American Concrete Institute Method Research Articles

Experimental study of concrete mixes using crushed and uncrushed coarse aggregates by adopting ACI and DoE methods

AbstractThe main objective of this research is to investigate experimentally the effect of crushed and uncrushed coarse aggregate on the properties of hardened concrete (compressive strength) by adopting the American Concrete Institute (ACI) and the British Department of Environment (DoE) methods. Concrete mixes were designed, concrete cubes and cylinders were prepared and casted by using DoE and ACI respectively. DoE concrete design method considers both types of aggregates; crushed and uncrushed, while the ACI method does not take into account the effect of uncrushed coarse aggregate in design provisions. Then compressive strength tests of concrete samples were determined at ages of 7 and 28 days full curing period. The results obtained show that ACI gave higher values of compressive strength than that obtained by DoE for M30 and M40 except M25, which resulted in lower values than that obtained by DoE for crushed coarse aggregates. The 7-day compressive strength represents 75% of the 28-day compressive strength for ACI method, whereas in DoE reaching up to 73% and 77% for crushed and uncrushed coarse aggregate, respectively.

Comparative Study of M30 and M35 Grades of Concrete Using BIS, ACI, and DOE Methods of Mix Design.

Mix design is a critical process in concrete production that determines the optimal combination of materials to produce concrete with desired properties. In this, we will discuss three commonly used methods for mix design: the American Concrete Institute (ACI) method, the Bureau of Indian Standards (BIS), and the Design of Experiments (DOE) method. The cement, water, fine aggregate, and coarse aggregate ratios needed to produce the desired strength and workability are calculated using the commonly used ACI technique. The ACI technique uses experimental data and historical experience to arrive at an appropriate mix design. The BIS technique, which offers recommendations for the selection of materials, proportions, and testing processes to achieve the specified strength and durability of concrete, is comparable to the ACI method. The DOE technique is a statistical strategy that entails developing a design matrix and doing tests to ascertain the impact of various elements on the characteristics of concrete. This approach makes it possible to evaluate the variables that affect mix design in a more systematic and thorough manner, producing a concrete mix that is more effective and optimized. In conclusion, while the DOE method is a more challenging approach that may result in more effective and optimized mix designs, the ACI and BIS approaches are frequently utilized and offer helpful guidance for mix design. In the end, the strategy used will depend on the particular needs of the project and the resources that are available.

Pemanfaatan Agregat Sungai Aralle Kecamatan Buntu Malangka sebagai Bahan Campuran Beton

Development in Buntu Malangka District is increasingly rapid, especially in the field of development, so the use of concrete becomes the main choice as a building construction. Construction in the field of concrete construction used in the area uses more aggregates derived from rivers. The Aralle River, which is one of the major and closest rivers in the area, is the main location for people to take aggregates, and no previous research has been done on the level of aggregate resistance when used as a concrete mix. The purpose of this study was to find out the aggregate characteristics of the Aralle River and its strength in concrete work. Powerful press plan 20 MPa using the American Concrete Institute method. Cylindrical test object 15 cm diameter 30 cm high for strong testing press 12 pieces and strong pull 3 pieces and beams 60 × 15 cm, strong test bending 3 pieces. Based on the results of the study obtained on the average concrete press strength test at the age of 7, 14, 21, 28 days each amounted to 9,903 MPa, 15,468 MPa, 18,203 MPa, 21,126 MPa. At the age of 28 days obtained strong tensile 2,028 MPa, strong bending 2,756 MPa and Modulus elasticity 21252,778 MPa. Based on the results of the study it can be concluded that the characteristic value and strong testing press at the age of 28 days obtained the value of meeting and achieving the planned quality so that the aggregate is well used in concrete construction.

Comparison between the British and American Methods in Designing Concrete using Local Aggregate in the City of Mosul Preparation

This research included an applied study for the design of concrete mixtures by following the method of the American Concrete Institute (ACl) and the method of the Building Research Center in England (British method) to restriction which of these two methods is more suitable for use and application in the design of concrete mixtures when using local aggregate (gravel and sand taken from the area Badush and Aski Mosul), where job mixes were made using the mixing ratios obtained from these two methods, and a comparative study was made for the properties concrete resulting in the soft state (workability )and the hardened state (compressive resistance), and the results proved the following: A- In general, when discussing the results according to mixing ratios and workability levels, the method of the Building Research Center in England (the British method) gave higher results than the results obtained by the American Concrete Institute method (the American method) when using the above local aggregate whereas results shown increase in (workability) and Compressive strength. This increase amounts to the percentages shown in the table below: Compressive strength (%) Slump test (%) workability 10.48 14.40 Precipitation = 10-8 cm 12.10 21.40 Precipitation = 18-15 cm Table (1-1) B- It is possible to make another comparison, when fixing the proportion of water/cement, it turns out that the method of the Building Research Center in England (the British method) gives higher workability than the method of the American Concrete Institute (the American method) and for the same proportion of cement/ water, the American method gives Higher compressive strength than the British method. C- The building research center method is a more practical and applicable method more than the American Concrete Institute method because it takes the type of cement, the type of aggregate and other properties of the aggregate (especially particle shape) into consideration

The Influence of Rattan Fibre Addition to The Compressive Strength of Normal Concrete

Concrete is high in compressive strength but low in tensile strength and very brittle material. In this study, rattan fibre used as an added material to help eliminate the brittle properties of normal concrete. Variations of fibre used consisted of 0%, 0.5%, 1%, 1.5%, and 2% by weight of cement with mixed planning using the American Concrete Institute method. The compressive strength and stress-strain tests were carried out when the concrete was 28 days old, with a design compressive strength of 25 MPa as many as 15 pieces. The value resulting from testing on normal concrete without the addition of fibres is 24.94 MPa, 0.5% variation of rattan fibres is 23.23 MPa, 1% variation of rattan fibre is 25.3 MPa, 1.5% variation of rattan fibre is 25.85 MPa, 2% variation of rattan fibre is 23.59 MPa. Normal concrete compressive strength test showed an increase in strength at 1.5% rattan fibre and decreased at an additional 2%. The result of stress-strain test in normal concrete without rattan fibre is 0.00125, 0.5% of 0.00254, 1% of 0.00067, 1.5% of 0.00053, 2% of 0.00333. The stress-strain test shows that the addition of rattan fibre can help eliminate the brittle properties that are lacking in normal concrete in general.

Evaluation of conventional and equivalent mortar volume mix design methods for recycled aggregate concrete

The use of recycled aggregate concrete (RAC) is undoubtedly on the increase and further research is required for more appropriate mix design methods. This paper presents the result of investigations into the mix design of RAC. The study examined experimentally two conventional and one unconventional mix design methods. The conventional methods include the absolute volume approach according to the American Concrete Institute (ACI) standard and the Department of Environment (DoE) concrete mix design method given by the British specification. The unconventional method is a new technique dubbed “Equivalent mortar volume (EMV)” method developed to incorporate both fine and coarse recycled aggregates for RAC production. A total of four mixes were designed as follows: (1) natural aggregate concrete regarded as the reference mix using the ACI guide, (2) RAC using the ACI guide, (3) RAC using the DoE guide and (4) blended aggregate concrete using the EMV guide. Fresh concrete properties were tested, and twenty concrete cubes and eighteen cylinders were produced accordingly and tested after curing by water immersion for density, compressive strength, tensile splitting strength and water absorption. The results showed that the EMV mix design method used significantly lesser amount of cement to achieve a RAC of higher strength than those obtained from its comparable conventional methods even with original natural aggregates. This is the first work on mix design of RAC incorporating both coarse and fine crushed concrete aggregates carried out using the EMV method. This research highlights that the ACI and DoE mix design method guides should be reviewed and amended appropriately, before adopting them for RAC mix design.

Design of Normal Concrete Mix Based on Both Building Research Establishment and American Concrete Institute Method of Mix Design

To achieve a defined workability, strength and durability in construction works, concrete mixes are designed and this is done towards the selection and proportioning of constituents to produce a concrete with pre-defined characteristics both in fresh and hardened states. This study assesses the design of normal concrete mix based on the American Concrete Institute and Department Of Environment methods of mix. A characteristic strength of 20 N/mm2 was designed for using the two mix design methods. The concrete components used were tested for specific gravity; moisture content, particle size distribution, aggregate impact value, aggregate crushing value, slump test and compacting factor test and were found suitable. Two sets of concrete cubes (150 x 150 x 150 mm) each were cast using two mix designs. Compressive strengths were evaluated at 7, 14, 21, and 28 days of curing. The 28th day strengths of the two sets of concrete were found to be 30.5 N/mm2 and 29.5 N/mm2 for both DOE and ACI mix design methods which did not exceed the calculated targeted strength.

Análise da viabilidade técnica da incorporação de agregados reciclados em concreto

Os resíduos da construção civil causam grande impacto ambiental, pois são gerados em grande volume e contaminam recursos naturais, porém ele apresenta grande capacidade de reciclagem, possibilitando sua reinserção no ciclo da construção civil, pela substituição dos agregados naturais por reciclados. Este trabalho tem como objetivo, comparar a resistência de concretos com substituição de agregados reciclados nos teores de 15%, 30% e 100%, por meio do ensaio de compressão axial. A execução da pesquisa se dividiu, principalmente, em caracterização física dos agregados, dosagem dos traços de concreto pelo método do American Concrete Institute e o ensaio de compressão axial. A resistência à compressão aos 28 dias do concreto 100% reciclado e do concreto 100% natural se mostraram semelhantes, sendo 30,8 e 32,71 MPa, respectivamente, afirmando que a incorporação de agregados reciclados em novos concretos é viável.

Microstructural and topographic characterization of concrete protected by acrylic paint

Concrete structures must be designed and constructed so as to resist the conditions established in the project design and suffer no deterioration for many years. In highly aggressive environments, in addition to the minimum layer covering the framework, the concrete must receive a protective coating. In this work, the efficiency of acrylic paint as a protective coating, while the concrete was placed in an aggressive environment, was assessed utilizing a profilometric and microstructural characterization. The concrete was dosed using the ACI - American Concrete Institute method. The specimens were prepared with 370 kg.m-3 of cement and the water-binder ratio of 0.50 corresponds to the value established in NBR6118¹ types for concrete subjected to highly aggressive environments. With the use of profilometry, 3D topographical images and surface roughness parameters were generated, which allowed for the identification of the degradation process and the minimization of the effect of this attack on concrete that had received surface protection. The topographic roughness parameters, as well as the images and chemical components identified using SEM/EDS, made it possible to identify the process of deterioration of the concrete under acid attack and to minimize such effect in the coated concrete. The methodology adopted demonstrates that the application of acrylic paint as a protective coating for concrete in an aggressive environment minimizes its surface degradation and increases its durability.

Fire Resistance of Four-Face Heated Reinforced Concrete Columns

Until now, the determination of fire resistance of reinforced concrete (RC) columns has essentially been based on tabulated data. Clearly, a more scientific approach based on an understanding of the fundamental behavior of columns in fire is timely and will be useful to structural engineers. This paper develops a simple and rational method to predict the fire resistance of RC columns subjected to four-face heating. The effects of elevated temperature on material deterioration with regard to the strength and stability of the columns are quantified. Both uniaxial and biaxial bending of columns is considered. The computer code \ISAFIR\N, developed at the University of Liege, was used to analyze reported experimental results and to simulate the deformation response. The approach comprises three steps. The first step is to determine the respective strength reduction factors of concrete and steel and the modulus of elasticity at elevated temperature on the basis of numerical simulations using \ISAFIR\N. The second step is to calculate the balanced failure point of the column, so as to determine whether the applied load eccentricity is small or large. The third step is to determine the failure load by a trial and error process. This method can be regarded as an extension of the existing American Concrete Institute method for ultimate strength predictions of RC columns at ambient temperature.

Flexural Strength of Reinforced Polymer Concrete Made with Recycled Plastic Waste

Investigators evaluated the flexural behavior and strength prediction of steel-reinforced polymer concrete (PC) using unsaturated polyester resins based on recycled polyethylene terephthalate (PET) plastic waste. Most beams were singly reinforced with steel bars in the tensile zone. Some beams used double reinforcement with steel bars in the tensile and compression zones. Test results revealed that very good flexural strength can be obtained with reinforced PC using unsaturated polyester resins based on recycled PET. Researchers first investigated prediction of the ultimate flexural strength of steel-reinforced PC beams by using the traditional American Concrete Institute (ACI) approach developed specifically for steel-reinforced portland cement concrete. The findings of this analysis revealed that the ACI method produces conservative results when applied to reinforced PC. An alternative method of predicting the ultimate flexural strength of PC is introduced using multiple regression analysis on the experimental data.

Knowledge‐Based Expert System for Concrete Mix Design

In the United States, the American Concrete Institute method (ACI 211) is the most widely used concrete mix design. However, ACI 211 does not consider all factors regarding concrete mix design. The acceptance of a freshly mixed concrete depends on concrete quality control test results. If the results indicate that the concrete does not meet the specification, mix design adjustment must be made. Concrete mix design and adjustment are somewhat complicated and time‐consuming tasks that are performed best by experienced persons. In this project, a rule‐based expert system was developed to assist the user in concrete mix design, including the necessary adjustments to the design. The expert system can handle mix designs for normal‐weight concrete, normal‐weight‐mass concrete, normal‐weight no‐slump concrete, heavyweight concrete, and lightweight concrete. Besides workability, consistency, strength, durability, and density, the expert system considers other criteria such as admixtures, transportation, and air te...