Normal Concrete Mix Research Articles

Enhanced nonlinear models for critical compressive stress-strain characteristics of rubberized concrete: Comprehensive experimental data and robust evaluation methodology

The integration of rubber aggregate (RA) into concrete presents a pivotal avenue for enhancing the material's sustainability and environmental impact. Despite its potential, a crucial gap persists in the field concerning the development of material models that accurately consider the influence of RA particle size on the stress-strain responses of Rubberized Concrete (RuC). To address this gap, this study explores the effects of incorporating RA into concrete on its ascending compressive stress-strain behavior. In this research, we have compiled a comprehensive database encompassing the compressive stress-strain characteristics of 80 distinct concrete mixes incorporating RA from varied sources, sizes, and attributes. The investigation also evaluated the effectiveness of recent models in predicting key parameters, including modulus of elasticity, peak stress, and strain at peak stress. We proposed more robust models to accurately capture essential features. Notably, the findings suggest that higher RA content leads to dispersed cracks and decreased stiffness, resulting in lower peak stress and strain. Moreover, compressive strength exhibits notable variations with RA content, with significant drops observed across both normal and high-strength concrete mixes. The performance evaluation of existing models underscores the superiority of Li et al.'s model for peak stress prediction and Abbara et al.'s model for elasticity modulus prediction. The proposed simplified nonlinear models in this research offer enhancements over existing ones, promising more accurate predictions. These findings have profound implications for the optimization of rubberized concrete mixes and pave the way for future research directions aimed at further refining predictive models and advancing the application of RA in concrete technology.

Mechanical Properties of Rigid Pavements Incorporating Different Percentage of Steel Fiber

Nowadays, rigid pavement construction has widely used in road construction industry. Although rigid pavement is widely used in road construction, it tends to fail within time due to many reasons. Fatigue is the important aspect in the rigid pavement design. Due to applications of the heavy loads fatigue occurs in the pavement in the form of micro cracks. Fatigue concepts which is an important parameter in cement concrete pavement and mainly failure occurs due to fatigue failure. As a result, it is crucial to optimize and improving concrete structures to suit diverse engineering requirements. This paper investigates the effect of steel fiber on the improvement of structural behavior such as compressive, tensile and also flexural stiffness performance of rigid pavements. In this respect, the concrete mix design accordance to Design of Normal Concrete Mix (DOE) method was employed in the preparation of the specimens. A series of concrete laboratory tests have been carried out to evaluate the mechanical properties of the concrete sample incorporating 1, 3 and 5% of steel fiber. As a result, the performance (compressive, tensile and flexural) of modified rigid pavements improved remarkably 15-60% with 5% additive of steel fibre at 7 and 18 days curing time. Based on these studies, the addition of steel fiber reinforcement into the rigid pavements has a significant effect on mechanical properties of reinforced concrete mixture.

Application of Coffee Husk Ash as Partial Replacement of Fine Aggregate in Concrete

The task of turning agricultural waste into practical construction and building materials has been placed before civil engineers. Coffee husk is produced in vast amounts due to the global commerce of coffee beans, which are incinerated into ash when used as fuel, producing coffee husk ash (CHA). Even though many researchers have worked on the utilization of CHA in concrete, they have been used as partial cement replacement but not as a replacement of aggregates. The experimental study of the performance of concrete on fine aggregate replaced partially with CHA is represented in this paper. The fine aggregate is replaced by 0%, 2%, 4%, 6%, and 8% by weight of CHA. The performance of the partially replaced fine aggregate with CHA is reviewed by considering the compressive strength and workability of fresh concrete and the splitting tensile strength, flexural strength, durability under acid and alkaline media, thermal conductivity, and rapid chloride permeability test of hardened concrete. The results indicate that the partial replacement of fine aggregate with 4% of CHA (CHA04) in concrete provides a positive impact to all the selected performance parameters. The compressive strength, flexural strength, and splitting tensile of the CHA04 mix were 43.4 MPa, 3.7 MPa, and 2.44 MPa, respectively, which were 28.4%, 19.35%, and 1.66%, respectively, greater than normal concrete mix (CHA00). Even the study of acid and alkaline attack on the CHA04 mix showed lesser strength reduction as compared to other mixes. The RCPT showed less chloride permeability, and the thermal conductivity is higher for CHA04, indicating lesser voids compared to other mixes. With the help of this investigation, it can be said that fine aggregate replacement with 4% CHA has the best strength and durability properties compared to regular concrete.

Behavior of Square Footings Reinforced with Glass Fiber Bristles and Biaxial Geogrid

This study investigates the influence of biaxial geogrids on the flexural behavior of square footing foundations reinforced with glass fiber reinforced concrete (GFRC). Experimental research is conducted, involving the testing of five reinforced concrete square footings under area loading until failure. The variables considered are the number of geogrid layers and the percentage of longitudinal reinforcement. Various parameters including deflection, loads at each stage, stiffness, ductility, energy absorption, crack patterns, as well as strains in steel, concrete, and geogrid, are analyzed and compared. The results reveal that incorporating geogrid layers as a reinforcement technique with GFRC significantly enhances the flexural behavior of the footings and improves cracking patterns. The number of geogrid layers used in the footings substantially increases the loads at each stage. Furthermore, an empirical equation is developed to establish a correlation between the moment acting on the footings and the tensile strength of geogrid reinforcement. The empirical evidence demonstrates a substantial improvement in the strength resistance of geogrid-reinforced footings with GFRC, surpassing those reinforced with steel and normal concrete mix. This research contributes valuable insights for the design and construction of earth structures, highlighting the advantages of biaxial geogrids in reinforcing GFRC footings with enhanced flexural performance.

Predicting Strength Properties of High-Performance Concrete Modified with Natural Aggregates and Ferroslag under Varied Curing Conditions

High-performance concrete (HPC) is obtained by inclusion of mineral admixtures like silica fumes and fly ash to the normal concrete. Consumption of natural materials such as sand, natural aggregates, and limestone produces environmental degradation. Similarly, industrial by-products such as fly ash, silica fume, and ferro slag need to be safely disposed of without negatively impacting the environment. The problem being addressed in this study is the need to develop high-performance concrete (HPC) that is durable and environmentally friendly. In recent years, the use of natural aggregates and ferro slag as partial replacements for traditional aggregates has gained attention as a sustainable alternative in the production of concrete. However, there is limited research on the effect of these materials on the mechanical and durability properties of HPC under varied curing conditions. In this current research, high-performance concrete of M60 grade with partial substitution of coarse aggregate with ferro slag aggregate was formed as per the recommendations of the American Concrete Institute with the inclusion of fly ash and silica fume. Natural coarse aggregate was partly substituted by ferro slag aggregate in proportions from 0% to 40%. Partial substitution of cement was made with 15% of fly ash and 10% of silica fumes. Specimens of normal concrete mix (MF0) and modified ferro slag aggregate concrete mix (MF20, MF30, and MF40) were prepared and subjected to acid test, sulphate test, and alternate wet and drying tests to assess the compressive strength of the concrete mixes. Central composite design (CCD) of RSM modelling was adopted to recommend a regression model to forecast the compressive strength of concrete under wetting drying test, acid test, and sulphate attack. Further, natural aggregate, ferro slag, and duration of curing were considered as basic variables to suggest the model. Regression models for response data were evaluated using analysis of variance (ANOVA) and Pareto charts. The results show that the mix MF30 (30% substitution of natural aggregate by ferro slag aggregate) had higher compressive strength. The residual compressive strength at 270 days under alternate wetting and drying, acid attack, and sulphate attack was obtained as 62 MPa, 62.50 MPa, and 66.50 MPa, respectively. Similarly, the percentage loss of weight was obtained as 12.92%, 12.22%, and 6.60% for alternate wetting and drying, acid attack, and sulphate attack, respectively. The findings of the analysis of variance (ANOVA) indicate that the most significant factors influencing the variables C S W D , C S A T , and C S S T are natural aggregate, ferro slag, and curing period. The regression models for C S W D , C S A T , and C S S T are extremely significant, as shown by the ANOVA and Pareto chart analyses.

Comparative Study of Rapid Chloride Penetration Test (RPCT) on Self Compacting Concrete (SCC)

Abstract: To check resistance to chloride ions penetration, we used Electrical resistivity techniques to give an indication of the relative permeability of concrete. The ASTM C 1202 (Standard Test Method for Electrical Indication of concrete’s ability to resist chloride Ion Penetration), more commonly known as the rapid chloride permeability test (RCPT). Self-compacting concrete (SCC) is a very fluid concrete and a homogeneous mixture. In this research work, M40 grade of concrete mixes were made using IS 10262:2019 method. The fresh and harden properties of SCC was taken at the ages of 3,7 and 28 days. After experimental investigation, we can conclude that SCC was more workable than the normal concrete and it did not show any major reduction in compressive strength up to 2% replacement of Super plasticizer. The RCPT is performed on Normal & SCC mix after 28th days and SCC mix showed less values of charges passed than that for the normal concrete mix. Hence, SCC has more resistance to chloride ions penetration.

Properties of concrete replaced with different percentages of recycled aggregates

The main objective of this study is to implement ecological and sustainable principles in the design of concrete mixes by partially replacing normal aggregates with recycled aggregates. Different proportions of recycled coarse aggregates were used to produce normal strength concrete mixes with compressive strength of 40 MPa. The percentages of recycled aggregates used were 20%, 40%, 60%, and 100%. In addition, concrete mixes with 100% normal aggregates were prepared to act as benchmark mixes. The tests conducted to verify the mechanical and physical properties of the concrete mixes were compressive strength tests, slump tests, and water permeability tests. Test results indicated that the workability of concrete was either improved or remained unchanged in the early stages of the concrete life due to the usage of recycled aggregates in different ratios of replacement. In addition, using 20 and 40% recycled aggregates resulted in adequate compressive strength compared to normal concrete. On the other hand, the compressive strength drastically reduced when 60 and 100% recycled aggregates were used compared to that with normal aggregates. Finally, the use of recycled aggregates did not impact the concrete ability to resist water penetration.

Determining the mix design method for normal strength concrete using machine learning

There exist many empirical data-based methods that facilitate the process of concrete mix design. The output of mix design methods are the proportions of concrete constituents that when mixed together produce hardened concrete, taking into account the required strength, workability and durability requirements. Based only on the proportions of the mix, it can be challenging to determine the designing method. Therefore, in this work, computer-generated data was used to train a simple machine learning model to determine the method by which a normal strength concrete mix was designed. The developed machine leaning model only requires knowledge of the mix’s proportions, i.e., the amounts of cement, water, sand, and gravel to accurately determine the method by which the mix was designed. It was found that a simple machine learning model (decision tree) was able to determine the mix design method with high accuracy. Moreover, via principal components analyses, and other similar techniques, it was found that amount of cement is the best predictor of the mix design method. Findings of this work provide a method for determining mix design methods and promote the use of machine learning in the field of civil engineering.

Investigation on Mechanical Properties of Concrete by Partial Replacement with Silica Fume and Foundry Sand with Construction Demolition Waste

New industries come in existence very rapidly. So, that demands of construction industry increase and waste material production also increases with increase of factories like foundry sand from metal factories, silica fume from silicon or alloy factories and construction demolition waste from old buildings destruction. These materials are used either for land filling or dispose in water which creates environmental issue or pollution. Demand of natural resources (fine and coarse aggregate) also increases due to the increase in demand of construction industry; high demand of natural resource also increases cost of construction. These waste materials are not used anywhere but it can be used again for construction purpose that will result in the economic building construction and reduce the environmental issue. In this paper the experimental work done on concrete with partial replacement of silica fume, construction demolition waste and waste foundry sand for using it in construction purpose and the conclusion comes out that when we replace the construction Demolition waste at 15% strength decrease from the normal concrete mix strength after that at 20% it increase from 15% concrete mix and at 25% its strength comes near the strength of normal concrete mix but workability decreases. So we can use this type of material for road construction. By 10% replacement of silica fume strength increase but after 10% it starts decreasing. By replacement of Waste Foundry Sand strength of concrete mix increase from the normal concrete mix up to 15% replacement of Waste Foundry Sand, increase the strength but after that it start decreasing. When we take the combination of the mixes then it comes out near the normal concrete mix strength. So, we can use these materials where we need low workability concrete like for road purpose.

Characterisation of pervious interlocking pavers for durable pavements: a laboratory study

ABSTRACT Pervious concrete is a special type of concrete, achieved by either minimising or excluding the fine aggregates from the normal concrete mix. It is used to lower the problem of local flooding in municipal areas thereby decreasing the burden on municipal drainage system. This investigation was undertaken to examine the strength and durability properties of Pervious Interlocking Pavers (PIP) made with three grades of aggregates with varying fine aggregate proportions of the order of 0%, 10% and 20%. Additionally, the effect of 10% replacement of ordinary Portland cement with silica fume was experimented. The powder to aggregate ratio and water to cement ratio were retained constant at 0.2 and 0.35, respectively. The results showed that utilising 20% of fine aggregates increases the strength and durability properties of pervious interlocking pavers significantly without compromising the permeability limits at 28 days of curing. A substantial development in compressive strength of the order of 15.7% and 35.7% was observed at 10% and 20% substitution of fine aggregate for mixes PC10 and PC20 relative to control mix. Moreover, the partial replacement of silica fume compensates for the strength and durability loss for pervious interlocking pavers made without the inclusion of fine aggregates.

Mechanical properties of pavement quality concrete with aluminium industry waste as a binder

Utilizing industrial marginal materials in the production of concrete makes it economical by reducing the cost of cement and reduces the environmental risk associated with Ordinary Portland Cement (OPC) production. Aluminium Dross (AD) is an industrial by-product from aluminium industry obtained during resmelting of aluminium ore in the furnace at high temperatures. Dumping of this waste in landfill makes it difficult to facilitate large area required and causes nuisance to the surrounding environment. Also, it is required to minimize the use of Ordinary Portland Cement (OPC) due to higher energy consumption involved in its production. AD is pre-treated and tested by Toxicity Characteristic Leaching Procedure (TCLP) to check its leachability. In this study, mechanical properties of concrete along with flexural fatigue behaviour are discussed with respect to partial replacement of AD for OPC. Strength properties of concrete at 15% AD replacement is comparable with that of control concrete. Scanning Electron Microscope (SEM) image of the concrete mix with 15% AD is taken to observe minor voids in comparison with the SEM image of normal concrete mix. Flexural fatigue behaviour is evaluated at varying stress levels and found that the concrete with 15% AD is satisfying the requirements to be used as Pavement Quality Concrete.

Evaluation of environmental disturbance indicator using functional performance and life cycle assessment of ferrochrome waste concrete

This paper reports on environmental disturbance indicators (EDI) using functional performance-based life cycle assessment (LCA) on concrete prepared using waste materials from the ferrochrome industry. The study is made on six concrete mixes with and without waste materials like ferrochrome ash (FCA) and air-cooled ferrochrome slag (ACFS). Lime-activated FCA is used for partial replacement of cement up to 47% and ACFS for total replacement of natural coarse aggregate. The study examines the sustainability of concrete mixes made with ferrochrome waste materials by LCA through the weighting schemes applied to five environmental impacts such as aquatic acidification (AA), carcinogens (CAR), global warming (GW), terrestrial ecotoxicity (TE) and respiratory inorganic (RI). The results of LCA based on the performance in terms of strength and durability indicated benefits in EDI of 46%. The robustness and independence of EDI results were checked through six different weighting schemes and the difference between these varied from 2.87 to 2.40%. The present work also includes the EDI-based study on the best-case and worst-case scenarios that describe the transportation of waste materials from the nearest and farthest plant. The results of such a study indicated that there is a difference of 4–11% between best-case and worst-case transportation scenarios. The contribution of various ingredients of concrete to the environment was checked through contribution analysis using OpenLCA software, where the results showed that cement is the top contributor. Lime and superplasticizer are the 2nd and 3rd contributors. Among the six concrete mixes made with and without ferrochrome waste materials, the normal concrete mix was found most unsustainable. There exists a good relationship between functional unit-based EDI values and scenario-based impact values. Results revealed that the concrete produced using ferrochrome waste materials have low EDI compared to conventional concrete.

Ground palm oil fuel ash and calcined eggshell powder as SiO2–CaO based accelerator in green concrete

Some applications in the construction industry such as precast concrete demand for early strength development. This is normally achieved using accelerator, but most accelerators in the market contain chemicals that adversely affect the environment. This study proposes the incorporation of ground palm oil fuel ash (GPOFA) and eggshell powder (ESP) derived from agriculture and aviculture wastes as bio-accelerator. GPOFA contains high level of silicon dioxide (SiO2) while ESP has high calcium oxide (CaO) content that are responsible for early and later strength development in concrete, respectively. The engineering, chemical and mineral properties of the resultant green concrete were evaluated and discussed. The GPOFA-ESP accelerator had enhanced the mechanical and durability of the concrete when compared to a normal concrete mix. Three types of ESP had been prepared and blended with GPOFA, namely the uncarbonized eggshell powder (UC-ESP), carbonized eggshell powder (C-ESP) and decarbonized eggshell powder (DC-ESP). The combination of 15% GPOFA and 5% DC-ESP resulted in a concrete with the highest average compressive strength, flexural strength and splitting tensile strength consistently over a 90-day curing period. The concrete also had the smoothest surface, highest resistance to chloride and sulphate attack. Thus, this study strongly proposes further research into this GPOFA-ESP combination as concrete accelerator to contribute towards a more sustainable future.

Effect of Expanded Polystyrene Foam Aggregate on Strength and Shrinkage Characteristics of Foamed Concrete

A study has been undertaken to assess some characteristics of foamed concrete, with a given density of 1200 kg/m³, made with expanded polystyrene foam aggregate (EPS). In addition, EPS particles were thermally treated to produce modified expanded polystyrene foam aggregate (MEPS). Thermally treating approach was applied as an effective method to enhance strength of expanded polystyrene foam particles leading to enhance the properties of produced concrete. To investigate the effect of foam presence, normal concrete mix was designed and compared with foamed concrete mix produced with the same mortar content. Properties such as compressive strength, tensile strength and drying shrinkage were assessed. It was found that adding recycled expanded polystyrene foam (EPS) as aggregates helped in slightly enhancing both the strength and shrinkage of foamed concrete. However, thermally treated of EPS to produce MEPS particles resulted in increasing the compressive and tensile strengths by about 68% and 79%, respectively; and reducing the shrinkage by about 52% of that of conventional foamed concrete mix, without EPS. In addition, adding polystyrene aggregates in both states (EPS and MEPS) slightly reduced the spread diameter.

Axial Behavior of FRP Confined Concrete Using Locally Available Low-Cost Wraps

This study investigates the influences of three types of locally available low-cost Fiber Reinforced Polymers (FRP) wraps and two concrete mix designs on the axial behavior of FRP confined concrete. The experimental program comprised four unconfined (control), four glass FRP Matt Strand (GFRP-MS) confined concrete, four glass FRP Rowing (GFRP-R) confined concrete and four carbon FRP (CFRP) confined concrete specimens with a diameter of 150 mm and a height of 300 mm tested under axial compression. The specimens were prepared using two normal strength concrete mix designs, i.e., Mix-A and Mix-B. The experimental results exhibited that an increase in the confined concrete strength per unit cost ratio of a single layer of GFRP-MS was about two times of a single layer of CFRP wrap, whereas the increase in confined concrete strength per unit cost ratio of single layer of GFRP-R was about four times of a single layer of CFRP wrap. GFRP-MS and GFRP-R wraps can exhibit similar confined strengths as CFRP wrap with six and twelve times lower costs, respectively, than CFRP wrap. Mix-B concrete specimens exhibited higher confined concrete strengths but lower confined concrete strain than Mix-A concrete specimens. A database of 140 FRP confined concrete specimens was developed based on a set of specific criteria to develop a design-oriented model to predict the FRP confined concrete strength. The predicted confined concrete strengths matched well with the experimental confined concrete strengths. The two layers of GFRP-R exhibited similar confined concrete strength as CFRP wrap. In addition, GFRP-R exhibited high cement strength index (CSI) and low embodied CO2 index (CI).

A deep learning approach to concrete water-cement ratio prediction

Concrete is a versatile construction material, but the water content can greatly influence its quality. However, using the trials and error method to determine the optimum water for the concrete mix results in poor quality concrete structures, which often end up in landfills as construction wastes, thus threatening environmental safety. This paper develops deep neural networks to predict the required water for a normal concrete mix. Standard data samples obtained from certified/leading laboratories were fed into a deep learning model (multilayers feedforward neural network) to automate the calibration of mixing power of the concrete water content for improved water control accuracy. We randomly split the data into 70%, 15% and 15%, respectively, to train, validate and test the model. The developed DNN model was subjected to relevant statistical metrics and benchmarked against the random forest, gradient boosting machines, and support vector machines. The performance indices obtained by the DNN model have the highest reliability compared to other models for concrete water prediction.

Assessment of Pozzolanic Activity of Ground Scoria Rocks under Low- and High-Pressure (Autoclave) Steam Curing.

Two sources of natural scoria rocks were procured and ground for use in concrete as natural pozzolans (NP1 and NP2). The evaluation of their pozzolanic reactivity is carried out using different techniques and approaches. The primary goal of employing these techniques is to monitor the amount of portlandite (CH=Ca(OH)2) consumed during steam curing at low or high pressure. The pozzolanicity of NP powders is determined either directly by monitoring CH variation or indirectly by compressive strength and microstructure development. Autoclave curing is known to stimulate the pozzolanicity of the inert siliceous and aluminosiliceous materials under its high-pressure steam conditions. Both steam-curing conditions were applied in this investigation. In this study, X-ray diffraction, scanning electron microscope, thermogravimetric, Fourier transform infrared, and isothermal analyzers were used. It is concluded that the nature and types of minerals in SR determine their pozzolanic reactivity as either low-pressure steam-reactive or high-pressure steam-reactive cementitious materials. Due to the nature of their silicate structures, notably single-chain or 3D-framework structures, plagioclase feldspars (albite-anorthite) minerals are high-pressure steam-reactive minerals, whereas pyroxene (enstatite and diopside) minerals are low-pressure steam-reactive minerals. Using high-pressure steam curing, varied replacement levels of up to 60% were achieved in NP1, with a consistent strength activity index (SAI) of 99%, while an SAI of 79% was obtained with NP2. During low-pressure steam curing, NP1 and NP2 consumed around 72 and 80% of portlandite, respectively, demonstrating their relative pozzolanic reactivity. When compared to the control concrete mix, the strength activity indices of NP1, NP2, and class F fly ash in their normal concrete mixes reached 74.3, 82, and 73.7%, respectively, after 56 days of normal curing conditions.

Experimental investigations on mechanical properties of normal and high strength high calcium geopolymer concrete

Alkali activated (Geopolymer) concrete is an excellent and viable alternative to Portland cement based concrete as it can be produced using industrial by-products such as Ground Granulated Blast Furnace Slag (GGBS) and fly ash (source of reactive alumino-silicates) along with less energy craving ingredients such as alkali activators. In this study, slag based geopolymeric concrete mixes of M40 and M80 grade were prepared using GGBS and fly ash in proportion of 70:30 by weight. Geopolymeric binder was activated using combination of Sodium hydroxide and Sodium Silicate. Activator modulus (i.e. SiO2 / Na2O) was maintained as 1 and Na2O was kept as 7% and 8% by weight of total binder respectively for M40 and M80 grade geopolymeric concrete mixes. Both the concrete mixes were evaluated for fresh properties of concrete (slump and air content) along with mechanical properties of hardened concrete. Performance of geopolymeric mixes was compared with two conventional concrete mixes of equivalent grade (i.e. M40 and M80) in terms of aforementioned mechanical properties. Study concludes that slag based geopolymer concrete mixes of a particular strength were developed at significantly lower total binder content in comparison to cementitious binder required for development of conventional Portland cement based concrete of equivalent strength. Early age compressive strength of normal strength geopolymeric concrete mixes is higher in comparison to conventional concrete mix. Modulus of elasticity and Poisson’s ratio of geopolymeric mixes of both normal and high grade are observed to be lower in comparison to their corresponding conventional concrete mixes of equivalent strength.

Physical and Chemical Characterization of Coffee Husk Ash Effect on Partial Replacement of Cement in Concrete Production

Today researchers all over the world are focusing on ways of utilizing either industrial or agricultural wastes as a source of raw materials for the construction industry. This is used to minimize the emission of CO2 during the manufacturing of cement. One of the agricultural waste products is coffee husk which is found in large amounts in Ethiopia. This paper aims to characterize the physical and chemical properties of Coffee Husks Ash (CHA) by using X-ray diffraction (XRD), Scanning electron microscope (SEM), and Fourier Transforms Infrared Spectroscopy (FTIR) tests, and also the experiment were conducted to determine the compressive, split tensile and flexural strength of the material and durability tests were determined. The result have shown that, when the replacement percent further increases, the crystalline material increases, silicate concentration decreases, and also the micro pores or air void are increases, which may lead to decreasing the strength of concrete. In the case of mechanical property of concrete, there has been remarkable increment up to 5% CHA replacement and also strongly satisfied up to 10% replacement, furthermore increasing CHA replacement up to 20% are optimum dosage of normal concrete mix production of C-25 concrete. Finally, water absorption and sulfate attack of partially replaced concrete is shown as an improvement in the durability of concrete.

Pengaruh Penambahan Serat Ijuk Terhadap Kuat Tekan Beton

Concrete is one of the construction materials consisting of a mixture of coarse aggregate and fine aggregate as a filling material, as well as cement and water as a binder. With the addition of fiber as a partial replacement of ceme­nt to obtain a cheaper cost, for simple buildings. With partial replacement of cement with fiber in normal concrete, which aims to determine the effect of partial replacement of cement with fiber against the compressive strength of concrete. By comparing the length variation of fibers which are respectively 4 cm, 6 cm, 8 cm and fibers taken 2% of the weight of cement. Where the calculation analysis (mix desing) using SNI 7656-2012 (procedure for making normal concrete mix plan). Mix design is done in order to determine the proportion of the mixture is done with strong concrete quality planned. The test object is a cylinder with a diameter with a diameter of 15 cm and height of 30 cm. From the results obtained the replacemen of some of the cement with fibers. Where the test results of normal concrete slump of 10 cm, fiber concrete measuring 4 cm by 10 cm, fiber conrete measuring 6 cm byy 9.8 cm and fiber concrete measuring 8 cm by 9.7 cm. And the maximum compressive strength test results obtained decreased, the test value of cylindrical concrete without the addition of fiber of 27.08 MPa, where the compressive strength of concrete by using 2% fibers with a length of 4 cm of 26.70 MPa, concrete fiber 6 cm of 25.94 MPa, and for fiber 8 cm of 24.72 MPa. So that the compressive strength of concrete that occurs decreases from normal concrete without the addition of fibers.