Different Types Of Coarse Aggregate Research Articles

Optimization of the various strengths of concrete made from two different types of coarse aggregates using Scheffe’s model

This research work on the Optimization of the Various Strengths of Concrete Made from Two Different Types of Coarse Aggregates using scheffe’s model. The coarse aggregates (crushed and uncrushed) was obtained from Nkalagu, Ebonyi State. Cement was bought from Kenyatta market, sharp river sand was collected from Nyama River here in Enugu State and water used was gotten from Enugu state water corporation. The practical tests were conducted at Enugu State University of Science and Technology (ESUT) Laboratory, Enugu. Tests that were carried out were series of tests, specific gravity, casting and crushing of the cubes and compressive strength tests were carried out. Natural sand with fineness modulus of 2.27 was used as fine aggregate. Ordinary Portland cement was used as binding material. Mix proportions 1:1:2 with crushed and uncrushed aggregate types were used in the research. The water/cement ratio adopted for the study was 0.59 throughout the experiment. The target mean strength at 28days was 25N/mm2. Twelve concrete cubes (150mm x 150mm x 150mm) were cast for each coarse aggregate type of which three were crushed at each maturing age namely 8, 14, 21, and 28 days from each mix, 12 cubes were cast for each of the two types of coarse aggregate, making a total number of 24 cubes. The concrete cubes are to be casted in laboratory and tested in hydraulic compression testing machine.

Assessment of Post-Installed Anchor Stiffnesses in Uncracked Concrete with Different Types of Coarse Aggregates

This paper investigates the potential influence of different aggregates in the concrete mix design on the concrete cone resistance of different types of anchors as well as the anchor stiffness. In fact, bonded anchors with three different adhesives and mechanical anchors and concrete screws of two types were installed in five different concrete mixes and tested in a standard tensile configuration using pull-out tests with wide support resulting in concrete cone failure. A rigorous analysis of both the initial and secant stiffness values of the different anchor types is carried out in a comparative manner. The results of the experimental program show that the anchor stiffnesses are not influenced by the different aggregates in the concrete mixes, but rather by the type of anchor. Finally, this manuscript provides a narrow range of both initial and secant stiffness values with respect to anchor type only.

Experimental Torsional Capacity of Plain Concrete Beams Made from Crushed Clay Brick and Recycled Brick Concrete as Coarse Aggregate

Concrete was made with four different types of coarse aggregate, i.e., natural stone aggregate concrete (NSAC), crushed virgin clay brick aggregate concrete (VBAC), crushed recycled brick concrete aggregate concrete (RBAC), and crushed recycled stone concrete aggregate concrete (RSAC). Beam specimens prepared from these four types of concrete were subjected to pure torsional moment up to failure. From this experimental procedure, ultimate torque at failure along with twisting angle were observed. From the torque vs. twisting angle curves, torsional stiffness and torsional toughness were also evaluated for these four types of concrete. It was observed that ultimate torque of VBAC and RBAC was 95% and 90% of that of NSAC, respectively. The torsional toughness of VBAC was found to be 68%–72% of that of NSAC. In addition, experimental torques were compared with predictions of torsional strength as per five commonly used models. For VBAC, the ultimate torque prediction made by skew bending theory was found to be the closest to the experimental findings.

STRENGTH OF CONCRETE FOR BASES OF ROAD CLOTHES ON DIFFERENT TYPES OF SECONDARY GRAVEL AND SAND

The task of developing of concrete for the bases of road clothing using secondary concrete aggregates is relevant for an economic and ecological reasons. The properties of concrete were compared with different types of coarse aggregate of 8-16 mm fraction: granite river gravel, secondary crushed stone from recycled reinforced concrete structures, secondary crushed stone from recycled brickwork and ceramic tiles. Three types of sand with a fraction of 0-4 mm were also used: quartz, secondary sand from recycled reinforced concrete structures, secondary sand from recycled brickwork. 2 series of experiments were conducted. During the first series of experiments Portland cement CEM II/B-S 32.5 R and superplasticizer Soudal Soudaplast was used (1% from weight of cement). For the second series of experiments Portland cement CEM II/B-S 42.5 R and superplasticizer Berament HT28 was used (1.2% from weight of cement). The mobility of all mixtures was equal to S1. Concretes with Berament HT28 superplasticizer had a lower W/C ratio of mixture than concretes with similar aggregates composition and Soudal Soudaplast superplasticizer. The use of secondary crushed stone requires an increasing of the W/C ratio of the mixture. The simultaneous use of secondary sand additionally increases W/C. Due to the lower W/C, the concretes of the second series have a higher average density than the similar concretes of the first series of the experiment. Concretes based on granite gravel and quartz sand have the highest average density (2369-2465 kg/m3). When using secondary crushed stone from reinforced concrete structures, the average density decreases by 3-5%. When using secondary crushed stone from brickwork and ceramic tiles – decreases by 8-9%. Concretes based on secondary crushed stone and sand from reinforced concrete structures have a 6-9% lower average density compared to concretes on granite gravel. Concretes based on secondary crushed stone and sand from recycled brickwork and ceramic tiles have the lowest average density – from 2015 to 2061 kg/m3. Due to the use of higher grade cement and a more effective superplasticizer, the strength of the concretes of the second series of the experiment at the age of 3 days was 69-190% higher than the strength of similar concretes of the first series, at the age of 28 days – higher by 67 to 147%. When using quartz sand, concrete based on secondary crushed stone from reinforced concrete structures has the greatest strength. At the age of 3 days up to 17.97 MPa and 30.33 MPa, at the design age (28 days) up to 32.07 and 53.41 MPa for the first and second series, respectively. The lowest strength (about 16 MPa in the first series of experiments and 27 MPa in the second) had concretes using only low-strength secondary aggregates from recycled brickwork and ceramic tiles. In general, all the studied concretes on secondary aggregates were characterized by sufficient strength for their use in the bases of hard road clothes.

Research on the calculation method of concrete compressive strength based on volume content of recycled coarse aggregate and fine aggregate

ABSTRACT In order to study the influence of physical properties and volume content of coarse aggregate on concrete strength, the effective water absorption, apparent density and crushing index of different types of coarse aggregate were tested; the contribution strength coefficient and reinforcement coefficient of coarse and fine aggregate were proposed according to the mechanics of composite materials, the optimal range of the volume content of coarse and fine aggregate was determined, the calculation equation of concrete compressive strength based on the properties of coarse aggregate and the volume content of coarse and fine aggregate was established. The results show that: the effective water absorption of recycled brick aggregate (RBA) is 8.18% and that of natural aggregate (NA) is 0.32%; the apparent density of NA is 2713 kg/m3 and that of RBA is 2100 kg/m3; the crushing index of NA is 18.07% and that of RBA is 30.59%; furthermore, the crushing value of RBA is close to that of cement mortar with water cement ratio of 0.46; NA has a greater range of strengthening the compressive strength of concrete than RBA; when sand cement ratio is between 0.3 and 2.5, both Ks’ and Ks are greater than 1; when sand cement ratio is about 0.5, Ks’ reach the maximum value; when sand cement ratio is about 0.75, Ks reach the maximum value; the calculation equation of concrete compressive strength established in this paper has a good prediction effect, which provides a new idea for the calculation method of concrete compressive strength.

Microstructural analysis of concrete ties with granite and carbonate aggregates after 10 years on Brazil railroads

Some concrete ties have failed prematurely around the world, influencing the structural integrity, service life, and safety of users. Therefore, this study aims to identify the mechanisms of deterioration in concrete ties made with two types of coarse aggregates after ten years of use in Brazilian railroads. The findings will play a crucial role in informing the decision-making process concerning the ongoing presence these elements on the railway track. The study involved a detailed investigation, including petrographic analysis, X-ray diffraction, FTIR/ATR and SEM/EDS on specimens taken from concrete ties. Petrographic analysis confirmed the presence of different types of coarse aggregates in the two concrete groups: one comprising carbonate coarse aggregates and the other featuring granitic aggregates. The presence of ASR gel (boggsite) filling the voids and cracks extending from these aggregates into to the paste was also confirmed. The S1G concrete sample exhibited two types of morphologies of ettringite: ball and massive crystals. The S2C specimens showed incipient carbonation and the presence of brucite, suggesting the occurrence of ACR. Microstructural analysis of both concrete samples showed that concrete degradation occurred through coexisting mechanisms: ASR, DEF, and ACR.

Study on mechanical properties of concrete using different types of coarse aggregates

In the construction industry over the past few decades use of concrete has increased exponentially. This has lead to scarcity of its natural ingredients (Coarse and Fine Aggregates). Hence there is a need to look for other alternatives. This research is aimed at finding suitable alternative to conventional coarse aggregates. The alternatives considered are waste granite marble chips, angular aggregate, demolished aggregate and round aggregate. Eare performed on these so as to ensure the quality of aggregates. M20 Conventional concrete is taken as reference sample and designed as per IS 10262–2009. Coarse aggregate is replaced 100% with each of the above alternatives and these mixes are also designed as per IS 10262–2009. Water cement ratio for all mixes is fixed as 0.50. Standard cubes of size 150x150x150mm were casted for all the concrete mixes, cured and tested for compression test 07, 14 and 28 days age as per IS 516–2002 (Reaffirmed 2018). The compressive strength at 28 days age obtained for reference sample-conventional is 22.35 N/mm2, waste granite chips is 22.04 N/mm2, angular is 21.33 N/mm2, demolished aggregate is 13.41 N/mm2 and round is 13.15 N/mm2 and. It is clear that waste granite aggregate is the best alternative to conventional coarse aggregate.

Effect of Aggregate Types on the Mechanical Properties of Traditional Concrete and Geopolymer Concrete

For the same concrete quality, different types of coarse aggregates may result in different mechanical properties. This paper presents a study on the effect of aggregate types on the mechanical properties of two concretes, namely, geopolymer concrete (GP) and traditional Portland cement (TC) concrete. The mechanical properties were investigated through several large-scale tests. Moreover, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and laser scanning microscope (LSM) images were obtained to study the microstructure of tested mixes. The results revealed that the aggregate type has different effects on the mechanical properties of TC and GP, as they were behaving opposite to quartz and limestone aggregates. Microstructure analysis further confirmed the growth of well-bonded regions between the paste and aggregate in the GP with limestone aggregates, and the formation of several weak interfacial zones in concrete mixtures made with quartz aggregates. It was concluded that the mechanical properties of GP are very sensitive to the stiffness of aggregate, concentrations of stress, and the physical and chemical reactions occurring in the interfacial transition zone which may lead to improved or weakened bond strength between paste and aggregates.

The combined effect of lightweight coarse aggregate and steel fibers on the mechanical properties of concrete

The most evident properties of LWAC by which it is differentiated from normal weight concrete are its lower density and better insulating potential. The aim of this study is to examine the combined effect of lightweight coarse aggregate and steel fibers on concrete’s mechanical properties. In this study, three different types of coarse aggregate (normal weight, crushed clay brick and Attapulgite) with different percentages of steel fiber (0%, 0.5%, and 1%) were used. The results show that replacing normal weight concrete with lightweight concrete leads to a decrease in unit weight, compressive strength, splitting-tensile strength and modulus of elasticity, while water absorption increases. With the increase of steel fiber ratios in the mixtures, the mechanical properties of lightweight concrete improve significantly compared with the control sample with no fiber. When 1% steel fiber is used, the splitting-tensile strength increases by about 115.6% and 55.7% and compressive strength decreases by about 7.4% and 22.2% for crushed clay brick and Attapulgite, respectively, compared with normal weight concrete.

Properties of high performance heavyweight concrete mixtures containing different types of coarse aggregates

Heavyweight concrete having unit weight above 2600 kg/m3 has wide applications that include radiation shielding, offshore, and ballasting of pipelines, etc. In this study, high-performance heavyweight concrete mixtures were developed utilizing industrial byproducts as high-density coarse aggregates. These heavyweight coarse aggregates included steel slag, steel shots, and iron ore. Normal-weight limestone aggregate was also used in the control mixture and for partially replacing the heavyweight aggregates in some of the mixtures. Considering different combinations of coarse aggregates, a total of nineteen concrete mixtures with same water/cement ratio and cement content were prepared and tested for evaluating their performance in terms of different engineering properties. Except the control mixture containing normal-weight limestone aggregate, all eighteen heavyweight concrete mixtures considered in the present work, achieved unit weight (dry density) in the acceptable range of 2600 to 3563 kg/m3. Most of the heavyweight concrete mixtures attained compressive strength either close to or more than 40 MPa, splitting tensile strength and modulus of elasticity above the minimum acceptable limits, drying shrinkage below permissible value, and high resistance against reinforcement corrosion as indicated by their high electrical resistivity and low chloride diffusion coefficient. The experimental data generated under the present work can be utilized to select optimum mixtures of heavyweight concrete satisfying the service conditions.

Effects of Concrete Age on Coefficient of Thermal Expansion of Paving Mixes and Its Significance in Unbonded Overlay Design

Abstract With the advancement in rigid pavement design and advent of AASHTOWare Pavement Mechanistic-Empirical (ME) Design (American Association of State Highway and Transportation Officials, Washington, DC) as the latest design tool, increasing emphasis is being laid on the coefficient of thermal expansion (CTE) of concrete. The CTE affects the performance of rigid pavements in a significant manner, with a higher CTE corresponding to greater curling and resulting in greater pavement distresses. Prior research has conflicting views regarding CTE variation with age, and there has been very little to no research on the effects of CTE on the performance of unbonded concrete overlays (UBCOs). This study is performed to investigate the variation of CTE with concrete age through laboratory testing and further quantify the effects of CTE variation on UBCO design. To facilitate, four concrete paving mixes with different types of coarse aggregates and different mix properties from different districts of New Mexico were collected. The cast specimens from each of the mixes were tested for CTE as per the AASHTO T-336, Coefficient of Thermal Expansion of Hydraulic Cement Concrete, protocol, at the ages of 7, 14, 28, 60, 90, 120, and 180 days, respectively. The test results were analyzed, and it was observed that there is an increase in CTE over the range of 3.49 % to 9.77 %, between 28 days and 180 days. Further analysis was conducted with simulations in Pavement ME Design Version 2.3® that indicated a significantly deteriorated performance of the UBCO with increased CTE. The impact on transverse cracking and joint faulting is the most significant, with up to 13.3 % increase in cracking and up to 19.7 % increase in faulting distress. An unbonded overlay designed with 28 days CTE value may not perform for the design life because of the increase in CTE with age progression.

Comparison of 7 Days, 14 Days & 28 Days Cube Crushing Strength of Thirsty Concrete using Different Types of Coarse Aggregate & Waste Material (Recycled Aggregate) as Coarse Aggregate

Comparison of 7 Days, 14 Days & 28 Days Cube Crushing Strength of Thirsty Concrete using Different Types of Coarse Aggregate & Waste Material (Recycled Aggregate) as Coarse Aggregate

A Review on an Experimental Analysis Work on Strength of Thirsty Concrete with Different Types of Coarse Aggregate

A Review on an Experimental Analysis Work on Strength of Thirsty Concrete with Different Types of Coarse Aggregate

Investigating the Effects of Coarse Aggregate Physical Properties on Strength of C-25 Concrete

The strength of concrete mostly depends on the strength and properties of coarse aggregate since the major volume of concrete was covered by coarse aggregate. The physical properties of coarse aggregates do grossly affect the workability and structural performance of concrete. This study considered the effects of physical properties of coarse aggregate on properties of concrete and the difference in strength of concrete made from four different types of coarse aggregates namely crushed basalt, crushed marble, river graver and surface gravel which were collected from different areas near to Nekemte town. For each types of collected coarse aggregate their physical properties are determined by performing necessary laboratory tests to attain the objective of the study. For proportioning of concrete making materials the ACI concrete mix design was followed. Total of 36 cubes and 12 beam molds were casted for determination of compressive strength flexural strength of C-25 concrete made from the four aggregate samples. The results indicate physical properties and types of coarse aggregate have effects on the strength of concrete. The four coarse aggregate samples have different physical properties and produced concrete having different compressive and flexural strength. Thus, it concludes, the compressive and flexural strength of concrete was greatly influenced by the physical properties and strength of coarse aggregate.

Experimental Investigation of Coarse Aggregates Used for Concrete Production in the Construction of Higher Educational Institution (HEI) Buildings

In the construction industry, an aggregate is an important material used in the production of concrete. The strength of any building component, constructed using concrete will depend on the type and texture of aggregates used. It is on this base that this study analysed two different types of coarse aggregate (crushed granite and washed gravel) used in the production of concrete for higher educational institution (HEI) buildings. The following experimental procedures such as silt content, water absorption, specific gravity, sieve analysis, were conducted on the aggregates sampled to determine the property quality of the aggregates when used with other adhesive. Concrete of ratio 1:2:4 were produced using crushed granite and the washed gravel sampled and its strength was tested with the compressive strength testing machine. The 28 days average compressive test of concrete produced with crushed granite and washed gravel are 23.36 N/mm² and 20.44N/mm² respectively. The study suggests that locally sourced gravel should be washed before use to reduced silt content and impurities in the coarse aggregate. The study concludes that base on the compressive strength result of the study both crushed granite and washed gravel can be used for concrete work in construction work or project, but their selection for usage should be based on expected imposed load.

Effect of various types and sizes of aggregate on self-compacting concrete

Aggregates play important role in concrete; it serves as Structural fillers which are used in concrete production. Aggregate sizes, types and gradation are the most important factor when selecting aggregate. This study examines incorporating different sizes and types of coarse aggregate. Testing rheology and strength of self-compacting concrete mixes at varying sizes and different types of coarse aggregate. The various aggregate sizes used in the Various mixes are 10, 12.5 and 20mm, the types of aggregate used are granite, gravel and ceramic tiles and superplasticizer used is Conplast SP 430 with water cement ratio of 0.45. slump flow test, T50, L-box and V-funnel test were carried out on the various mix to determine the fresh properties of the concrete mix. The mechanical properties (compressive, flexural and split tensile strength test) were conducted on the mixes at different curing age (7, 21 and 28 days). The aggregate size 10mm and granite types had the highest slump flow for the fresh test. It was observed from the mechanical test 10mm and 12.5mm granite size had a higher strength than gravel and ceramic tiles.

Reconstruction of broken Si-O-Si bonds in iron ore tailings (IOTs) in concrete

This paper reports a study on the reconstruction of broken Si-O-Si bonds in iron ore tailings (IOTs) in concrete. Limestone and IOTs were used to investigate the influence of different types of coarse aggregates on the compressive strengths of concrete samples. The differences in interfacial transition zones (ITZs) between aggregate and paste were analyzed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Meanwhile, X-ray diffraction (XRD) and infrared spectroscopy (IR) were used to study microscopic changes in limestone and IOTs powders in a simple alkaline environment that simulated cement. The results show that the compressive strengths of IOTs concrete or paste are higher than those of limestone concrete or paste under identical conditions. The Ca/Si atom ratios in the ITZs of IOTs concrete samples are lower than those of limestone concrete; the diffraction peak of the calcium silicate phase at 2θ = 29.5°, as well as the bands of Si-O bonds shifting to lower wavenumbers, indicates reconstruction of the broken Si-O-Si bonds on the surfaces of IOTs with Ca(OH)2.

Sustainability evaluation of cold-bonded aggregates made from waste materials

Cold-bonded aggregates are technically feasible alternatives to conventional crushed stone aggregates (CSA) in concrete production, but the sustainability of cold-bonded aggregates has not yet been studied. Therefore, this paper suggests a framework for evaluating the sustainability of cold-bonded aggregates. The three pillars of sustainability, namely, social, environmental and economic factors, were used as the main criteria in the evaluation process. Cold-bonded aggregates made from waste materials such as fly ash and quarry dust were used in this study. The sustainability indices of cold-bonded fly ash aggregate (CBFAA) and cold-bonded quarry dust aggregates (CBQDA) were determined and compared with that of CSA. Fourteen sub-criteria were identified for this study. Out of the 14 sub-criteria, six sub-criteria were identified as social factors, another six were identified as environmental factors and two were identified as economic aspect factors. OF the 14 sub-criteria, eleven sub-criteria were qualitative in nature and three were quantitative. A qualitative assessment was conducted via a questionnaire survey of 254 registered practicing engineers. A quantitative evaluation of the embodied energy, lifecycle cost (LCC) and capital cost was performed in this study. The multi-index comprehensive analysis model was used to compute the sustainability indices of different types of coarse aggregates. The sustainable indices of CSA, CBFAA and CBQDA were found to be 0.610, 0.737 and 0.789, respectively. This result indicates that cold-bonded aggregates are sustainable and can be considered for used concrete production. The sensitivity analysis results indicated that the amount of binder and distance to the source of raw materials are important aspects. The framework developed in this study can be used to evaluate other building materials that are relatively new in origin.

The Impact of Marine Water on Different Types of Coarse Aggregate of Geopolymer Concrete

This research studies the impact of different types of coarse aggregate on the behavior of geopolymer concrete based on both fly ash (FA) and ground granulated blast furnace slag (GGBFS) in different marine environments. Aiming to solve the problems caused by the construction and demolition waste and the depletion of natural aggregates, in the present study coarse recycled aggregates is used to produce new green concrete with a fly ash-slag based geopolymer. By this examination, the research seeks to improve the quality and productivity of concrete used in construction and hydraulic projects. For this research, four mixtures containing different types of coarse aggregate in two different water environments were used. The utilized mixtures contained natural aggregate concrete (NAC) such as basalt and crushed marble. Also, recycled coarse aggregate concrete (RAC), which totally replaced natural aggregate, was presented in this paper such as crushed concrete and crushed ceramic. For this study, in the sieve analysis; specific and unit weights, was recorded. Furthermore, the mechanical properties were determined, using a compressive test that was conducted on the 7th, 28th, 56th and 90th days at different water environments; potable water (PW) and sea water (SW). Durability test was also performed for total absorption measurement. Results indicated that geopolymer concrete exhibits better strength in marine environments than in those of potable water. Results also showed that crushed marble (CMA) exhibits higher compressive strength and durability.

Effects of coral, recycled and natural coarse aggregates on the mechanical properties of concrete

The effects of different types of coarse aggregates on mechanical properties of concrete were compared in this paper. Three different coarse aggregates were considered: natural coarse aggregate (NCA), recycled coarse aggregate (RCA) and coral coarse aggregate (CCA). An experimental campaign was developed involving uniaxial compression tests and the use of digital image correlation (DIC) method to obtain the deformation distribution and crack propagation of specimen. The influence of coarse aggregate on deformation development of concrete phases (cement mortar and interface transition zone (ITZ), etc.) was also studied. Test results indicated stress-strain curve (SSC) of concrete using NCA (natural aggregate concrete) was similar to that of concrete adopting RCA (recycled aggregate concrete), while SSC of coral aggregate concrete (concrete using CCA) was different from the others. Compared with coral aggregate concrete (CAC), the failures of natural aggregate concrete (NAC) and recycled aggregate concrete (RAC) were more ductile. But prismatic compressive strength of CAC was higher than other specimens. Coarse aggregate type had obvious influence on the distribution of axial deformation fields of concrete. It indicated that the axial displacements of cement mortar and ITZ were higher than that of NCA before peak point. After mixing different types of coarse aggregates, obvious changes were not found in the displacement distribution of specimen. It was also found that the large strains (axial and transverse) of NAC and RAC mainly concentrated in cement mortar and ITZs before peak stress, however, those of CAC obviously appeared in CCA. Type of coarse aggregate changed the crack propagation of concrete. Compared with NAC and RAC, CAC cracking seldom appeared before peak stress, and cracks drastically expanded to critical size after that. Finally, a normalized analytical expression for different types of concretes was suggested, which could provide a basis for the application of recycled and coral aggregate concretes.