nano alumina (Al₂O₃) on the properties of fresh concrete, hardened concrete and microstructure of concrete incorporated with high range water reducer (HRWR). This initiative was taken to improve characteristic properties of concrete using nano alumina because nano alumina can be easily be manufactured from a scrap of industrial aluminum products, so its incorporation in concrete will not only reduce industrial aluminum waste but will also change the morphology of concrete at the microstructural level.

To accomplish the objectives of the research, four different concrete mixes with the constant water–cement ratio (W/C) and superplasticizer (SP) content 0.4 and 0.6% by weight of cement, respectively, were prepared, whereas nano alumina content was altered by 0.3% and 0.4% by weight of cement. Fresh property of concrete was analyzed by using slump cone test, whereas hardened properties of concrete were analyzed through compression test and flexural strength test. The interaction of nano alumina with concrete composite was evaluated using an X-ray diffraction test.

It was observed that 0.6% superplasticizer by weight of cement increased workability by 22% but with the addition of 0.3%, nano alumina by weight of cement workability decreased by 31%. Compressive strength increased by 4.88% with the addition of 0.6% superplasticizer but with the addition of 0.3% nano alumina by weight of cement compressive strength increased by 18.60%. Also, flexural strength increased by 1.21% with the addition of 0.6% superplasticizer by weight of cement but with the addition of 0.3% nano alumina by weight of cement flexural strength increased by 8.76%. With the addition of superplasticizer, alite and belite phases remained un-hydrated but with the addition of nano alumina alite phase was hydrated while belite phase was un-hydrated. The size of belite crystals in mixes having nano alumina was less than that of mix having 0.6% superplasticizer. Also with the addition of nano alumina, a calcium aluminum silicate phase was formed which was responsible for the increment of strength in mixes having nano alumina.

Incorporation nano alumina (Al₂O₃) in concrete will not only reduce industrial aluminum waste but will also reduce CO₂ emission. Nano alumina (Al₂O₃) also changes morphology of concrete at micro structural level.

The purpose of this paper is to implement the mathematical models to predict concretes physico-mechanical characteristics made with binary and ternary sands using a mixture design method. It is a new technique that optimizes mixtures without being obliged to do a lot of experiments. The goal is to find the law governing the responses depending on mixture composition and capable of taking into account the effect of each parameter separately and in interaction between several parameters on the characteristics studied.

Mixture design method was used for optimizing concretes characteristics and studying the effects of river sand (RS), dune sand (DS) and crushed sand (CS) in combinations of binary system and ternary on workability, the compressive and flexural strengths of concretes at 7 and 28 days. A total of 21 mixtures of concrete were prepared for this investigation. The modeling was carried out by using JMP7 statistical software.

Mixture design method made it possible to obtain, with good precision, the statistical models and the prediction curves of studied responses. The models have relatively good correlation coefficients (R² = 0.70) for all studied responses. The use of binary and ternary mixtures sands improves the workability and their mechanical strengths. The obtained results proved that concrete, based on binary mixture C15, presents the maximum compressive strength (MCS) on 28 day with an improvement of around 20%, compared to reference concrete (C21). For ternary mixtures, MCS on 28 day was obtained for the mixture C10 with an improvement of around 15% compared to C21. Increase in compressive strength during the progress of hydration reactions was accompanied by an increase in the flexural strength, but in different proportions.

The partial incorporation of DS (= 40%) in the concrete formulation can provide a solution for some work in the southern regions of country. In addition, the CS is an interesting alternative source for replacing 60% of RS. The concrete formulation based on local materials is really capable of solving the economic and technical problems encountered in the building field, as well as environmental problems. Local resources therefore constitute an economic, technological and environmental alternative.

The purpose of this paper is to investigate the potential use of construction and demolition waste materials (C&DWM) as an alternative for natural fine aggregates (NFA), in view to solve the disposal problems caused due to landfills. In addition, to evaluate its suitability as a sustainable material, mechanical and durability properties have been performed on different proportions of concrete blending and the results recorded were compared with the reference concrete values.

In this research, the NFA were replaced at the proportion of 25%, 50%, 75% and 100% of C&DWM with a constant slump range of 130 mm–150 mm. This parameter will assess the consistency of the fresh concrete during transportation process. The characteristics of the end product was evaluated through various tests conducted on hardened concrete samples, namely, compressive strength, flexural strength, depth of penetration of water under pressure, rapid chloride penetration test, carbonation test and ultrasonic pulse velocity (UPV) test. All results recorded were compared with the reference concrete values.

The results demonstrated that the use of C&DWM in concrete portrayed prospective characteristics that could eventually change the concept of sustainable concrete. It was noted that the compressive and flexural strength decreased with the addition of C&DWM, but nevertheless, a continuous increase in strength was observed with an increase in curing period. Moreover, the increase in rapid chloride penetration and decrease in UPV over time period suggested that the concrete structure has improved in terms of compactness, thus giving rise to a less permeable concrete. The mechanical tests showed little discrepancies in the final results when compared to reference concrete. Therefore, it is opined that C&DWM can be used effectively in concrete.

This study explores the possible utilisation of C&DWM as a suitable surrogative materials in concrete in a practical perspective, where the slump parameter will be kept constant throughout the experimental process. Moreover, research on this method is very limited and is yet to be elaborated in-depth. This approach will encourage the use of C&DWM in the construction sector and in the same time minimise the disposal problems caused due to in landfills.

Currently, many experimental studies on the properties and behavior of rubberized concrete are available in the literature. These findings have motivated scholars to propose models for estimating some properties of rubberized concrete using traditional and advanced techniques. However, with the advancement of computational techniques and new estimation models, selecting a model that best estimates concrete's property is becoming challenging.

In this study, over 1,000 different experimental findings were obtained from the literature and used to investigate the capabilities of ten different machine learning algorithms in modeling the hardened density, compressive, splitting tensile, and flexural strengths, static and dynamic moduli, and damping ratio of rubberized concrete through adopting three different prediction approaches with respect to the inputs of the model.

In general, the study's findings have shown that XGBoosting and FFBP models result in the best performances compared to other techniques.

Previous studies have focused on the compressive strength of rubberized concrete as the main parameter to be estimated and rarely went into other characteristics of the material. In this study, the capabilities of different machine learning algorithms in predicting the properties of rubberized concrete were investigated and compared. Additionally, most of the studies adopted the direct estimation approach in which the concrete constituent materials are used as inputs to the prediction model. In contrast, this study evaluates three different prediction approaches based on the input parameters used, referred to as direct, generalized, and nondestructive methods.

With a growing list of available materials and processes, the inherent mechanical and thermophysical properties of three-dimensional (3D) prints are important design targets. This paper aims to study the functionality of binder jet 3D printed objects for thermally activated building construction elements and recyclable formwork for concrete structures.

Binder jet printed sand samples with various material and post-processing parameters (infiltration and baking) are prepared and studied. Using a statistical experiment design, the mechanical (flexural and compressive strength) and thermal (conductivity and specific capacity) characteristics are quantified.

Relative to the unprocessed “green” print samples, post-processing improved the flexural and compressive strength of the samples by factors of 6.9 and 21.6, respectively; the thermal conductivity and specific heat capacity were improved by factors of 7.7 and 1.2, respectively. For the investigated temperature range (20°C–200°C), the “green” prints showed excellent stability while the stability of post-processed samples depended on the infiltrate used. Microscopic images of the microstructures offered evidence to support improvement in the mechanical and thermo-physical characteristics of the 3D printed sand elements.

The literature review concluded that optimal printing parameters and infiltration under vacuum could further improve the mechanical and thermo-physical properties of the binder jet printed elements. However, both these factors were not explored in this research. The statistical experimental design approach provided more flexibility to choose the number of experiments for a fixed amount of time and resources. However, for future work, a more extensive number of experiments and reproducibility testing for each combination of binder-infiltrate is recommended.

3D printing has been identified as a promising opportunity to reduce material usage and improve construction efficiency in the field of architecture and building engineering. The emerging fabrication technologies are further expected to significantly reduce the operational energy of buildings through performance integration, i.e. multi-functional building elements with integrated heat- and mass-transfer capabilities to replace conventional systems.

This study has quantified the impact of infiltration on the mechanical and thermo-physical characteristics of sand-printed elements and, as such, reports reproducible functional performance maps for sand-print applications. The research demonstrates a way to achieve the desired functional characteristics of 3D prints through combinations of material selection and process/post-processing parameters.

One of the most contested and anticipated research issues is the acceptability of using recycled aggregates instead of fresh aggregates. This study aims to look at the possibility of replacing fresh aggregates with 15%, 30%, 60% and 100% recycled aggregates.

The research is divided into two stages. The compressive, split tensile, flexural and bond strength of the various mixes were examined in the first phase using untreated recycled concrete aggregates (RCA). The second phase entails chemically treating RCA with a 10% 0.1 M sodium metasilicate solution to evaluate differences in strength, indicating the success of the treatment performed. Microstructural experiments such as scanning electron microscopy and X-ray diffraction were also conducted to evaluate the formation of interfacial transition zone (ITZ) in treated and untreated RCA specimens.

The observed findings reveal a decrease in concrete strength with increasing RCA concentration; however, when treated RCA was used, the strengths increased significantly when compared to untreated samples. The findings also include curves indicating the correlation between compressive strength and other mechanical strength parameters for an optimum mix of concrete prepared with 30% RCA replacement.

The study through its novel approach, demonstrates the effect of pretreatment of RCA in the absence of any standardized chemical treatment methodology and presents significant potential in minimizing reliance on fresh aggregates used in concrete, lowering building costs and promoting the use of waste materials in construction.

The purpose of this work is to improve the air entrainment capacity of a concrete by using fine mineral admixtures such as fly ash (FA) and silica fume (SF) as cement substitute, and coal bottom ash (CBA) as fine aggregate substitute. Air entrainment capacity has been studied indirectly as a measure of heat resistance of concrete. Literature has suggested that mineral admixtures improve the air absorption in the paste component of the concrete, on the one hand, whereas they perform pore and grain size refinement, on the other, thereby reducing the air entrainment. CBA, which being porous, creates the possibility of air adsorption by the aggregate component. Therefore, the study finds out whether a double benefit of adding both of these materials will be achieved, or CBA will try to improve the deficiency in the air entrainment created by the mineral admixtures.

Air-entrained concrete (AEC) mixes were constituted in three groups. First group represents mixes with natural fine aggregates only, and second with 25% fine aggregates substituted by CBA. Progressively, the third group has 50% fine aggregates substituted with CBA. In all the three groups, cement was substituted with FA and SF @ 0%, 20% and 40%, and 0%, 5% and 10%, respectively, thereby creating four binary and four ternary mixes corresponding to each group. Compressive and flexural strength tests were conducted at 28 days on the concrete mixes pre and post high-temperature heat treatment, i.e. 100°C, 200°C and 400°C, respectively. This study also examines the microstructure characteristics of AEC after 14 days of curing via X-ray diffraction. Sorptivity test was also conducted to estimate the capillary and air-entrained voids in concrete.

It was found that a concrete mix containing 20% FA and 10% SF along with 50% CBA could give similar post-heated strength to a normal (without mineral admixtures) AEC. In AECs where only CBA is present and cement paste is not substituted, both of the pre- and post-heated strengths of concrete reduce. Also, some mixtures containing large amounts of mineral admixtures in concrete with nil CBA show a high reduction in post-heated strength though they show good pre-heated strength. Therefore, mineral admixtures and CBA complement each other in improving the post-heated strength. Air pore structure found from sorptivity test also verifies these results.

AEC is very helpful for insulation of buildings during summer season by absorbing heat waves. AEC containing FA and CBA reduces carbon footprint because of substitution of cement and it also helps to conserve natural resources by the use of CBA in place of fine aggregates.

Seeks to examine the bond strength of a large range of structural polypropylene fibres, as used in concrete, to determine the most effective fibre capable of transmitting load (N/mm²) between fibre and cement within the concrete matrix.

Following fibre selection characterised by the highest bond strength, determined from a series of pull out tests, BS flexural tests were carried out using high bond strength fibres (40 mm × 0.9 mm diameter used at 6 kg/m³) to determine whether or not structural polypropylene fibres had any effect on the ultimate flexural strength of fibre‐reinforced concrete, when compared with the plain control sample. Fibre orientation, type of rupture failure mode and post‐crack performance were examined.

Even structural fibre dispersion was found to be best achieved with the use of monofilament polypropylene fibres (19 mm × 22 micron used at 0.9 × kg/m³) in addition to the 6 kg/m³ structural fibre dose. Structural polypropylene fibres were found not to provide additional flexural strength however, they did provide post‐crack control, limiting the crack width with subsequent enhanced durability that in turn will provide lower life cycle costs.

In addition to increased durability the use of fibre reinforcement negates the need to place steel reinforcement bars.

Investigates the ambiguity in literature between claims made by different investigators regarding the effects of polypropylene fibres on compressive and flexural strengths.