American Concrete Institute Research Articles

Utilization of Rice Field Conch Shells as a partial substitution of Cement and Fine Aggregate for Split Tensile Strength of Concrete

Aceh is one of the provinces in Indonesia which has a very large area of rice field production. However, there are many pests that hinder agriculture in Indonesia. One of them is the rice field conch shells which has the potential to cause very high losses to the rice crop harvest. The aim of this research was to determine the ratio of the split tensile strength of concrete using rice field conch shells as a partial replacement for cement and fine sand against normal concrete by 0%, 5%, 10%, and 15%. In addition, it was also seen the effect of immersing concrete specimens using rice field conch shells substitution in tap water and water collected from paddy's farm. This study used the ACI (American Concrete Institute) 211.1-91 and ASTM (American Society for Testing and Materials) methods. The specimens consisted of cylinders with dimensions of 15 cm x 30 cm, totaling 40 specimens with a design concrete compressive strength of 17.00 MPa. The curing of the specimens was carried out using tap water and water collected from paddy's farm for 28 days in the soaking tub. The results showed that 5% substitution of rice field conch shells in cement and fine sand using the tap water immersion method showed a 3% increase in the tensile strength of concrete in comparison with normal concrete. Meanwhile, immersion using the water collected from paddy’s farm method showed a decrease in the value of the split tensile strength of the concrete.

Review of Residual Mechanical Properties of Concrete Mixed with Different Admixtures at High Temperatures

In this study, we analyzed results reported in existing literature to examine the residual mechanical properties of concrete mixed with different admixtures. Ground granulated blast furnace slag (GGBFS), fly ash (FA), and metakaolin (MK) were selected as admixtures for analysis, and data reporting the residual compressive strength of concrete with different admixtures at high temperatures were analyzed. Then, with reference to the ordinary Portland cement (OPC) using 100% cement, prediction formulas for the residual mechanical properties of concrete were derived for each selected admixture, and the resulting values were compared with the values of codes used in international concrete specifications. The residual mechanical properties of concrete showed different results depending on the admixtures used, and the concrete mixed with MK showed a higher compressive strength than OPC at room temperature compared with the values of the existing codes. With increasing temperature of concrete exposure, the trend of compressive strength showed convergence to the values of the existing codes. At room temperature, concrete mixed with GGBFS or FA showed a trend of similar or lower compressive strength compared with that of the existing codes; however, with increasing temperature, the residual compressive strength exceeded that of American Concrete Institute (ACI) and CEN codes. Thus, at room temperature, concrete mixed with MK had excellent compressive strength, but with increasing temperature, concrete mixed with FA or GGBFS was observed to exhibit superior residual mechanical properties.

Fuzzy Logic, Neural Network, and Adaptive Neuro-Fuzzy Inference System in Delegation of Standard Concrete Beam Calculations

Machine learning (ML) has been proven effective in various scientific and industrial domains. Nevertheless, its practical application in the construction industry requires further investigation. Leveraging ML capabilities conserves human resources, reduces errors, and speeds up computation and interpretation tasks. The efficacy of ML algorithms depends on factors like ability, result accuracy, analysis cost, and sensitivity to parameter count and available data volume. This study explores the potential of using ML to delegate structural calculation processes, which is an aspect with limited attention. Concrete beam section calculations based on the American Concrete Institute (ACI) standards were chosen as a case study to assess ML’s capacity to emulate a structural designer’s role. Initially, manual design steps and standard considerations for a concrete beam section were parametrically coded in MATLAB. Validation against structural design references ensured code accuracy in calculating shear and bending capacities. The parametric results served as initial data (lookup table) for training ML operators. Various ML techniques, including fuzzy logic (FL), neural network (NN), and adaptive neuro-fuzzy inference system (ANFIS), were coded in MATLAB. A comparative analysis of the three ML operators assessed their performance in replacing standard calculations. Parametric examples illustrated each operator’s precision in delegation compared to direct calculations. The study also explored the impact of the number of parameters and lookup table size on the accuracy of each ML operator. The findings revealed that while all three operators could delegate standard calculations, their precision varied. Notably, when the lookup table was optimal, ANFIS operators demonstrated the ability to represent standard calculations with varying parameter counts and high precision. Focused on beam calculations, this study provides insights into ML operator performance. The outcomes, including selecting the most capable operator and their sensitivity to parameters and lookup table size, offer valuable guidance for researchers interpreting experimental and numerical analysis results.

Advancing seismic resilience: Performance-based assessment of mid-rise and high-rise engineered cementitious composite (ECC) Buildings

Engineering Cementitious Composites (ECC) have received wide attention in recent years due to their enhanced mechanical properties and ductility. These properties offer an opportunity to design structures with significantly improved seismic performance having a low-damage and ductile response. However, existing research studies primarily focus on the performance of ECC at material and member scales, resulting in a knowledge gap regarding its response at the structural level. This study examines the system-level seismic response of buildings designed using ECC and compares their performance with those having conventional reinforced concrete (RC) members. For this purpose, two RC shear wall buildings (7-story and 24-story) were selected as a case study, and their elements were separately designed (for the combined gravity and lateral loads) as RC and ECC elements using the guidelines recommended by the Japan Society of Civil Engineering (JSCE) and ACI (American Concrete Institute)−318–19. The design results show that the requirement of longitudinal steel is reduced by a maximum of 24% in ECC flexural members and by 15% in compression members, in addition to a significant reduction in the required transverse reinforcement as compared to the corresponding RC members. Similarly, owing to improved tensile behavior, the ECC members also exhibited a higher shear capacity than RC members. The detailed nonlinear finite element models of the case study buildings (for both the design cases i.e., ECC and RC) were subjected to monotonic and reversed-cyclic pushover analysis, and nonlinear time history analyses (NLTHA) under a set of selected ground motions. It was observed that ECC structures exhibited significantly improved lateral capacity, revered-cyclic response, and overall seismic performance as compared to the corresponding RC structures. These results demonstrate that ECC can be effectively used to design various members for improved seismic performance of buildings.

Mechanical and Microstructural Properties of Bamboo Fiber-Reinforced Concrete Containing a Blend of Waste Marble Powder and Waste Glass Powder

Using blended supplementary cementitious materials in the production of concrete has a contribution to make in reducing cement consumption, as well as having a negative environmental impact. The main objective of this study was to investigate the mechanical and microstructural properties of bamboo fiber-reinforced concrete containing a blend of waste marble powder (WMP) and waste glass powder (WGP) as a partial replacement for cement. To achieve these objectives, the physical and chemical properties of concrete ingredients were studied. The design mix was done as per the American Concrete Institute (ACI) mixing procedure by using 5%, 10%, 15%, and 20% blended WMP and WGP as a replacement for cement and 0.75% bamboo fiber as an addition. The mechanical tests were conducted after samples were cured for 7 and 28 days in water. The microstructural properties of the hardened concrete from three different mixes were also determined for the 28-day cured specimens. The study result indicated improvement in compressive strength, shear stress, and bond stress at M2 (10%), whereas maximum splitting tensile strength was achieved at M1 (5%). Moreover, scanning electron microscopy (SEM) showed a denser microstructure, whereas X-ray diffraction (XRD) illustrated portlandite, calcium aluminum silicate, quartz, and calcium silicate hydrate as common phases of the concrete structure. Eventually, the experimental finding implied that using a 10% blend of WMP and WGP as a partial replacement for cement and 0.75% bamboo fiber improves fresh and hardened concrete properties.

Effect of recycled crushed glass and recycled coarse aggregate on the properties of self-compacting concrete

This research was developed to use recycled coarse aggregate (RCA) and recycled crushed glass (RCG) to produce self-compacting concrete (SCC) mixtures. Natural coarse aggregate (NCA) was replaced by RCA from 0% to 100%, and natural fine aggregate (NFA) was replaced by RCG from 0% to 20%. Slump flow with T500 time, L-box, and V-funnel tests were done to ascertain the workability properties of SCC mixtures. The mechanical properties studied were compressive, flexural, and splitting tensile strength at 28 and 56 days. Ultrasonic pulse velocities (UPV) were also measured for the SCC mixtures at 28 and 56 days. Ten shear-critical beams with different shear span-to-depth (a/d) ratios were also cast and tested under 4-point bending. Cracking load, failure load, load-midspan deflection curves, and deflection corresponding to ultimate load were observed. The recommendations of the American Concrete Institute (ACI 318–14 and ACI 318–19), Eurocode (EC2), and Japanese Society of Civil Engineers (JSCE) for shear design were also evaluated on a database of 222 beams cast with SCC and recycled aggregate concrete (RAC) along with the beams tested in the presented study. Results indicate that the workability and mechanical properties were reduced when the replacement level of RCA was increased. The use of RCG as a replacement for NFA enhanced the workability properties and mechanical properties at the age of 56 days. The replacement of NCA with RCA slightly reduced the shear capacity and stiffness of the RC beams. However, the shear capacity and stiffness of RC beams improved when NFA was replaced with RCG. The design provisions of ACI 318–19 yielded accurate estimates of shear capacity compared to JCSE, EC 2, and ACI 318–14.

Minimum Cost Design for Rectangular Isolated Footings Taking into Account That the Column Is Located in Any Part of the Footing

This work presents a new model for obtaining the cheapest design for a rectangular isolated footing, taking into account that the column is located in any part of the footing. The methodology is developed by integration to obtain the moments, bending shear and punching shear according to the American Concrete Institute ACI 318-14. This document presents the simplified and precise equations of the four moments, four bending shears and one punching shear acting on the footing. Some designs have been developed by the trial and error method to determine the footing dimensions, and later the thickness and steel area of the footing are obtained. Some authors present the minimum cost design for a rectangular isolated footing taking into account that the column is located in the center of gravity of the footing, and other authors present very complex algorithms. Numerical examples are presented to obtain the minimum cost design of rectangular isolated footings under biaxial bending, and some results are compared with those of other authors considering the same conditions. The new model presents a smaller contact area with the soil and a lower design cost than those presented by other authors.

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.

Flexural–shear deformation theory (FSDT) for modeling of mechanical responses of RC beams strengthened in shear with ETS-FRP bars

The flexural–shear deformation theory (FSDT) approach for simulating the shear behavior of reinforced concrete (RC) beams strengthened in shear with embedded-through section fiber-reinforced polymer (ETS-FRP) bars is developed in this study. The key feature of the FSDT approach is to mix both flexural and shear deformation parameters constituted in the beam into an algorithm, which is able to simplify the analysis and shorten the computation time. Most of the formulations adopted in the model are built on the basis of mechanics by applying a few common theories involved in stress and strain fields. Particularly, to couple the participation of the ETS-FRP strengthening system into the developed FSDT, the newly developed bonding-based mechanism between the ETS-FRP bar and concrete is used. The calculation outcome produces the vertical strain (εv), which is the main parameter used to determine the resistance of shear reinforcement. The shear contribution of concrete is derived via the concrete principal tensile strain (ε1). Then, the minimized discrepancy between shear forces induced by flexural (VT) and shear actions (Vtotal) is the condition for termination of the calculation. Through the broad corroboration of the developed model to the experimental data with respect to structural responses, excellent agreement and high accuracy are found. To offer prospects for the design practice of ETS-strengthened beams, a parametric study on the effects of important design variables is implemented against the results assessed by a guideline released by the American Concrete Institute (ACI). Consequently, the proposed FSDT approach provides more insight into the responses of ETS-strengthened beams than the ACI guideline, which is helpful for practitioners.

Flexural behavior of precast lightweight aggregate concrete insulation panels

This study examined the effect of different panel-to-base connection techniques on the flexural behavior of precast lightweight aggregate concrete (PLC) panels with an embedded honeycomb cardboard for lighter weight and better insulation performance. Eight full-size PLC insulation panels were prepared with test parameters including panel-to-base connection techniques, the compressive strength of concrete (fc′), and continuity of span. All panel specimens were tested under symmetrical two-point top loadings in each span. The test results revealed that the flexural design process specified in the code American Concrete Institute 318-19 commonly underestimated the flexural cracking and moment capacity of the PLC specimens. The PLC insulation panel specimens with an fc′ exceeding 13 MPa could be classified into grade 1 as specified in the code KS F 4736, indicating a good flexural resistance. For conservative flexural design of PLC insulation panels, the use of the conventional spliced connection and modified spliced sleeve connection could be considered as a fixed end, whereas the use of screw-bolt-and-spring connections could be considered as a hinged end. The displacement ductility ratios of PLC insulation panels with an fc′ of 24.5 MPa were approximately 1.2 times higher than those of the counterpart PLC insulation panels with an fc′ of 13 MPa, because more severe cracks along the insulation materials were observed in the specimens with lower fc′ values.

Limestone powder, calcined clay and slag as quaternary blended cement used for green concrete production

Cement is among the most widely used building materials in recent years. In addition, the accumulation of massive waste has impacted the city's appearance. As a result, there was a need to reduce waste by using by-products from industrial waste to replace cement and reduce greenhouse emissions to produce mortar or concrete green that has good performance, environmentally and sustainably. This research study aims to design green concrete with the highest feasible replacement level with different cement content that satisfies fresh and mechanical characteristics used for structural application and eliminate negative environmental impacts simultaneously. The empirical work was conducted by preparing 12 blends to produce green concrete by substituting cement with three ratios of various by 30% (10% LMP +10% SS + 10% CC), 40% (10% LMP +10% SS + 20% CC), and 50%(10% LMP +15% SS + 25% CC) with three binder contents (355 kg/m3, 400 kg/m3, and 460 kg/m3). The mix design was carried out according to the American Concrete Institute (ACI) Code. Then environmental influences of green concrete blends were calculated by evaluating the declines in carbon dioxide (CO2) emissions. The results showed that adding limestone powder (LMP),calcined clay (CC), and steel slag (SS) as partial cement replacement decreased the slump properties of fresh concrete, so an increased dosage of superplasticizer (SP) in the fresh properties is needed. Green concrete containing quaternary cement by 30%, 40%, and 50% with SP dosage certain gave higher compressive, flexural, and splitting strength values at 90 days compared to normal concrete. However, UPV values indicate that all green concrete is of suitable quality. While water absorption has slightly increased in quaternary cement containing 50% for binder content 355, 400, and 460 kg/m3 increased by 4.2%, 2.7%, and 2.1%, respectively, compared with plain concrete. The evaluated reduction of carbon dioxide emissions study indicated that the green concrete, when increased in cement replacement percentages by up to 50% for binder content 355, 400, and 460 kg/m3 reduced CO2 emissions by 35.9%, 36.4%, and 37.1%, respectively. As a result, adopting the idea of green concrete is a promising strategy for reducing carbon dioxide emissions and conserving natural resources.

Development of High-Performance Fly-Ash-Based Controlled Low-Strength Materials for Backfilling in Metropolitan Cities

Controlled low-strength materials (CLSMs) have been developed using various byproducts for backfilling or void-filling around pipelines or culvert boxes. However, these CLSMs have encountered issues related to their inadequate placement around underground facilities, despite satisfying the performance requirements, especially flowability, recommended by the American Concrete Institute (ACI) 229 committee. In this study, a new CLSM is developed to ensure a significantly higher flowability, lower segregation, and faster installation compared with previously developed CLSMs. This is achieved through a series of laboratory tests. To enhance the flowability and prevent segregation, a calcium-sulfoaluminate-based binder and fly ash are used in combination with two types of additives. The measured flowability of the new CLSM is 700 mm, while its compressive strength and bleeding satisfy the general criteria specified by the ACI 229R-13. In addition, the performance of the developed CLSM is compared with that of predeveloped CLSMs. The new CLSM was not only shown to exhibit the highest flowability, but also to satisfy the specified requirements for compressive strength and bleeding. Overall, it is anticipated that the developed CLSM can significantly reduce the costs related to the disposal of old pavements, the installation of new pavements, and other construction expenses compared to the costs related to the conventional method, even though the expenses for the backfill materials could increase due to the higher production costs of CLSMs than soil. In addition, there is a need to investigate its field applicability in order to evaluate the precise costs, maintenance, and long-term stabilities after installation.

Assessment of concrete shear resistance of lightweight SCC beams containing scoria aggregates

Lightweight self-consolidating concrete (LWSCC) has become a construction material that combines the benefits of lightweight concrete (LWC) and self-consolidating concrete (SCC). However, this combination may affect the shear resistance of structural members made with such concrete. This paper evaluates the shear resistance and performance of LWSCC beams. Eight full-scale beams without stirrups were fabricated and tested to failure. Seven beams were constructed using LWSCC and one was cast using normalweight self-consolidating concrete (NWSCC). Natural lightweight coarse and fine scoria aggregates were used in preparing the concrete mix. The beams were tested over a simply supported span in a two-point loading configuration. The test parameters comprised the type of aggregates, the reinforcement ratio of longitudinal steel bars, the shear span-to-depth ratio, and the depth of the beam. The experimental results showed that employing scoria aggregates in the mix resulted in beams with a reduced self-weight, where the obtained unit weight of LWSCC was 1800 kg/m3. Compared to the beam with NWSCC, the counterpart beam with LWSCC showed 25% lower shear strength. Additionally, the LWSCC beam experienced a reduction of 20% in the flexural cracking load while the beam showed a larger number of cracks at failure. The shear strength of the beams was predicted using the relevant shear design provisions of the American Concrete Institute building code ACI 318, the Canadian standard CSA-A23.3, and Eurocode 2. The ACI 318 method provided more reliable and conservative estimates for the shear capacity of the tested beams.

Parametric investigation of continuous beams strengthened with near surface mounted FRP bars

This study evaluates the near surface mounted fiber-reinforced polymer (FRP) reinforcement technique for strengthening continuous reinforced concrete beams. A three-dimensional finite element model was developed and validated with a recent experimental study. The model incorporates robust features, including concrete nonlinear behavior, debonding and slipping of FRP bars, and various failures. It was able to capture the ultimate load (Pu) with maximum deviation of 7%, beam’s load–deflection curves, load–strain responses in rebar and concrete, and various failure modes. A parametric study was conducted and showed that failure mode changes from concrete shear to FRP bar debonding at concrete compressive strength fc’of 20–30 MPa, with a 26–52% increase in Pu relative to the un-strengthened beam. Varying the hogging/sagging FRP reinforcement ratio (ρh/ρs) from zero to 2.0 results in a 39% increase in Pu and a change of failure mode. A value of 1.5 is recommended for ρh/ρs. Also, the synergistic effects of NSM FRP and internal steel reinforcements were studied. An FRP bar length in the hogging and sagging zones of 80% the beam span was found to be sufficient to mitigate debonding and thus is recommended. Pu did not vary significantly with the span ratio for two-span continuous beams. A design expression for the debonding strain in FRP bars based on the American Concrete Institute design guide was assessed and a further refined model is developed.

Engineering software development for strengthening concrete structures using fiber-reinforced polymers

In this study, engineering software for the calculations of the strengthening applications of reinforced concrete (RC) load-bearing elements with Fiber Reinforced Polymer (FRP) composite materials is developed. This software is developed to increase the axial compression strength and ductility capacity of columns and improve the shear capacity of beams using FRP material according to provisions of the Turkısh Building Earthquake Code 2018 (TBEC-2018). In addition, this software offers designers the opportunity to perform calculations to increase the bending moment capacity of beams using FRP composite material, according to the American Concrete Institute 440-2R.17 (ACI 440-2R.17). Algorithms to be used to increase the capacities of RC load-bearing elements with FRP composite materials are formed according to the provisions of the mentioned codes. Then, computer and web-based engineering software with different coding languages are developed depending on these algorithms.

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.

Investigating the Effects of Concrete Mix Design on the Environmental Impacts of Reinforced Concrete Structures

This study examines the impact of mix design parameters on the environmental effects of producing concrete and reinforced concrete buildings by conducting a life cycle assessment (LCA) and carbon footprint analysis (CFA). The study is limited to the cradle-to-gate phase, including the extraction and production of raw materials for concrete production, as well as concrete and rebar production, material transportation, and delivery to the construction site for reinforced concrete structures. Three concrete mix designs based on the American Concrete Institute (ACI) 211-09 standard, with compressive strengths of 20, 30, and 40 MPa, were analyzed. The results indicate that cement was the primary contributor to environmental impacts, accounting for approximately 90% of the carbon footprint. Sand, gravel, and admixtures followed cement in their impact on LCA results. Water usage in concrete production had a negligible effect on LCA indicators. Moreover, to determine how mix design parameters impact the carbon footprint of reinforced concrete buildings, three four-story structures were designed. The results show that in reinforced concrete buildings, concrete was a significant contributor to environmental impacts, accounting for over 50% of all indicators in the IMPACT 2002+ and CML baseline 2000 methods, except for resources and acidification. The study underscores the importance of considering mix design parameters in reducing the carbon footprint of reinforced concrete buildings and provides valuable insights into their environmental impacts. The findings indicate that cement is the main driver of environmental impacts in both assessment methods, accounting for around 90% of the carbon footprint. Additionally, concrete plays a substantial role in environmental effects, contributing to over 50% of all indicators measured in the methods used for evaluating environmental impacts.

Pengaruh Serat Ban Bekas dan Abu Batu Bara Terhadap Kuat Tarik Beton

In today's modern era, technological developments are needed to increase development in all fields. The manufacture of concrete can use partial cement substitution materials through the use of industrial by-products such as fly ash and fiber waste from used tires. The benefit of this research is to develop knowledge about concrete technology. The method used in this research is the ACI 211.1-91 (American Concrete Institute) and ASTM (American Society for Testing and Materials) methods with variations in the addition of used tire fiber by 0%, 5%, 10%, 15%, and 5% addition of fly ash from the weight of cement in each variation. The test object used is a cylinder with dimensions of 15 cm x 30 cm with a total of 20 test objects, the planned concrete quality is 17.00 MPa. The tensile strength of concrete test was carried out at the age of 28 days. The results of this study are that concrete with a variation of 0% produces a tensile strength of 2.32 MPa; while the tensile strength with variations of 5%, 10% and 15% were 2.71 MPa, 2.50 MPa and 2.41 MPa. The tensile strength of concrete using tire fiber waste and fly ash increases compared to normal concrete.

A comparative study on analysis and design of R. C. C elevated water tank using different country codes

Around the world, elevated reinforced concrete tanks are most frequently utilized in water dispersal systems for cities and towns. Elevated RCC water tanks come in a variety of designs, including rectangular, cylindrical, conical, and Intze. Because the conical bottom's inward radial push balances the spherical bunny's outward radial thrust, Intze tanks are the most sought-used of them all. Elevated Intze water tanks receive little guidance, despite the fact that the majority of design regulations include standards for rectangular and cylindrical tanks. Using the Ethiopian Building Code of Standards (EBCS 1995), the American Concrete Institute (ACI 350), the Euro code (EN 2004), and the Indian Standard codes (IS 3370), an elevated Intze water tank has been assessed and designed in this paper. The amount of concrete and reinforcement used in each code has also been compared. These constructions are particularly vulnerable to lateral loads brought on by wind and earthquakes because they have a big mass concentrated at the apex of a flimsy hold up framework. A variety of factors were taken into account when performing the design, including the impact of capacity, staging height, terrain type, and wind zone. The hoop stress and meridional thrust at diverse Intze tank parts are determined via membrane simulation analysis.

Experimental studies on mechanical and durability properties of high performance concrete with partial replacement of fine aggregate with crushed Quartzite and binding material by fly ash and silica fume

The high performances concrete’s demand growing day by day due to its mechanical properties like compressive strength and it’s durability characteristics therefore the Research on high performance concrete on its verge. The availability of natural fine aggregates are diminishing day by day there by it is the time to search for alternative. Many researches are using utilizing industrial waste in High performance Concrete. In the present study, M60 grade of the concrete was used and designed as per the mix design standards of American Concrete Institute (ACI, 234R-96). The mechanical properties of HPC, such as compressive strength, split tensile strength, and modulus of elasticity, as well as durability properties, such as acid resistance test, sulphate resistance test, chloride resistance test, ultrasonic pulse velocity test, and alternate wet and dry test, were determined using specimens of regular concrete mix and modified Crushed Quartzite concrete mixes. According to the experimental findings, HPC has good mechanical and durability features when 30% crushed quartzite is substituted for fine aggregate, and the amount of binder is determined by the compressive strength of concrete when varied amounts of fly ash and silica fume are used. Optimization of admixture arrived as Fly ash 15% and silica fume 10% to the weight of cement content.