Fresh and hardened properties of high-strength concrete incorporating byproduct fine crushed aggregate as partial replacement of natural sand

2021 ◽  
Vol 15 (1) ◽  
pp. 124-135
Author(s):  
Dammika P. K. Wellala ◽  
Ashish Kumer Saha ◽  
Prabir Kumar Sarker ◽  
Vinod Rajayogan
2014 ◽  
Vol 567 ◽  
pp. 381-386 ◽  
Author(s):  
Nasir Shafiq ◽  
Muhd Fadhil Nuruddin ◽  
Ali Elheber Ahmed Elshekh ◽  
Ahmed Fathi Mohamed Salih

In order to improve the mechanical properties of high strength concrete, HSC, several studies have been conducted using fly ash, FA. Researchers have made it possible to achieve 100-150MPa high strength concrete. Despite the popularity of this FAHSC, there is a major shortcoming in that it becomes more brittle, resulting in less than 0.1% tensile strain. The main objective of this work was to evaluate the fresh and hardened properties of FAHSC utilizing chopped basalt fiber stands, CBFS, as an internal strengthening addition material. This was achieved through a series of experimental works using a 20% replacement of cement by FA together with various contents of CBFS. Test results of concrete mixes in the fresh state showed no segregation, homogeneousness during the mixing period and workability ranging from 60 to 110 mm. Early and long terms of compressive strength did not show any improvement by using CBFS; in fact, it decreased. This was partially substituted by the effect of FA. Whereas, the split and flexural strengths of FASHC were significantly improved with increasing the content of CBFS as well as the percentage of the split and flexural tensile strength to the compressive strength. Also, test results showed a progressive increase in the areas under the stress-strain curves of the FAHSC strains after the CBFS addition. Therefore, the brittleness and toughness of the FAHSC were enhanced and the pattern of failure moved from brittle failure to ductile collapse using CBFS. It can be considered that the CBFS is a suitable strengthening material to produce ductile FAHSC.


2016 ◽  
Vol 857 ◽  
pp. 183-188
Author(s):  
C. Mohan Lal ◽  
Vontary Sai Srujan Reddy

High strength concrete has become a design requirement in recent years due to increase in number of infrastructure projects. This paper presents the effect of incorporating Ultra Fine Slag (UFS) and steel fibre to obtain high strength concrete. To achieve target strength of about 80 MPa, it is proposed to the replacement of cement of 10%, 20% and 30% with UFS and incorporating 0.5% and 1.0% fibre in concrete. An experimental investigation is carried out to find the mechanical properties of the concrete. From the test results, it was observed that a compressive strength of 95 MPa was achieved at 30% replacement of cement with UFS and 1.0% fibre content. In addition, there was a significant improvement in split tensile strength and flexural strength of the concrete. This study demonstrates that a high strength concrete can be obtained from partial replacement of cement with UFS and addition of steel fibre.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Iswarya Gowram ◽  
Beulah M ◽  
MR Sudhir ◽  
Mothi Krishna Mohan ◽  
Deekshith Jain

Urbanization and industrialization have dramatically increased the manufacture of cement causing substantial pollution of the environment. The primary global concern related to cement manufacture has been the management of the large carbon footprints. The usages of environmentally friendly cementitious materials in the construction of structures have proved to be a viable option to deal with this environmental concern. Therefore, it is necessary to further explore the usage of cementitious materials which can replace cement albeit partially. In this direction of research, two such cementitious materials, namely, natural zeolite and metakaolin have been investigated in this study. High-strength concrete M60 with natural zeolite and metakaolin as the partial replacements for the cement has been prepared in this work. Polycarboxylic ether-based superplasticizer solution has been used to enhance workability. The test specimen cast and cured for 3, 7, 28, 60, and 90 days at ambient room temperature has been tested for compressive strength, split tensile strength, and flexural strength as per the Indian standards. The optimum mix of high-strength concrete thus manufactured has met the Indian standards, and the combination of cement +5% natural zeolite +10% metakaolin has exhibited the highest compressive, split tensile, and flexural strengths at 90 days of curing. Natural zeolite and metakaolin when used in smaller proportions have increased the concrete strength, and these materials are recommended for partial replacement of cement.


2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Aysegul Petek Gursel ◽  
Claudia Ostertag

Aggregate consumption rates have now exceeded natural renewal rates, signaling shortages both locally and globally. Even more concerning is that the worldwide markets for construction aggregates are projected to grow at an annual rate of 5.2% in the near future. This increase is attributed to rapid population growth coupled with the economic development worldwide. In terms of material availability, one of the most vulnerable regions is the Asia-Pacific region specifically, Singapore, where there is higher demand but limited availability of natural sand and gravel for use as aggregates in concrete construction projects. This paper focuses mainly on the environmental impacts of fine aggregate alternatives used in high-strength concrete applications in Singapore, which is one of the major global importers of natural sand following China. Singapore has been experiencing political and environmental challenges linked to the shortage of natural sand use as aggregates, even while the demand is increasing in the construction sector. Copper slag, a readily available waste material from shipyards in Singapore, is a possible replacement material for a portion of the natural sand in concrete mixtures, thus sustaining the projected growth in the region. A life-cycle assessment approach is applied to investigate the environmental impacts of copper slag and its alternative use as natural sand in high-strength concrete applications in Singapore. The system boundary consists of the major production processes of concrete constituents (including Portland cement and fine and coarse aggregates, with CS considered as fine aggregate) from a cradle-to-gate perspective, consisting of relevant life-cycle phases of raw materials extraction, transportation, and production processes at the relevant facility where the production occurs. Output from the assessment is provided in terms of embodied energy use and air emissions of concrete mixes with varying percentages of copper slag as fine aggregate. Results show that environmental impacts of aggregates decrease with the increasing substitution rate of natural sand with copper slag when calculated on the basis per unit volume of the concrete mix. For example, 40% and 100% sand replacements with copper slag result in a reduction of 8% and 40% in embodied energy, 12% and 30% in global warming potential, 8% and 41% in acidification, and 7% and 35% in particulate matter formation, respectively. Normalized impacts (i.e., normalized with respect to compressive strength) are observed to remain at almost similar levels for concrete mixes with up to 40% natural sand having been replaced with copper slag. Therefore, it is recommended that replacement of fine aggregates by 40–50% of copper slag (by weight) will produce concrete mixtures with comparable environmental impacts while maintaining feasible durability and strength properties.


The High strength concrete defined as per IS 456 as the concrete having characteristic compressive strength more than 65 MPa. The self-compacting concrete has lot of advantages including concreting at congested reinforcement locations, better finish, good compaction etc. The inclusion of fibers in the concrete mix decreases the brittle nature of concrete thereby the ductility increases. Different types of fibers are available for inclusion in concrete like steel, glass, polypropylene, basalt, etc. In the present investigation, high strength concrete having characteristic strength of 90 MPa was developed and hooked ended steel fibers are used and the hardened properties are determined. Steel fibers having diameter of 1 mm and lengths of 25 and 50 mm were added to concrete in 0.125%, 0.25% and 0.5% by volume of concrete. Three hardened properties compressive strength, split tensile Strength and flexural strength were determined. Out of the two lengths of fiber i.e with two aspect ratios, the fiber with 50 mm length yielded better results.


Author(s):  
Jamshed Alam

An experimental analysis was conducted to study the effects of using copper slag as a fine aggregate (FA) and the effect of fly ash as partial replacement of cement on the properties high strength concrete. In this analysis total ten concrete mixtures were prepared, out of which five mixes containing different proportions of copper slag ranging from 0% (for the control mix) to 75% were prepared and remaining five mixes containing fly ash as partial replacement of cement ranging from 6% to 30% (all mixes contains 50% copper slag as sand replacements). Concrete matrix were tested for compressive strength, tensile strength and flexural strength tests. Addition of copper slag as sand replacement up to 50% yielded comparable strength with that of the control matrix. However, further additions of copper slag, caused reduction in strength due to an increment of the free water content in the mix. Concrete mix with 75% copper slag replacement gave the lowest compressive strength value of approximately 80 MPa at 28 days curing period, which is almost 4% more than the strength of the control mix. For this concrete containing 50% copper slag, fly ash is introduced in the concrete to achieve the better compressive, split and flexural strengths. It was also observed that, introduction of the fly ash gave better results than concrete containing 50% copper slag. When concrete prepared with 18 % of fly ash, the strength has increased approximately 4%, and strength decreased with further replacements of the cement with fly ash. Hence, it is suggested that 50% of copper slag can be used as replacement of sand and 18% fly ash can be used as replacement of cement in order to obtain high strength concrete.


2021 ◽  
Vol 18 (2) ◽  
pp. 89-101
Author(s):  
Aidan Newman ◽  
◽  
Nuradila Izzaty Halim ◽  
Muhd Norhasri Muhd Sidek ◽  
Hamidah Mohd Saman ◽  
...  

High strength concrete (HSC) is an amazing breakthrough in the history of construction material. Due to its high strength, durability, and economic value, it has been used in large-scale construction with a unique structure design not achievable by conventional concrete. However, HSC uses a high amount of cement powder which contributes to its overall strength. However, it will require high cement consumption and increases carbon dioxide emission. Waste paper sludge ash (WPSA) is utilised in cement and has improved concrete properties. Nano engineered WPSA might further enhance HSC capabilities. This research focused on the physical and fresh properties of HSC with partial replacement of nano-engineered WPSA to cement through experimental investigation. The HSC produced in this research has a targeted strength of more than 40MPa with a fixed water-cement ratio of 0.2. The WPSA was oven-dried and was sieved to a particle size of 212 micrometers. Then, it was milled until a nano-size particle is obtained. The nano WPSA is used to replace cement in the HSC mix with a replacement percentage of 1%, 3%, 5%, 7%, and 10%. The new properties of the concrete were measured by conducting the flow table test, and the physical property was determined by conducting the compressive test. Compressive tests were conducted for 1, 3, 7, 14, and 28 days with a cube sample size of 50mm x 50mm x 50mm. This research shows that 1% of nano WPSA replacement tends to improve the compressive strength of the HSC concrete by 10.7% compared to the control sample. On the other hand, the 1% replacement of nano WPSA in HSC did not affect the concrete's workability compared to the control sample. The conventional HSC properties were improved with less usage of cement with the use of WPSA.


2018 ◽  
Vol 7 (4.20) ◽  
pp. 222 ◽  
Author(s):  
Haitham Al-Thairy

The shortage and high cost of quarries sand in some regions around the world has motivated engineers and researchers to investigate the possibility and feasibility of using other materials to be used as a fine aggregate in concrete mixtures. The main objective of this research is to experimentally investigate the effect of using river sand as a partial replacement of the ordinary quarries sand on the mechanical properties of normal and high strength concrete. Nine concrete mixtures were prepared and tested in terms of fresh and hardened properties using different replacement ratios of the required proportion of the normal sand. Four replacement ratios were used for normal strength concrete (NSC) which are: 0%, 25%, 50% and 75%, whereas, five replacement ratios were used for high strength concrete (HSC) namely: 0%, 35%, 60% and 90%. For each strength grade, the test parameters of the prepared mixtures included compressive and tensile strength. The experimental test results have revealed that it is possible to obtain a normal and high strength concrete with acceptable compressive and flexural strengths values by using river sand with replacement ratios up to 25% and 35% for NSC and HSC, respectively. When the replacement ratios were increased to more than the aforementioned ratios, the strength of the concrete decreased accordingly.  


Sign in / Sign up

Export Citation Format

Share Document