Fine Aggregate Content Research Articles

Engineering performance of high-content MgO-Alkali-activated slag mortar incorporating fine recycled concrete aggregate and fly ash

This research investigated the effects of recycled fine aggregate (RFA) and fly ash (FA) content on the strength development and engineering properties of alkali-activated slag–MgO (AASM) mortar. Various mortar specimens in which natural sand was replaced by RFA in five ratios (0:100, 25:75, 50:50, 75:25, and 100:0) and 0%, 15%, 30%, and 45% of the slag content was replaced by FA were prepared. Finally, the MgO content was fixed at a constant 7.5% of slag and FA by weight. These mixtures were activated using a solution of sodium hydroxide and sodium silicate. Strength and engineering properties, including flowability, unit weight, water absorption, ultrasonic pulse velocity (UPV), electrical surface resistivity (ESR), and rapid chloride penetration test (RCPT), were evaluated for all of the mortar samples throughout 56 days of curing time. The findings demonstrate that RFA and FA contents significantly affected the properties of mortar specimens, with RFA negatively influencing these properties and the 15% FA content specimen showing the most significant improved strength and engineering properties. Moreover, all of the AASM mortar mixtures exhibited good strength and high durability, with high UPV and ESR values as well as low-RCPT results.

Use of numerical method for optimization of granulometric curves in eco-efficient concrete

Concrete is the most used construction material and thus, being the cement a significant part of this material, it is also widely used around the world. Cement production is responsible for more than 5% of global CO2 emissions, which has been continuously increasing. A solution to reduce the cement content in concretes without loss of performance is thorough the particle packing optimization. This work uses practical numerical simulations through linear programming and the modified Andreasen & Andersen model to reduce the void content of aggregate mixtures and produce concretes with superior and intermediate packing levels. A broad range of distribution modulus “q” values were tested. Deviations between the particle size distribution (PSD) curves were calculated in each step of the process. In this study, mixtures with the smallest deviations – experimental PSD curves closer to the mathematical packing model – did not present the lowest void contents. The distribution modulus “q” directly affects the fine aggregate content in the mixtures: lower q values favors higher fine aggregate contents. For concrete granular skeletons composed by sand and gravel, there is a q value below which sand is the top deviation contributor and above which gravel is the top deviation contributor. Moreover, there is a limit to the distribution modulus after which the void content of aggregate skeletons tends to increase. In this study, that was 0.30. Concretes with superior packing (S concrete) and with the lowest distribution factor (q = 0.25) showed better performance in relation to the other studied concretes, with a higher compressive strength at 91 days and with a binder intensity around 6 at 28 days and below 5 at 91 days.

Effect of dumped iron ore tailing waste as fine aggregate with steel and basalt fibre in improving the performance of concrete

The present study investigates the effects of utilizing dumped waste as a practical resource for making concrete. In this regard, waste marble powder used a filler material replacing a smaller constant portion of cement, dumped iron ore tailings (IOT) were used as a partial replacement for fine aggregate in different proportions. Since waste materials are added in both cementitious and fine aggregate content, to improve the strength and to make the concrete denser and less porous ground granulated blast furnace slag (GGBS) and nano-silica (nS) were used as supplementary cementitious materials for cement. They were added in a constant replacement level of 7.5% and 0.5% respectively, with a constant replacement level of 7% of marble powder, making a 15% replacement of the cementitious materials by cement weight. The replacement percentages adopted for IOT were 0%, 20%, 30% and 40% by fine aggregate weight. 0.5% Steel fibres and a hybrid combination incorporating 0.25% steel fibre and 0.25% basalt fibres were also used to improve the concrete's tensile and flexural properties. The Specimens were subjected to various tests related to strength such as compression, flexure and few durability tests such as deterioration, sorptivity and porosity. The results were compared with traditional concrete. The optimum mix was identified as the one with 30% IOT and hybrid fibre combination.

Effects of different industrial waste materials as partial replacement of fine aggregate on strength and microstructure properties of concrete

This study aimed at investigating the effect of different industrial waste material as partial replacement of fine aggregate on strength properties of normal concrete. For economical and sustainability of natural resources, use of some industrial waste can demonstrate numerous benefits for the construction industry. Nevertheless, there is limited study on the use of industrial waste as replacement of fine aggregate in normal strength concrete especially, using alum sludge from water treatment plant as replacement of fine aggregate. The material used in this study as replacement of fine aggregate (river sand) was oven-dried alum sludge. While quarry dust and limestone dust were also employed as non-reactive industrial waste material, to identify the specific effect of oven-dried alum sludge in concrete. All the materials were crushed to obtain smaller particle size and then used as replacement of fine aggregate in different percentages (5, 10 and 15%). The results from the experiments shows that addition of industrial waste material improved the concrete density, compressive, flexural, and splitting tensile strengths. The result also shows that optimum replacement content of fine aggregate with industrial waste were 10% for oven-dried alum sludge, whereas 15% for quarry and limestone dust content that improved all strength properties investigated in this study. All industrial waste employed in this study as fine aggregate have proven to be a good filler material by filling the concrete internal void and improving the strength properties for a normal strength concrete.

Novel Gradation Design of Porous Asphalt Concrete with Balanced Functional and Structural Performances

To improve the permeability of porous asphalt concrete (PAC) with a small nominal maximum aggregate size (NMAS) of 10 mm (PAC10), a novel gradation design by excluding the 0.075–3 mm aggregate was developed. This study aims to evaluate the functional and structural performances of the novel PAC10 with various mineral filler contents, using the conventional PAC10 and 13 mm NMAS PAC (PAC13) as reference, and develop the optimum gradation of the novel PAC10. The performance properties evaluated include moisture susceptibility, durability, high-temperature stability, low-temperature cracking resistance and permeability. The results indicated that for the two conventional PACs with the same fine aggregate and mineral filler content, PAC10 had worse permeability and rutting resistance, similar moisture susceptibility and durability, and better low-temperature cracking resistance, compared with the PAC13. The novel PAC10 showed better permeability than the conventional PAC10. With the increase of the mineral filler content, the structural performance of the novel PAC10 is improved, but its permeability is decreased. With a mineral filler content of 6%, the novel PAC10 can have balanced functional and structural performances, which are equivalent to those of the conventional PAC13.

Applications of Gene Expression Programming and Regression Techniques for Estimating Compressive Strength of Bagasse Ash based Concrete

Compressive strength is one of the important property of concrete and depends on many factors. Most of the concrete compressive strength predictive models mainly rely on available literature data, which are too simple to consider all the contributing factors. This study adopted a new approach to predict the compressive strength of sugarcane bagasse ash concrete (SCBAC). A vast amount of data from the literature study and fifteen laboratory tested concrete samples with different dosage of bagasse ash, were respectively used to calibrate and validate the models. The novel Gene Expression Programming, Multiple Linear Regression and Multiple Non-Linear Regression were used to model SCBAC compressive strength. The water cement ratio, bagasse ash percent replacement, quantity of fine and coarse aggregate and cement content were used as an input for models development. Various statistical indicators, i.e., NSE, R2 and RMSE were used to assess the performance of the models. The results indicated a strong correlation between observed and predicted values with NSE and R2 both above 0.8 during calibration and validation for the Gene Expression Programming (GEP). The outcomes from GEP outclassed all the models to predict SCBAC compressive strength. The validity of the model is further verified using data of fifteen tests conducted in the laboratory. Moreover, the cement content in the mix was revealed as the most sensitive parameter followed by water cement ratio form sensitivity analysis. The GEP fulfilled all the criteria for external validity. The simple formulae derived in this study could be used reliably for the prediction of SCBAC compressive strength.

Permeability of self-compacting concrete made with recycled concrete aggregates and Portland cement-fly ash-silica fume binder

Permeability properties of self-compacting concrete (SCC) made with fine recycled concrete aggregates (FRCA), coarse recycled concrete aggregates (CRCA), and Portland cement-fly ash-silica fume binder are reported. Fresh and permeability properties of various SCC mixes were assessed. The results indicate that the increase in content of fine and coarse recycled concrete aggregates (RCA) in SCC tends to deteriorate the workability and permeability properties. The compressive strength also decreased with the inclusion of RCA. The substitution of 50% CRCA and 25% FRCA in SCC mix shows marginal decrease in hardened SCC properties as compared to SCC made with fine and coarse natural aggregates. Further, increase in FRCA content in SCC mix deteriorated the compressive strength and permeability properties. Furthermore, the addition of SF at 10% by weight of ordinary Portland cement was able to compensate the loss of permeability properties even for 50% substitution of both FRCA and CRCA.

Development of economic, practical and green ultra-high performance fiber reinforced concrete verified by particle packing model

Ultra High Performance Fiber Reinforced Concrete (UHPFRC) is a type of concrete which possess very high compressive strength (more than 150 MPa) and high ductility which makes it a suitable material for manufacturing pre-cast structural elements. Manufacturing this type of concrete in large-scale is however not appealing to industry which leads to limited application. The main reason for this can be attributed to the manufacturing cost of UHPC due to the high cementitious materials and fine aggregate (less than 600 μm) contents. This study focused on a step by step procedure making UHPFRC more practical, cost-effective and green by not only introducing coarse aggregate in the mix but also increasing the aggregate content, resulting in lower consumption of cementitious materials. The particle packing of the mix design developments were compared to the modified Andreasen & Andersen particle packing model and it was confirmed that an increase in cement content can result in a reduction in strength when the combined particle size distribution contains too many particles of a similar size. The final proposed mix designs per compressive strength generates 10 % less CO2 and 75 % more affordable than the typical commercial UHPFRC.

Study on Pervious Concrete by Partial Replacement of Silica Fume and GGBS with Cement and Addition of Glass Fibers

Pervious Concrete for the pavements proves to be an effective and along- term solution for the universal problem of abnormal decrease of ground water table. Pervious Concrete has a unique mix design and giving special properties to the concrete which makes the concrete porous , allowing water from precipitation and other sources to pass directly through , there by reducing run off volume and increasing ground water table. Inorder to reduce the damage being caused to the environment by the use of cement , inpervious concrete , cement is replaced with pozzolanic materials such as GGBS , silica fume sand to increase strength and durability , glass fibers in stipulated ratio are added to the concrete mixture. In this study ,the mix designs such as M30 and PC30 are considered . The fine aggregate is replaced with coarseaggregate by different ratios like 0% , 5% , 10% ,15%. by adding different pozzolanic matrals like GGBS, silicafume with glassfibers. To find the effectiveness of the use of pozzolancic and glassfibes, compressive strength conducted. The following Conclusions can be summarized by analyzing tests performed on PC specimens. A significant reduction of workability. And A progressive addition in compressive strength by increasing the percentage of fine aggregates and pozzolanic materials in mix. The conclusion of fine aggregate content in the specimen increases the density and increase the pozzolanic materials addition. And addition of silica fume and GGBS in the mixtures improve strength , compressive strength increases even after adding pozzolanic materials. Due to increase of fine aggregate content. For all replacement levels of PC with other mixes goes on decreasing in strength when compared with parent grade ofM30. While comparing with PC with Pozzolanic materials, For 7 days there is a drastic change for same replacement, and for 28 days itshowssimilar trend for 25% pozzolanic concrete and goes on decreasing for strength for compressive strength. For all replacement levels of PC with pozzolanic goes on decreasing in strength when compared with parent grade of M30. Compressive strength slightly increased by adding glass fibers to the allmixes.

Research on Shrinkage Chemical Properties of Cement Stabilized Macadam Material Based on a Multi-dimensional Expansion and Shrinkage Tester

In order to find out the shrinkage law of cement stabilized macadam material under specific conditions, this paper studied the expansion and shrinkage properties of cement stabilized macadam material under two environmental conditions, five kinds of cement dosage conditions, suspended compacted type and skeleton compaced type based on the multi-dimensional expansion and shrinkage tester. Through the test comparison, it is confirmed that the water loss rate of cement stabilized macadam material increases with the increase of cement dosage, showing a general change rule of rising first and then stabilizing. The average increase of the total water loss rate of suspended compacted cement stabilized macadam at room temperature was greater than that of the skeleton compacted cement stabilized macadam. The dry shrinkage strain also follows the above trend. Either at room temperature or under the conditions of dry shrinkage box, the water loss rate of suspended compacted cemeny stabilized macadam is higher than that of skeleton compacted cement stabilized macadam , which can be up to 3.23% higher. By comparing the temperature shrinkage coefficient under the high and low temperature environment, the temperature coefficient of the skeleton compacted cement stabilized macadam is smaller than that of the suspended compacted cement stabilized macadam. The temperature shrinkage coefficient of the suspended compacted cement stabilized macadam increases by 5.56% on average for each 0.5% increase of the cement dosage, and the temperature shrinkage coefficient of the skeleton compacted cement stabilized macadam increases by 6.33% on average. Through the comparative analysis of tests, it can be found that the anti-reflection crack ability of the skeleton compacted cement stabilized macadam material is better, and the fine aggregate content should be strictly controlled in the construction.

Optimizing manufactured sand content in mortars and its influence on fresh and hardened state

The shape and roughness of aggregates play a predominant role in the properties of cement mixes. Due to that, some regulations limit the content of manufacture fine aggregate at 30% of the total of fine aggregate in concrete. However, few design methods consider the shape and roughness surface of aggregates in the mix proportioning. This study presents an optimization method to increase the percentage of manufactured fine aggregates to be used, based on the void volume of the aggregates and their correlation with the fresh properties of mortars. To achieve that, the characteristics of the fresh and hard state were evaluated in order to carry out a comprehensive analysis on the influence of the method on the performance of mortars. From the results emerges that it is possible to maximize the content of manufactured aggregates without detrimental effects on compressive strength.

Spalling sensitivity and mechanical response of an ecofriendly sawdust high strength concrete at elevated temperatures

An eco-friendly high strength concrete (HSC) was developed with integration of wood waste (0, 5, 10, and 15%) in replacement to weight content of fine aggregate. Wood waste (sawdust) potentially a thermally degradable fiber was incorporated to enhance the fire endurance of high strength concrete. Mechanical strength and durability parameters of controlled and modified samples were explored along with the degradation on exposure to elevated temperatures. The investigated formulations were subjected to a maximum temperature of 800 °C on 5 °C/min ramp and then tested in the ambient conditions for the residual properties. Results depicted significant retention in compressive strength of sawdust high strength concretes (SD-HSC) at elevated temperatures with limited spalling sensitivity. Visual assessment along with micro-forensic evidences illustrate that SD-HSC exhibits reduced thermal cracking in macro, micro and the nano phase, in comparison with HSC. The experimental trends obtained from material property tests were used to develop simplified mathematical relationships that are helpful in performing analytical fire resistant studies for HSC formulations bearing sawdust grains. Conclusively, sawdust has been effectively utilized to develop an ecofriendly and fire resistant structurally applicable high strength concrete.

Investigation of aggregate moisture content variation and its impact on pavement performance of WMA

For warm mix asphalt (WMA), aggregates cannot be completely dried due to the low heating temperature, which further adversely affects the pavement performance. This study aimed to (1) analyze the effect of particle size, heating temperature and heating time on the variation in the moisture content in aggregates, (2) compare the interaction ability between warm mix asphalt binders and aggregates with different moisture contents from a rheological perspective and (3) to study the effect of aggregate moisture contents on the pavement performance of WMA. Results show that the quadratic function can be used to express the decline in moisture content over time. The decline rate of moisture content increases with the decrease in particle size. The moisture content of fine aggregate dominates that of the whole aggregate system. The decline rate of moisture content exhibits strong temperature sensitivity in the heating temperature ranging from 110 °C to 150 °C. The sensitivities of different evaluation parameters of the asphalt-aggregate interaction were compared by sensitivity analysis. With the decrease in the moisture content of aggregates, the pavement performance of WMA can be improved. These findings provide understanding on the variation in aggregate moisture content during the heating process, and prove that reducing aggregate moisture content can improve the pavement performance of WMA.

Thermo-mechanical and moisture absorption properties of fly ash-based lightweight geopolymer concrete reinforced by polypropylene fibers

An experimental investigation on the thermo-mechanical and moisture absorption properties of lightweight geopolymer concrete prepared with fly ash, NaOH, sodium silicate and Polypropylene Fibers (PF) is presented in this study. The effects of dry density, NaOH, PF, aggregates and hydrophobic agent on the compressive strength, thermal properties and moisture absorption were studied. Results indicate that thermo-mechanical properties of Fly ash-based Lightweight Geopolymer Concrete (FLGC) strongly depend on the dry density, NaOH, PF and aggregates contents. The increase in dry density and fine aggregate contents resulted in higher compressive strength and thermal conductivity. NaOH within mass ratio of 0–10% is able to enhance thermo-mechanical properties. The optimal compressive strength was achieved when the length and content of the PF was 12 mm and 0.5% respectively. Meanwhile, PF in the range of 0–1% can also increase thermal conductivity and enhance moisture absorption. The increase in coarse aggregate ranging from 0 to 15% led to reduced dry density and thermal conductivity and enhanced moisture absorption, but did not affect compressive strength. Interestingly, the decrease in fine aggregate with the same content had the opposite impact to the moisture absorption in comparison to the coarse aggregate. However, the moisture absorption can be considerably weakened by surface waterproofing treatment which makes the enhanced thermal performance durable. Therefore, the FLGC reinforced by PF has excellent thermo-mechanical properties and can also be engineered to be an environmentally friendly and durable thermal insulation material with the assistance of waterproofing treatment.

Study on pervious concrete pavement mix designs

Increased precipitation in recent years due to the effect of climate change is leading to increased surface runoff and water logging in urban areas while impervious concrete or asphalt covering of urban lands hinders groundwater recharge. However, Pervious Concrete Pavements have the capacity of functioning as a Sustainable Urban Drainage System (SUDS) by allowing surface water to infiltrate downwards through the porous structure of the pavements, thereby minimizing flooding risks, recharging ground water, reducing run off and peak flows, alleviating the precipitation load on overstressed drainage systems, and improving water quality by capturing pollutants. This research provides an overview on pervious concrete mix designs and their effect on strength and permeability. Materials of pervious concrete include those used in conventional concrete, however eliminating the fine aggregate content. Different mix designs have been prepared and tested to understand the behavior of Pervious Concrete and recommend an ideal mix. The findings from the Compressive Strength Test and Standard Test Method for Infiltration Rate of in place Pervious Concrete, investigate the gradually varying properties of pervious concrete with changes in the mix which are reported and discussed. Results indicate that a fine balance between compressive strength and permeability is not possible however pervious concrete pavements can be an acceptable alternative when used in low volume and low impact areas.

Modification of Lime‐Fly Ash‐Crushed Stone with Phosphogypsum for Road Base

In order to increase the recycling of phosphogypsum waste, this study explored the feasibility of using phosphogypsum to replace some of the lime and aggregate in the lime‐fly ash‐crushed stone mixture which is a widely used road base material in China. For this purpose, compaction, compressive strength, composition structures, wetting‐drying cycle tests, and shrinkage tests were carried out on the lime‐fly ash‐phosphogypsum‐crushed stone composite to investigate its performance. The results indicate that lime‐fly ash‐crushed stone modified with phosphogypsum has the required strength of the road base material and favourable performances in environment (wetting‐drying cycle) stability. The image processing analysis and shrinkage tests demonstrated that phosphogypsum can significantly improve the compactness and shrinkage performance of lime‐fly ash‐crushed stone mixture. A suitable content of phosphogypsum and a reasonable content of fine aggregate are conducive to improving the roadway engineering properties (i.e., decreasing shrinkage cracks and increasing compressive strength) of lime‐fly ash‐phosphogypsum‐crushed stone composites.

GREEN TECHNOLOGY THROUGH POROUS CONCRETE

This research uses stone ash waste from the stone crusher industry to preserve the environment. This material is an ingredient in making normal concrete. The use of stone ash as a substitute for sand is expected to increase the compressive strength in the planned slump and can optimize the use of rock ash waste to reduce environmental pollution that occurs. This study uses an experimental method with a total of 32 pieces of specimens. Each variation consists of 3 samples with a variety of fine aggregate levels of 40%, 44%, and 46%. The test object is a concrete cylinder with a diameter of 15 cm and a height of 30 cm. Test results for compressive strength at seven days for fine aggregate content variations of 40%: 22.25 Mpa; 44%: 24.30 Mpa; 46%: 17.08 MPa. Test results of compressive strength at the age of 14 days for variations in fine aggregate levels of 40%: 26.10 Mpa; 44%: 28.51 Mpa; 46%: 20.04 Mpa. Test results of compressive strength at the age of 21 days for fine aggregate content variations of 40%: 28.18 Mpa; 44%: 30.78 Mpa; 46%: 21.63 MPa. With these results, the Porous concrete produced can be used as preservation and maintain environmental protection. This product very cheap when compared to the original concrete, which calculated 22 U$ per square. The use of porous concrete has an impact on people's behavior that will preserve the environment, especially water content in the soil.

Multi-modified effects of varying admixtures on the mechanical properties of pervious concrete based on optimum design of gradation and cement-aggregate ratio

The mechanical properties of pervious cement concrete (PCC) could be significantly enhanced through adding admixtures. This study was to investigate the multi-modified effects of different types of admixtures based on optimum design of gradation and cement-aggregate ratio (C/A). The influence of gradation and C/A on the compressive strength and porosity of PCC were firstly studied. Then a further optimum C/A for a constant gradation of aggregates with adhesion mixtures including the water-reducing agent (WA) and reinforcing agent (RA) was conducted. More types of admixtures were further added to enhance the compressive strength. In addition, these single admixtures added into the graded PCC were also comparatively explored. The results on the compressive strength revealed that 1) adding admixtures (single or multiple) was in general more effective than increasing C/A or the content of fine aggregate, while increasing C/A was slight better than increasing the fine aggregate; 2) The two adhesion admixtures wrapped more cement pastes without the phenomenon of cement segregation, which resulted in a higher optimum C/A and extra fillers from the surplus cement; 3) The multi-modified effect by three physical fibers were all excellent compared to those of two fine solid wastes, based on the two adhesion admixtures; 4) There existed fairly good relationships between apparent density and compressive strength of the graded PCC both with these single and multiple admixtures.

Use of industrial waste as partial fine aggregate replacement in SCC

In the current scenario, SCC is used in the variety of massconcreting applications. But SCC involves usage of more quantities of binder and fine aggregate content compared to conventionally vibrated concrete (CVC). The availability of basic constituent materials required for preparing the concrete in the entire world is facing a majorcrisis. For example, the construction industry has faced the non-availability of river sand since it is the principal ingredient that contributes the homogeneity in concrete. The experimental investigation was planned with the total of ten SCC mixes using industrial wastes namely copper slag (CS) and steel slag (SS) from 0% to 50% (with an increment of 10%) as fine aggregate replacement along with one control SCC (SCC0). The water-powder (w/p) ratio of 0.38, the dosage of Super plasticizer (SP) as 1.5% by the weight of cement and viscosity modifying agent VMA as 0.15% by the weight of cement were arrived based on the laboratory test trials. The fresh property tests were conducted in greener SCC according to EFNARC guidelines. The mechanical properties(compressive strength and split-tensile) were determined after 28 days of curing. Keywords: Compressive strength; copper slag; self-compacting concrete; splitting tensile strength; steel slag.

Mechanical properties of crumb rubber-rice husk ash concrete as a rigid pavement material

Waste tyres accumulate very quickly in a landfill as a result of the fast development of the transport industry, and mainly automobiles. The polymeric waste has limited usage and is rarely employed in a highly economic and viable product. A rigid pavement material needs to have high mechanical properties and durability when exposed to aggressive environments. In this research, a combination of waste tyre with rice husk ash and Portland Cement Composite (PCC) as a primary binder was designed to produce concrete that meets the requirements of flexural strength value of the rigid pavement based on the Indonesian Standard from Bina Marga 2018. Eight mixes with a variety of water/cement ratio (0.30-0.40), crumb rubber (2.5-7.5%), and rice husk ash (7.5-10%) were designed in this research. The control mix was PCC concrete. The crumb rubber substituted the fine aggregate content, while the rice husk ash replaced the cement content in concrete. The specimens were cast and subsequently cured in water pond up to 28 days. The mechanical properties of concrete, namely compressive strength and flexural strength were determined for all variations. Based on the results, Mix 1 with w/c ratio of 0.30, crumb rubber of 5%, and rice husk ash of 10%, performed both the highest compressive strength and flexural strength values of 36.38 MPa and 4.53 MPa, respectively, after 28 days. Both values fulfilled the requirements of the Indonesian Standard Bina Marga 2018. It can be concluded that an appropriate combination of crumb rubber and rice husk ash improves the mechanical properties of the concrete and has potential as a rigid pavement material.