Compressive Strength Results Research Articles

Mechanical Characterization of MWCNT-Reinforced Cement Paste: Experimental and Multiscale Computational Investigation.

Computational approaches could provide a viable and cost-effective alternative to expensive experiments for accurately evaluating the nonlinear constitutive behavior of cementitious nanocomposite materials. In the present study, the mechanical properties of cement paste reinforced with multi-wall carbon nanotubes (MWCNTs) are examined experimentally and numerically. A multiscale computational approach is adopted in order to verify the experimental results. For this scope, a random sequential adsorption algorithm was developed to generate non-overlapping matrix-inclusion three-dimensional (3D) representative volume elements (RVEs), considering the inclusions as straight elements. Nonlinear finite element analyses (FEA) were performed, and the homogenized elastic and inelastic mechanical properties were computed. The use of a multiscale computational approach to accurately evaluate the nonlinear constitutive behavior of cementitious materials has rarely been explored before. For this purpose, the RVEs were analyzed both in pure tension and compression. Young's modulus as well compressive and tensile strength results were compared and eventually matched the experimental values. Moreover, the effect of MWCNTs on the nonlinear stress-strain behavior of reinforced cement paste was noted. Subsequently, three-point bending tests were conducted, and the stress-strain behavior was verified with FEA in the macro scale. The numerical modeling reveals a positive correlation between the concentration of MWCNTs and improved mechanical properties, assuming ideal dispersion. However, it also highlights the impact of practical limitations, such as imperfect dispersion and potential defects, which can deteriorate the mechanical properties that are observed in the experimental results. Among the different cases studied, that with a 0.1 wt% MWCNTs/CP composite demonstrated the closest agreement between the numerical model and the experimental measurements. The numerical model achieved the best accuracy in estimating the Young's modulus (underestimation of 13%), compressive strength (overestimation of 1%), and tensile strength (underestimation of 6%) compared to other cases. Overall, these numerical findings contribute significantly to understanding the mechanical behavior of the nanocomposite material and offer valuable guidance for optimizing cement-based composites for engineering applications.

Silica fume activated by NaOH and KOH in cement mortars: Rheological and mechanical study

Ordinary Portland cement (OPC) is the most used binder in the world, applied in practically all phases of the building. The problem is that this binder is highly harmful to the environment due to its production stage, which involves clinkerization by burning limestone. In this context, the objective of this work was to evaluate the potential of using silica fume as a partial substitute for cement, however verifying its activation potential. Silica fume is widely used as a pozzolanic material. In this work, the use of the material as alkali cement activated with sodium and potassium hydroxide (NaOH and KOH) was tested. The methods used consist of producing mortars in the compositions 1:3:0.60 (OPC: natural sand: water) and replacing the OPC with silica fume (10 and 20%) in three ways: i) without activation, as a pozzolanic material; (ii) activated by NaOH; and (iii) activated by KOH. Cylindrical specimens measuring 50x100 cm were produced, containing 0, 10 and 20% silica fume replacing OPC. Properties were evaluated in the fresh state, such as depth of penetration, consistency and squeeze flow, and tests in the hardened state, such as water absorption, density, and compressive strength. The results in the fresh state indicate that the compositions containing NaOH accelerate the setting process, but without impairing the workability of the mortar before the hardening process. The results of the fresh state of the compositions containing KOH indicate that the dissolution of this material is not as efficient in the cement medium in the first minutes after mixing the material. This impairs the workability of the mortar. In the hardened state, the density and water absorption results showed the occurrence of alkaline activation of silica fume. The results of compressive strength and diametral compressive strength were better for the compositions with NaOH and KOH, due to the occurrence of alkaline activation of silica fume which provided the formation of tobermorite and zeolites. Therefore, as an improvement this work concluded that the use of hydroxides together with the pozzolanic material silica fume is a more efficient way of replacing OPC than the isolated use of pozzolan, due to the occurrence of the alkaline activation process.

Predicting compressive strength of eco-friendly plastic sand paver blocks using gene expression and artificial intelligence programming

Plastic sand paver blocks provide a sustainable alternative by using plastic waste and reducing the need for cement. This innovative approach leads to a more sustainable construction sector by promoting environmental preservation. No model or Equation has been devised that can predict the compressive strength of these blocks. This study utilized gene expression programming (GEP) and multi-expression programming (MEP) to develop empirical models to forecast the compressive strength of plastic sand paver blocks (PSPB) comprised of plastic, sand, and fibre in an effort to advance the field. The database contains 135 results for compressive strength with seven input parameters. The R2 values of 0.87 for GEP and 0.91 for MEP for compressive strength reveal a relatively significant relationship between predicted and actual values. MEP outperformed GEP by displaying a higher R2 and lower values for statistical evaluations. In addition, a sensitivity analysis was conducted, which revealed that the sand grain size and percentage of fibres play an essential part in compressive strength. It was estimated that they contributed almost 50% of the total. The outcomes of this research have the potential to promote the reuse of PSPB in the building of green environments, hence boosting environmental protection and economic advantage.

Mechanical Properties of Polyamide Fiber-Reinforced Lime–Cement Concrete

Lime–cement concrete (LCC) is a type of lime-based concrete in which lime and cement are utilized as the main binding agents. This type of concrete has been extensively used to construct support layers for shallow footings and road backfills in some warm regions. So far, there has been no systematic research conducted to investigate the mechanical characteristics of polyamide fiber-reinforced LCC. To address this gap, LCC specimens were prepared with 0%, 0.5%, 1%, and 2% of polyamide fibers (a synthetic textile made of petroleum-based plastic polymers). Specimens were then cured for 3, 7, and 28 days at room and oven temperatures. Then, the effects of the fibers’ contents, curing conditions, and curing periods on the mechanical characteristics of LCC, such as secant modulus, deformability index, bulk modulus, shear modulus, stiffness ratio, strain energy, failure strain, strength ratio, and failure patterns, was investigated. The results of the unconfined compressive strength (UCS) tests showed that specimens with 1% fiber had the highest UCS values. The curing condition and curing period had significant effects on the strength of the LCC specimens, and oven-cured specimens developed higher UCS values. The aforementioned mechanical properties of the LCC specimens and the ability of the material to absorb energy significantly improved when the curing period under the oven-curing condition was increased, as well as through the application of fibers in the mix design. Based on the test results, a simple mathematical model was also established to forecast the mechanical properties of fiber-reinforced LCC. It is concluded that the use of polyamide fibers in the mix design of LCC can both improve mechanical properties and perhaps address the environmental issues associated with waste polyamide fibers.

The Effect of Existing Soil on the Unconfined Compressive Strength (UCS) Value on Cement Treated Recycling Base (CTRB) Type Flexible Pavement

Recycling technology or Cement Treated Recycling Base (CTRB) is one method for repairing damage to ancient road pavements, however, when the process is in place (Mixed in place), difficulties can arise, such as mixing with existing soil material that shouldn't be mixed in its implementation. because this will affect the results of Unconfined Compressive Strength (UCS). As a binder in the form of local cement from South Kalimantan, the brand is cheaper because production costs are cheaper. This study aims to obtain UCS Results at minimal cement levels that still meet the requirements with the use of brand local cement, obtain the typical influence of existing soil on UCS and what percentage of existing soil material can still be tolerated either curing or non-curing and correlation and get recommendations for the maximum percentage of influence of percent of existing land on UCS in curing or non-curing conditions. RAM samples were obtained for the purpose of investigation, which was done in a lab, existing soil and additional materials in the field. Inspection of old aggregates, making test specimens with variations in cement content of 1-10%, after obtaining minimum UCS according to technical requirements then making test specimens with variations in soil examinations and soil content of 0%, 5%, 10%, 15%, 20%, and 25% again then conducting data analysis to find correlations / relationships. The results of the research showed variances in cement content of 1% (one) - 10% that still meet the technical specifications of UCS (at least 30 kg/cm²) obtained a minimum cement content of 5% (five percent) with a UCS of 33.77 kg/cm². Then the test results of the influence of existing soil on UCS that is still tolerated are mixed, namely in curing conditions is 17% with the equation Y = -0.10075 x + 46.894 (R2 = 0.964). and non-curing 8.9% with the equation Y = -0.1113 x + 39.814 (R2=0.956). The R2 conclusions for both indicate a very There is a substantial correlation between the two factors

PENGARUH ABU TULANG SAPI SEBAGAI BAHAN TAMBAH AGREGAT HALUS DALAM PEMBUATAN BETON READY MIX

ABSTRACT
 In this study the authors aimed to determine the effect of using beef bone aggregate as an added ingredient for sand (fine aggregate) as well as an added ingredient for making ready mix concrete. The percentage levels of beef bones used in this study were 4%, 6% and 17%. In the manufacture of the test object is done by mixing the binder (cement), sand (fine aggregate and cow bone ash), gravel (coarse aggregate) and water using the experimental method. Samples of specimens were made using cylindrical molds (molds) and treated. The concrete compression test was carried out using a press machine, the mix design plan for making concrete was planned at 30 MPa. The total test objects made in this study were 20 pieces. The results of the test object with a cow bone ash content of 4% obtained compressive strength results of 7.58MPa 8.775 MPa 11.21 MPa 10.92 MPa and 10 MPa with an average value of 9.7 MPa. From the results of the addition of 6% beef bone ash, the results were 9.79 MPa, 9.73 MPa, 8.03 MPa, 9.23 MPa and 13.36 MPa and an average value of 10 MPa, for results with an addition of 17% cow bone ash was 10.3 MPa, 18.11 MPa, 15.28 MPa, 16.53 MPa and 19.13 MPa with an average yield of 15.87 MPa
 Keyword: Concrete, Cow Bone Ash, Compresive masive, Aggregate.

Analysis of the properties of chemically bound phosphate ceramics (CBPCs) produced from metakaolin with various acid phosphates

In this study, chemically bound phosphate ceramics (CBPCs), a type of geopolymer, were synthesized by reacting metakaolin (MK) with acidic solutions of phosphoric acid (PA), potassium dihydrogen phosphate (KDP), calcium dihydrogen phosphate (CDP), and aluminum dihydrogen phosphate (ADP). The obtained CBPCs were characterized using thermal analysis (DTA-TG), X-ray diffraction, dilatometry, and scanning electron microscopy and by their real density, porosity, water absorption, and compressive strength. The analyses revealed that the used acid phosphate type strongly influenced the properties of the resulting CBPCs. The best compressive strength results were found in CBPCs obtained using ADP, with an average value of 34.50 MPa and average porosity of 23.21%. For CBPCs obtained from PA, CDP, and KDP, the average compressive strength values were 14.18, 8.17, and 2.84 MPa, respectively; their average porosities were 18.79%, 36.23%, and 37.90%, respectively. The results demonstrate that CBPCs produced with MK can be cured at room temperature and that CBPCs obtained with ADP have higher compressive strength values than these of the other acids.

Mechanical, durability and sustainability assessment of rendering mortar with synergistic utilisation of recycled concrete and ceramic insulator fine aggregates

In alignment with Sustainable Development Goals (SDGs) set by United Nation, this study investigates eco-friendly alternatives which can be used in various construction activities. This research explores the potential of utilising recycled concrete fine aggregates (RCFA) and Ceramic Insulator Fine Aggregates (CIFA) as a complete substitute for natural river sand in rendering mortar applications, thoroughly examining mechanical and durability properties. The initial results demonstrated that the mortar mix made using 50% replacement of river sand with RCFA showed comparable results of compressive strength when compared with the control mix containing only river sand. However, the results of shrinkage and durability demonstrated the adverse effects of the use of RCFA in mortar with shrinkage being almost double to that in control mix. In order to enhance the performance of the mortar, the CIFA were added along with 50% RCFA. The addition of 50% CIFA along with 50% RCFA resulted in overall better performance with approximately 25% and 10% increase in compressive and adhesive strength, respectively. Additionally, the waste-incorporated mortar also outperforms the control mix in durability tests involving exposure to 5% HCL and H2SO4 solutions over 180 days. The results showed 2–3% lower mass and compressive strength loss compared to control mix indicating the better mechanical and durability performance of mortar mix. The SEM and XRD microstructure analysis techniques were also made use to further validate the mechanical and durability findings. To assess the sustainability of the mortar mixes, life cycle assessment (LCA) was conducted with a “cradle to gate” boundary condition. Furthermore, the Analytical Hierarchy Process (AHP) was employed to evaluate and rank the various mortar mixes based on their mechanical, functional (shrinkage and adhesive strength) and durability properties, along with sustainability indicator. The results of the AHP reveals that the mortar mix with 100% waste incorporation ranks first among all the other alternatives, highlighting its potential as an effective and sustainable option compared to conventional rendering mortar.

Investigation on mechanical and of Sri Lankan timber species for construction applications

Timber has been a prominent construction material for construction from the beginning of human civilization. The research aims at investigating the mechanical properties and durability (against chemical attack) of locally sourced wood species to be used in the construction industry. Authentication test of species, specific gravity, durability, compressive strength, bending strength, tensile strength and shear strength tests were conducted for locally available timber species. From the 34 species investigated, 24 species were observed to have viable properties to be used as softwood and hardwood timber in construction. After being exposed to sulfuric testing, compressive strength results (parallel to grain) of Pihibiya (Filicium decipiens) and Muttikadol (Xylocarpus granatum) were only reduced by 4.3% and 1.6%, respectively. This is evidence of the two species having strong chemical resistivity. Bala, Katta Kumanjal, Muttikadol, Wal Jambu, Karambu, Malkaralla and Thammanna were identified as underutilized timber species in the local context, having bending strengths over 25 N/mm2. Overall, this research is important for the international society as it contributes to sustainable resource management, economic development, environmental conservation, standardization, and knowledge exchange.

Effects on jute fiber and ferrochrome slag as coarse aggregate on mechanical properties of reinforced concrete

The present research work aims to produce by adding jute fiber (JF) with ferrochrome slag (FSA) as coarse aggregate. The experimental results of all the properties of jute fiber with ferrochrome slag (FSA) based concrete are compared to controlled concrete and efficient, technically acceptable and environmentally compatible construction material. From compressive strength, flexural strength and split tensile test results, it is observed that ferrochrome slag -based concrete samples' incorporation of jute fiber shows better performance than that of controlled concrete. Further, non -destructive tests and co-relation between compressive strength with split tensile strength and flexural strength are performed. This study focuses on the reuse of waste ferrochrome slag as a partial replacement for coarse aggregate in the production of cement concrete with improved mechanical properties and non-destructive tests. Ferrochrome slag was replaced by coarse aggregate with various percentages ranging from 0%, 50% and 100% by adding 0.10%, 0.20% and 0.30% JF (by weight). The workability test was performed to evaluate the concrete behaviour in a fresh state. The result shows that adding the percentages of jute fiber up to 0.10% shows 4.83%, 3.2% and 3.4% more compressive, split and flexural strength than the control concrete.

A machine learning-based genetic programming approach for the sustainable production of plastic sand paver blocks

Plastic sand paver blocks (PSPB) provide a sustainable alternative by reprocessing plastic waste and decreasing reliance on environmentally hazardous materials such as concrete. They promote waste management and environmentally favorable building practices. This paper presents a novel method for estimating the compressive strength (CS) of plastic sand paver blocks based on gene expression programming (GEP) techniques. The database collected from the experimental work comprises 135 compressive strength results. Seven input parameters were involved in predicting the CS of PSPB, namely, plastic, sand, sand size, fiber percentage, fibre length, fibre diameter, and tensile strength of the fibre. Simplified mathematical expressions were used to figure out the CS. The results of GEP formulations showed that they were better in line with the experimental data, with R2 values for CS of 0.89 (training) and 0.88 (testing). The models' performance was evaluated using sensitivity analysis and statistical checks. The statistical evaluations show that the actual and predicted values are closer together, which lends credence to the GEP model's capacity to forecast PSPB CS. The sensitivity analysis showed that sand size and fibre percentage contribute more than 50% of the CS in PSPB. In addition, the results demonstrate that the proposed models are accurate and have a robust capacity for generalization and prediction. This research can improve environmental protection and economic benefit by enhancing the reuse of PSPB in producing green ecosystems.

PENGARUH PEMANFAATAN AIR EKSTRAKSI ECENG GONDOK TERHADAP KUAT TEKAN BETON K-175

This study aims to determine the compressive strength value of K-175 concrete with variations in theaddition of water hyacinth extraction water. The research method used was a laboratory experiment, bydetermining the cement water factor and the composition of the new mixture. In this study, 24 cube testobjects were made using variation of water hyacinth extrac mixtures of 1%, 3% and 5%. The results of thisstudy were the compressive strength value of the average normal K-175 concrete at the age of 14 and28days the compressive strength results were 144.3 kg/cm2 and 184.3 kg/cm2, while the compressive strengthwith variations in the addition of 1% water hyacinth extraction water was of 154.8 kg/cm2 and196.4 kg/cm2, variations in the addition of 3% water hyacinth extraction water was 164.7 kg/cm2 and212.3 kg/cm2, while for variations in the addition of 5% was 149.6 kg/cm2 and 193.4 kg/cm2. The optimumcompressive strength obtained in this study was the variation of 3% water hyacinth extracti mixture for theage for 28 days of age, which was 212.3 kg/cm2.

Efficacies of suggested strength-based prediction models for estimation of compressive and tensile properties of normal concrete

One of the most crucial challenges faced by today’s construction industry for a speedy delivery is undeniably the ‘time-factor’ accompanied by promised quality within the framework of distinct budget. Strength based - Prediction models helps in estimating the early strengths as well as later-stage strength or strength at any age of concrete. Such models assist the structural and execution engineers in arriving at a fair judgement of compressive strength of concrete. A normal practice usually followed by the material testing laboratories and quality assurance cell at site is to assess the cube compressive strength of concrete which is an intrinsic engineering property governing the design and performance phase of structures. It is found from the literature that most of the prediction models that are formulated to estimate the compressive strength of concrete at any age are actually based on cylinder compressive strength of concrete. Therefore, this paper attempts to use some of the suggested prediction models with two sets of data, that is, one by considering experimental results of cube compressive strength found at the age of 7, 14 and 28-days and two by utilizing a conversion value, suitable cylinder compressive strength is obtained. These datasets are thoroughly used in the prediction models to accurately estimate the compressive strength of concrete. Similarly, appropriate prediction models are sought to determine the split tensile strength of normal concretes based on cubic compressive strength and cylinder compressive strength. Particularly, results of the present study showcase that although the prediction models are developed based on cylinder compressive strength, they can agreeably be used on cube strength data as the ratio of (Pi/Ai) obtained is the higher range of 0.85-1.00 and with only an early cube strength result, it is possible to predict an accurate value of split tensile strength of concrete at an age of 28-days. The effectiveness of suggested prediction models through statistical parameters are determined and their efficiencies are found to be in the higher range of 94% to 98%.

Effect of Si/Al molar ratio and curing temperatures on the immobilization of radioactive borate waste in metakaolin-based geopolymer waste form

Immobilization of radioactive borate waste (RBW) using a geopolymer with a high Si/Al ratio has been challenging because boron-silicon networks lower the compressive strength and delay the setting time. In this study, metakaolin-based geopolymer waste form to immobilize simulant RBW was fabricated using different Si/Al ratios (1.0–1.4) and curing temperatures (26 and 60 ℃). The 7-day compressive strength results revealed that a certain amount of silicon and an elevated curing temperature are required to achieve high compressive strength and waste loading. Following waste acceptance criteria tests, all geopolymers exhibited compressive strengths higher than 3.445 MPa. The leachability index of boron was higher than 6.0, and the leaching mechanism was identified as diffusion. No significant structural changes in the geopolymer were observed after thermal cycling and gamma irradiation tests. The physically bound or unincorporated RBW was leached out of the geopolymer during water immersion and leaching tests; however, boron, which was chemically connected with silicon, was present as an inert phase together with a geopolymer binder. Consequently, immobilizing RBW using a geopolymer with a low Si/Al ratio (1.4) is beneficial in terms of RBW loading and structural durability.

PENGARUH PEMANFAATAN AIR EKSTRAKSI ECENG GONDOK TERHADAP KUAT TEKAN BETON K-175

This study aims to determine the compressive strength value of K-175 concrete with variations in theaddition of water hyacinth extraction water. The research method used was a laboratory experiment, bydetermining the cement water factor and the composition of the new mixture. In this study, 24 cube testobjects were made using variation of water hyacinth extrac mixtures of 1%, 3% and 5%. The results of thisstudy were the compressive strength value of the average normal K-175 concrete at the age of 14 and28days the compressive strength results were 144.3 kg/cm2 and 184.3 kg/cm2, while the compressive strengthwith variations in the addition of 1% water hyacinth extraction water was of 154.8 kg/cm2 and196.4 kg/cm2, variations in the addition of 3% water hyacinth extraction water was 164.7 kg/cm2 and212.3 kg/cm2, while for variations in the addition of 5% was 149.6 kg/cm2 and 193.4 kg/cm2. The optimumcompressive strength obtained in this study was the variation of 3% water hyacinth extracti mixture for theage for 28 days of age, which was 212.3 kg/cm2.

Sustainably produced concrete using weathered Linz-Donawitz slag as a fine aggregate Substitute: A comprehensive study with Artificial intelligence approach

Continuous consumption of natural resources such as river sand and coarse aggregates due to increased industrialization and urbanization has impeded the movement towards green concrete in construction, i.e., utilizing waste materials in its production, steel slag waste being one of them. Accumulation of Linz-Donawitz slag (LD slag) has become cumbersome in India, posing a problem of landfills and environmental degradation, i.e., abating soil and water quality due to the leaching of toxic metals. Fewer experimental studies have examined whether weathered fine LD Slag can substitute for fine aggregates in concrete. Additionally, the research has yet to compare the behavior of concrete comprising weathered fine LD slag in Normal Strength Concrete (NSC) and High Strength Concrete (HSC) containing Metakaolin. The current study aims to establish an optimum replacement quantity for fine aggregates with fine LD slag. The slag replaced fine aggregates by volume at 25, 50, 75 and 100%. The findings that examined the effects of using LD slag on the mechanical behaviour, durability and microstructure of concrete are presented in this study. Furthermore, taking a total of 180 experimental data points, the compressive strength of concrete was predicted using artificial intelligence (AI) methods such as Artificial Neural Networks (ANNs), Decision Trees (DT) and Random Forests (RF). Coefficient of determination R2, Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were computed to assess the performance of generated models. Besides, a sensitivity analysis technique was employed to determine the most influential parameter among cement, Metakaolin, Fine Aggregate, Coarse Aggregate, LD slag, Superplasticizer, water content and testing age on the compressive strength results. Experimental investigation showed that adding LD slag up to 50% for NSC and 25% for HSC was optimal and showed better results for tested properties than conventional concrete mixes. Among proposed AI techniques, the DT technique was the best-performing model with an R2 value of 0.973 and the least for MAE (3.534 MPa) and RMSE (4.409 MPa). Sensitivity analysis performed on the DT model showed that testing age was the most critical parameter for the prediction of compressive strength.

The comparison of the experimental investigations of strength characteristics of conventional and bacterial concrete

Conventional concrete (CC) is the greatest used construction material in the world, especially in aggressive environments. This is due to the element's size and shape. The world's consumption of concrete is on the order of 5.5 billion metric tons a year. The advancement of concrete technology, as well as the development of materials and mechanisms, has resulted in increased strength needs. Maintenance, repair, and rehabilitation of present concrete structures challenge a lot of difficulties, resulting in significant expenditure. Concrete is vulnerable to microcracks creation and has extremely undesirable pores. Hence, there is an urgent need to pay more attention to improving the properties of concrete in terms of strength. The effective remedy for the closure of cracks is Bacterial concrete (BC) which will constantly be in concrete and this phenomenon is called Microbiologically Induced Calcite Precipitation (MICP). The urease enzyme enables the deposition of calcium carbonate (CaCO3) with the advantage of bacteria. The bacterial remediation technique exceeds added techniques. The examinations were carried out with variety an of quantitative evaluations of the optimal concentration of bacterial cells to be collected in concrete. Based on the state-of-the-art evidence obtainable in the literature, in these existing soundings two different bacterial illustrations specifically Bacillus Megaterium (BM) and Bacillus Subtilis (BS) are measured in concentrations of 104, 105, and 106 cells/ml of mixing of water. The optimum amount of cell concentration of bacteria is created to be 104 cells/ml for BM and 105 cells/ml for BS based on the results of compressive strength. This investigation is carried out on strength-related properties such as compressive strength, splitting tensile strength, and flexural strength. It is determined that BM and BS bacteria can be firmly used for refining the performance and strength characteristics of concrete.

The ratio between flexural strength to compressive strength of geopolymer concrete

Building infrastructure always chooses to use strong materials, low costs, easy maintenance and easily available materials. One of these materials is normal concrete which is one of the normal concrete making materials using Portland cement. The process of making Portland cement can cause damage to the environment due to greenhouse emissions, so research is needed to create environmentally friendly concrete, one of which is geopolymer concrete. In geopolymer concrete there is still not too much research done when compared to normal concrete. In this study want to know the relationship between the compressive strength results and the flexural strength results in geopolymer concrete which is represented by a formula in the form of a ratio of the results of the two tests. The ratio obtained from the study will be compared with the ratio of ACI 318 0.62. The compressive strength test used a cylindrical specimen with a size of 15×30 cm and a flexural strength test used a beam-shaped test object with a size of 53×15×15 cm. The results of the research that have been carried out have obtained the ratio of compressive strength and flexural strength in geopolymer concrete 0.477 where the ratio value is below the ratio set by ACI 318.

Eco-efficient biowaste and aqua waste as cementitious material in high performance concrete

The energy requirements and environmental impact of cement manufacture are key issues today. Over the years, much research has been done to improve the resilience and sustainability of the cement industry as well as to offset its carbon emissions. This work used pozzolanic materials, corncob ash (CCA), and crab shell powder (CSP) to partially replace ordinary Portlandcement in concrete mixtures. The performance of concrete mixed with agricultural and aquaculture additives was assessed by replacing the cement. Compressive strength tests were carried out on concrete specimens in which cement was replaced by agricultural and aquacultural wastes. Furthermore, microstructural analysis was conducted to understand the morphology and chemical phases in the concrete specimens blended with supplementary cementitious materials. Concrete specimens combined with agricultural and aquatic-based additives show higher compressive strength results. In contrast to the specimens mixed with corn cob ash, crab shell powder demonstrates significant strength at lower dosages. The rich silica enhances pozzolanic reaction, which helped improve the thick phases of the concrete matrix. It can be concluded that concrete made from agricultural and aquatic sources can serve as a sustainable substitute for ordinary Portland cement and a strength booster, providing a new type of building material and promoting environmentally friendly construction.

PERFORMANCE OF TERNARY CEMENT MORTAR USING STEEL SLAG, FLY ASH, AND METAKAOLIN

Green mortar is a mortar that is environmentally friendly and that uses waste materials or by-products to reduce CO2 emissions that are produced during cement production. This study aims to produce a new type of green mortar by using ternary cement mixes with acceptable fresh and hardened properties. The materials used were metakaolin (10-20%), slag (15-30%), and fly ash (10-20%). The experimental work was divided into two steps. Firstly, metakaolin was replaced with various percentages of 10%, 15%, and 20%, and then the optimum percentage having the highest compressive strength was chosen to use in ternary mixes. Secondly, cement was replaced with a ternary mix (slag, fly ash, and metakaolin) with a replacement ratio of 40% and 50%. Properties were studied flowability, compressive strength, flexural strength, water absorption, dry density, ultra-sonic plus velocity test, The results show that using metakaolin as a partial replacement for cement decreased flowability and increased superplasticizer dosage. From the results can conclude the use of ternary mixes decreased the workability of mixes and increased the dosage of superplasticizers to 1.8% at 50% replacement of cement. The results of compressive strength showed an increase of 50.6% after replacing 10% metakaolin at 7 days and 17.35% after replacing ternary mixes with 15% slag, 15% fly ash, and 10% metakaolin, while flexural strength increased by 26.47% after replacing the same percent of metakaolin and by 10.4% after replacing a ternary mix with the same percent of materials. The results show that using 10% metakaolin decreased water absorption by 28.75% while increasing slag increased water absorption in ternary mixes. The results for dry density slightly decreased or increased with the increased replacement of ternary cement mixes from 1.2% to 0.33% compared with the control mix. The UPV test result increased by 5.4% in ternary cement mixes, and when replacing metakaolin with 10% and 15%, it increased UPV by 5.7% and 5.2%, respectively, at 28 days.