Control Concrete Research Articles

Physical, mineralogical, thermal, and mechanical properties of aerogel-incorporated concrete exposed to elevated temperatures

This paper investigated the physical, mineralogical, thermal, mechanical, and microstructural performances of concretes with four aerogel contents (i.e., 0, 5, 10, and 20 vol %) and after exposure to elevated temperatures (i.e., 200, 400, 600, 800, and 1000 °C). Mechanisms both of the heat-induced degradation and of the aerogel in mitigating the degradation of concrete were unveiled. Specimens after 200 °C exposure bear the same mineralogical compositions as those at 20 °C. After being exposed to 400 °C and 600 °C, portlandite disappeared. Dolomite and C–S–H still occurred after 800 °C exposure whereas disappeared after 1000 °C exposure. The residual strength of specimens decreased with an increase in the exposure temperature, except for the unexpectedly elevated ones after 400 °C exposure. Incorporating aerogel into specimens alleviated the strength loss after exposure to elevated temperatures, especially after 200–600 °C exposure. For instance, the strength losses of A0, A5, A10, and A20 after 600 °C exposure are 39.4, 39.1, 25.9, and 19.1%, respectively. Aerogel maintained its 3D nano-structure after 400 °C exposure; their thermal insulation properties remained functional. The heat flow was significantly retarded while meeting aerogel particles in the concrete. After 600 °C exposure, the gradual fusion of aerogel thickened the particle skeleton, and enhanced the stiffness and strength of the skeleton, making the aerogel-incorporated concrete resist higher loads than the control concrete. The sintering properties of aerogel play a vital role in mitigating the heat-induced degradation of concrete.

Performance of Concrete Developed by Enhanced Gradation of Natural Fine River Sands by Partial Replacement of Waste Quarry Dust

As construction activity continues to increase on a daily basis, the demand for fine and coarse aggregates is also rising. However, relying on a few sources would quickly deplete the natural sources of aggregates. In Lahore, Punjab, Pakistan, costly coarse pit sand from northern areas is used for concrete, as the local river sands (Ravi and Chenab) are fine and do not meet ASTM specifications for fine aggregates. To alleviate the pressure on one source, it is necessary to improve the gradation of natural river sand by utilizing quarry dust obtained during the process of crushing rock into crushed stones. This study conducted detailed experimental work to enhance the gradation of natural river sand by adding normalized quarry dust. Concrete mixes with three strengths of 21 MPa, 28 MPa, and 35 MPa were prepared by partially replacing natural river sand with quarry sand. Workability and hardened concrete properties were evaluated for all mixes, and cost analysis was performed for 28 MPa concrete. The results were compared with control concrete made with coarse pit sand. When river sand was enhanced by combining 40% river sand and 60% normalized quarry dust, the resulting sand met ASTM requirements. Furthermore, when some fines were removed from river sand and replaced with 50% normalized quarry dust, the sand also met ASTM grading requirements. The compressive and flexural strengths of concrete made with enhanced sand gradation increased by 10–25% and 9–17%, respectively, for 28 MPa concrete compared to the control concrete. Cost analysis showed that 28 MPa concrete made with enhanced natural river sand gradation was 8.6% more economical than concrete made with coarse pit sand.

Exploring the performance of Fe-Al rich sand in fly ash-based cementitious system in the context of a sustainable built environment

This research seeks to manufacture concrete by replacing fine aggregates in concrete with Fe-Al rich sand obtained from laterite scraps (mine waste) and fly ash-based cement. To reduce the colossal dumping of laterite scraps and curtail the utilisation of virgin aggregates, this study was done to utilise the laterite scraps effectively in concrete. In this study, laterite scraps were collected as rocks and processed into Fe-Al rich fine aggregates. The processed Fe-Al rich sand was employed in various amounts and substituted as fine aggregates ranging from 0 % to 100 % at 25 % intervals. The morphological properties of raw materials, clay content percentage, workability, strength, microstructure, and phase evolution studies on Fe-Al rich sand-based concrete were investigated. The workability tests such as slump, compaction factor, Vee Bee consistency, and flow table indicated that the workability values of all the Fe-Al rich sand-based mixes were lesser than the control mix. The compressive strength, splitting tensile strength, and flexural strength values of Fe-Al rich sand-based concrete were reported to be greater than those of control concrete, but up to 50 % level of replacement, they demonstrated higher values. Furthermore, the decline in strength above 50 % was evaluated in comparison to that of conventional specimens. Microstructure and phase evolution studies on Fe-Al rich sand-based concrete revealed that the strength of Fe-Al rich sand-based concrete mixes changed as hydration products formed. This work further iterates that replacing natural fine aggregates with Fe-Al rich sand as a partial alternative in concrete has a significant ecological and long-term benefits.

Experimental Characterization of the Mechanical Properties of Concrete Based on Glass-Powder

Abstract Annually, there is an enormous amount of glass waste created worldwide, yet only a small portion of that material is recycled. Recovering waste glass (WG) in concrete demonstrates excellent progress in lowering the amount of glass. Researchers have found that adding waste glass to concrete improves its qualities; WG can be utilized as powder, fine as well as coarse aggregate. However, the question that arises is how this powder added to concrete improves, or at least maintains, the mechanical properties of the concrete despite the reduction in the cement quantity. The aim of the present paper is to investigate the behavior of concrete with the addition of glass powder. For this purpose, a control concrete and concretes were prepared with 10%, 15% and 20% of the cement content of the glass powder, based on the same concrete formulation and by varying the W/C ratio. In the hardened state, the addition of glass powder up to 20% of the cement content, generated an increase in compressive strength at 28 days; this increase is caused by the reaction between the glass powder and the lime released during the hydration of Portland cement and creates a binder called hydrated calcium silicate (S-C-H) (pozzolanic reaction). The latter plays an important role in increasing the strength of concrete, and since the fineness of the glass powder is similar to that of cement, it has a role of filling, and accelerates the pozzolanic reaction. For an addition of 20% to 30% of pozzolan, theoretically we could react all the lime produced by the hydration of Portland cement. Therefore, beyond 25% or 30% of the glass powder, the strength is affected, which has been confirmed by many researchers. Finally, it can be concluded that the use of glass powder in concrete improves its mechanical behavior compared to ordinary condition, but with a limited percentage of 20% of the cement content.

Performance on steel fiber reinforced concrete using metakaolin

Most of the common building material used today in the globe is cementing concrete. Its widespread use is due to the fact that it offers outstanding workability as well as can be shaped into whichever desired form. Since normal concrete is weak under stress, steel bars are included into cement concrete to increase its tensile strength. Massive tensile strains are applied to the concrete cover as a result of the expansion caused by internal reinforcement corrosion, which leads to cracking. Usage of fibers in concrete is an effective technique to arrest the extensive cracking and improves the mechanical characteristics of concrete. When compared to other forms of fibre, steel fibres are used for experiments more often because to their ductility, high tensile strength, ability to stop the spread of fractures, enhanced bond strength, etc. Using metakaolin as a cement substitute, the primary goal of the current experimental effort has to appraise the mechanical assets of concrete using steel fiber. In total, fifteen cubes, fifteen cylinders, and fifteen beams were casted for the experimental task. It has been explored how steel fibres and metakaolin change the mechanical characteristics of M25 grade concrete. By concrete volume, fibre content was modified in increments of 0.25 to 1%. 15% of the weight of the cement was composed of the metakaolin. With the purpose of determining the impact on the mechanical chacteristics of normal concrete, the testing outcomes of concrete using steel fiber and metakaolin are compared with control concrete. The strength of concrete in compression, tension, and flexure improved by 20.83%, 34.90%, and 72.91%, respectively, after the addition of 1% steel fibre and 15% metakaolin. Concrete using metakaolin has been discovered to have a little greater density than unreinforced concrete, which contributes to the enhanced mechanical characteristics of the concrete.

Performance evaluation of alkali activated slag based recycled aggregate pervious concrete

The present study attempts, a detailed evaluation of the strength performance of Alkali Activated Slag based Pervious Concrete (AASPC) mixes, containing fly ash and ground granulated blast furnace slag (GGBS) as binders. Fly ash and GGBS, by-product obtained from thermal power plants and steel industries respectively, is incorporated in the AASPC mixes as a full replacement to ordinary Portland cement (OPC). Initially OPC and AASPC mixes are designed to obtain M30 grade. OPC based pervious concrete is considered as control concrete. Pervious concrete is a type of concrete that has a high-water permeability and a higher void content than regular concrete.Experiments investigates the effect of the addition of Recycled Coarse Aggregate (RCA) on the physical and mechanical properties of alkali activated pervious concrete. Certain physical test has been conducted on recycled coarse aggregate to check the quality of aggregates, RCA varying percentage in 0, 25, 50, 75 and 100%, in the mixes. All mixes of alkali activated pervious concrete includes 50% of GGBS and 50% of fly ash from total binder content. Alkali activators used are, sodium hydroxide pellets and sodium silicate liquid. Workability of the alkali activated pervious concrete has a low slump value compare to the control concrete, but the workability of pervious concrete with cement is equal to alkali activated pervious concrete and workability will decreases with increase in RCA percentage because has a high capacity of water absorption. Compressive strength of alkali activated pervious concrete has increased by 23% compared to the OPC based pervious concrete and then there will be a decrease in compressive strength with increase in RCA percentage. The flexural strength and split tensile strength results for both the alkali activated pervious concrete and OPC based concrete shows almost similar values. Permeability and void ratio results shown increase with increase in RCA percentage in AASPC.

Experimental study on bio-concrete for sustainable construction

Concrete, a widely used building material, is highly susceptible to cracking, significantly reducing its lifespan and leading to expensive repairs. Cracks may occur in both the plastic and hardened stages due to various reasons such as formwork movement, plastic settlement, weathering, drying shrinkage, and thermal stress, among others. While it is impossible to prevent cracks from occurring, there are several techniques available for repairing them. However, some of these methods, such as the use of chemicals and polymers, have been found to be harmful to both human health and the environment, and they only provide temporary solutions. Alternatively, microbial self-healing concrete has been shown to be a promising approach, due to its compatibility with concrete and effective bonding ability. Self-healing concrete or bacterial concrete is a type of concrete that can repair structural flaws by filling them with bacteria that cause a biological reaction that seals the crack. Microbial concrete is a sustainable solution to reduce and repair concrete cracks compared to passive treatments such as chemical sealants which have several limitations. This article provides an overview of the microbiological methods employed for manufacturing calcium carbonate, which is used in microbial crack therapy. It was observed that the compressive strength of biomimicry concrete was found to be greater than ordinary concrete. It yields 15% greater value than control concrete for split tensile strength test. The flexural strength was found to be 30% more than control concrete. It has also been found that it has the capability to withstand larger strain, i.e., even after the formation of cracks, the specimens did not collapse. The paper also discusses the potential issues associated with this technique and offers suggestions for further research.

Comparative study on sugarcane bagasse ash and banana peel powder on concrete and its properties

With increasing infrastructural demand in today’s world and people being stuck to the traditional procedures of construction, there is definitely a need and scope for new research in this sector. Cement industries having a major impact on carbon footprint and with sustainable materials being dumped in landfill, a huge opportunity is there to utilize the supplementary cementitious materials. With extensive research already done on materials like Fly Ash and GGBS, we would like to extend our research on Sugarcane Bagasse Ash (SCBA) and Banana Peel Powder (BPP). Various physical properties of the materials that include specific gravity and consistency were conducted for cement, sugarcane bagasse ash and banana peel powder. Compressive strength, splitting tensile strength and flexural strength tests were conducted on specimens of M40 grade concrete with 5%, 10%, 15% cement replacement by SCBA and 1%, 2%, 3% cement replacement by BPP for 7, 14, 28 days curing time. All mix design calculations were done according to IS 10262:2019. Then, comparison of mechanical properties of both concrete was done with respect to control concrete.

Partial substitution of the cement by cinder power in the composition of High Strength Concrete (HSC)

The current experimental inquiry in this work aims to produce high strength concrete of grade M80 by using cinder powder as a substantial replacement for conventional Portland cement. ACI 211-4R was used to develop the mix design for M80 concrete mix. The concrete samples are subjected to hardened property tests. The specimens were made with several percentages of cinder replacement, such as 0%, 2.5%, 5%, 7.5%, and 10%, and binder ratios of 0.35 with super plasticizer. To ascertain the compressive strength of the concrete, the concrete's compressive strength, cubes of 100 × 100 × 100 mm are cast. By casting cylinders with a diameter of 100 mm and a height of 200 mm, it is possible to determine the tensile strength of concrete. At the age of 28 days, this mixture's compressive strength was found to be 92.25 MPa, and the best results were obtained when cinder powder was substituted for OPC in 5% of the mix together with super plasticizer and 0.35 water to binder ratio. Similarly split tensile and flexural strength performance have been upgraded upto 25.31% and 16.32% with for optimized 5% substitution of cinder powder compared to control concrete.

Mechanical and Durability Performances of Alkali-resistant Glass Fiber-reinforced Concrete

Concrete, being the most widely used construction material in the world, lacks strength in direct tension and flexure. Attempts to reinforce concrete in tension include the use of steel rebars to strengthen the tensile side of concrete as well as the use of discrete fibers as a reinforcing medium. The study conducted in this manuscript details the effects of including alkali-resistant glass fibers in concrete. Mechanical strength, such as strength in compression and flexure, chord modulus of elasticity and bond pull-out strength, have been measured along with porosity and resistance to accelerated carbonation. Five different water to binder ratios in a range of 0.4 to 0.6 had been used to prepare the design mix proportions. The optimum fiber dosage was found to be 1.5% by weight of cement used. The same had been adopted in the design mix proportions. The average increase in compressive strength and flexural strength was 13% and 28%, respectively. Alkali-resistant glass fiber concrete showed less resistance to carbonation when compared to control mix. Results indicate that glass fibers play a predominant role in providing flexural strength to concrete. The pull-out strength of fiber was added to extra post-cracking flexural strength. The inclusion of alkali-resistant glass fibers imparted a maximum addition of 44% increase in the flexural strength compared to control concrete. The inclusion of alkali-resistant glass fibers in concrete paves the way for a leaner mix and eradicates the possibility of congestion of steel reinforcement for certain structures. KEYWORDS: Alkali-resistant glass fibers, Accelerated carbonation, Bond strength, Compressive strength, Flexural strength.

A Comprehensive Evaluation of the Mechanical Properties of Rubberized Concrete

Most metropolitan areas in the world are facing major solid-waste-disposal problems. The solid-waste problem is considered one of the major environmental problems that countries and environmental organizations are paying increasing attention to at present, not only due to its negative effects on public health and the environment, but also due to the dangers it may cause to the nearby residential communities. One of the visible solutions is to reuse solid waste as a partial replacement of concrete constituents. In this investigation, fine aggregate was replaced with crumb rubber at four different volumetric percentages, ranging from 5 to 20% with a 5% step size. A novel treatment technique based on a combination of chemical and thermal treatments of a crumb rubber surface was adopted. A superplasticizer was added to improve both the workability and the strength of the concrete mixtures. The mixtures were assessed in fresh and hardened phases and compared with a control mix. In the fresh phase, the mixtures were evaluated regarding workability and wet density; and in the hardened phase, compressive strength after 180 days, tensile and flexural strength after 90 days, dry density, and absorption were investigated. Additionally, the mixes were assessed using non-destructive tests, namely, the ultrasonic pulse velocity test, rebound hammer test, and core test. The results showed that the addition of rubber particles to concrete decreased the compressive strength, tensile strength, and flexural strength in comparison with control concrete. An empirical equation based on combined analysis with R2 = 0.95 was derived. At the age of 180 days, the compressive strength of rubberized concrete varied from 34 to 42 MPa. From a structural point of view, its strength is regarded as acceptable.

Reuse of clay brick and ceramic waste in concrete: A study on compressive strength and durability using the Taguchi and Box–Behnken design method

This study investigated the compressive strength and durability of concrete containing clay brick waste powder (CBWP) and ceramic waste aggregate (CWA). First, we applied the Taguchi and Box–Behnken design method to find the optimal conditions for ensuring the maximum compressive strength of concrete. We considered three factors, including the amount of CWA, the amount of CWBP, and the water–cement ratio in the concrete mixture, as factors influencing the compressive strength of concrete. Second, we studied the durability of concrete with optimal mixture. The experimental results showed that the factor that most influenced compressive strength was the amount of CBWP as a cement substitute. The amount of CWA had the least effect on compressive strength. Maximum compressive strength was reached when 100% CWA was used as a coarse aggregate. The compressive strength of concrete containing CWA and CBWP decreased after 7 days but increased again after 28 days. Moreover, the use of CWA and CBWP improved the chloride ion permeability and sulphate resistance of the concrete compared to the control concrete. Meanwhile, the concrete containing CWA and CBWP had lower abrasion resistance than the reference concrete.

The Effect of Palm Oil Fuel Ash as Cement Additive on High-Strength Concrete

Palm oil production is one of the essential economies of Malaysia. Unfortunately, the by-product of this industry, a massive volume of palm oil fuel ash (POFA), may negatively impact the environment and human health. Hence, this study hypothesized that to reduce environmental or health hazards of the POFA, it could be reused as an additive or replacement in concrete. However, the idea of using the POFA has been chiefly applied to standard-concrete grades, but the use of high-strength concrete in structures is increasing worldwide, including in Malaysia. Hence this paper presents the experiment of the effect of POFA as an additive ranging between 0% and 15% to produce high-strength concrete with good workability. The tests conducted were the compression and slump tests. The specimen used in the compression tests were 100 mm concrete cubes tested in 3, 7, 14, and 28 days. It was found that the inclusion of 5% POFA as addictive to cement in concrete produced the highest compressive strength, 84.12 MPa, on the 28th day of testing. It was also found that its workability was as good as the control concrete. Thus, the utilization of POFA could be considered an environmental-friendly cement additive to be used as supplemental cementitious material to produce workable high-strength concrete.

Effects of using autoclaved aerated concrete block debris as lightweight aggregate on internal curing of concrete

This investigation was carried out to evaluate the effects of using autoclaved aerated concrete (AAC) block debris as lightweight aggregate (LWA) on internal curing of concrete. The volumetric changes during the early period of curing leads to early shrinkage before to the concrete hardening. The formation of internal cracks due to the shrinkage had evidenced the strength and durability problems in concrete during later stage. The higher absorption capacity of LWA has been acted as internal water stored reservoir in concrete and facilitate the supply of water for internal curing to promote the additional hydration. The internal curing effect of pre-wetted AAC debris as LWA on mechanical properties and absorption behaviour of concrete was deliberated as novelty and the investigation was carried out using three different cement contents such as 340 kg/m3, 380 kg/m3 and 420 kg/m3. The granite coarse aggregate was replaced by 10%, 20% and 40% using AAC block debris of the same size by volume. The density reduction of concrete was determined after the addition of LWC. It was found that the AAC block debris can help in increasing the slump value of concrete and enhancing the mechanical properties and the absorption behaviour of concrete on par with control concrete.

MECHANICAL BEHAVIOR OF CONCRETE WITH RECYCLED AGGREGATES AND EXPANDED POLYSTYRENE, FOCUSED ON PREFABRICATED PANELS

The urgent need to reduce the use of natural resources and energy consumption by the construction industry, as well as provide a solution to the accumulation of residues and waste generated in the construction sector, to clean up the environment, is of concern to scientists and researchers around the world. The aim of this study is to evaluate the viability of concrete with low resistance requirements, intended to be used in non-load-bearing prefabricated panels, in which the natural coarse aggregate has been replaced by recycled coarse aggregate in different percentages (25%, 50%, 75% and 100%), incorporating in all dosages, one third of the replacement, by expanded polystyrene. To do this, their mechanical and physical properties have been studied: compressive strength, flexural, diametral compression tensile, absorption, durability and density. The recycled coarse aggregates (brick masonry, concrete blocks and reinforced concrete structural elements) were obtained through a selective process of the waste generated in demolition works in the city of Guayaquil (Ecuador). The results show that as the percentage of rubble is reduced, the compressive strength and other mechanical properties increase, as well as its density, approaching more and more to that of the control concrete. The behavior of the best mixture, with 25% replacement with coarse recycled aggregates and expanded polystyrene, meets the structural requirements of a prefabricated wall panel, in addition to reducing the environmental impact generated by the use of natural aggregates.

Study of the Use of Dredged Sand as An Alternative to Beach Sand and Coastal Dunes for Coastal Preservation

The need for construction sand needs to increase due to the increase in population. The use of dunes and coastal sand disfigures shorelines and the consequences are alarming. It is therefore necessary to consider replacing these resources with other more ecological ones. Hence, it is the purpose of this article. In this paper, we study the correct formulation of concrete using dredged sand, respecting the standards, and analyze the impact of this new material on the physical and mechanical characteristics of concrete. This article aims to evaluate the effects of 9 formulations, used as substitutes for ordinary sand, on the physico-chemical and mechanical properties. The experimental results have shown that the dredged sand affects the properties of the concrete, but respecting the standards in force. This mode of incorporation also has an environmental advantage over the substitution of concrete for dredged sand, as it reduces the disfigurement of the coasts. The paper studies dredge sands from two regions namely Azemour and Mehdia. The dredging sand partially or totally replaces the dredging sand. Subsequently, it was necessary to test several formulations with different cement dosages before arriving at the formulations which are exposed in this study. The results in the fresh state (consistency test) and in the hardened state (mechanical resistance) have shown that this substitution is possible, and consequently we can use the dredged sands in concretes and in mortars. It is true that the study shows a reduction in resistance compared to a control concrete, but these reductions still remain in accordance with the Moroccan regulatory specifications.

Permeability study of water-proofing admixture and fly ash incorporated concrete using standard and own built test

One of the most important factors influencing concrete's age is its permeability. Many commercially available water-proofing chemicals claim to be helpful in water-proofing concrete while improving other attributes such as compressive strength, modulus of rupture, durability, and density. Furthermore, the mineral admixtures also improve concrete's mechanical and durability properties. DIN 1048 (Part 5), EN 12390 – 8, and IS 516 (Part 2): 2018 are standard codes for determining the water permeability of concrete. These codes lack information on the drying conditions of concrete samples between the pressure cycles of water permeability tests and leads to an inability to evaluate the effectiveness of using admixtures in concrete. Some more limitations of these codes are fixed duration of testing and bulky apparatus. In this study, the one- and four-cycle test with oven drying and the air-drying combination is carried out. The present study also focuses on evaluating the effectiveness of fly ash and waterproofing admixture as an additive in concrete to reduce the water permeability of concrete. Further, limitations of the previous test are taken into consideration, and the own built apparatus is developed. The own-built apparatus (water penetration test) works at the same pressure (5 kg/cm2) as the standard method. The own-built apparatus reduces the testing duration, and a more significant number of samples can be tested at a time compared to the traditional method. The results of water penetration depth for the different samples prepared at a common effective w/c ratio have given an insightful effect, as the concrete with similar strength was compared for permeability evaluation. Therefore, the present paper will enlighten the testing procedure, duration, and comparison of (0, 15, 25, and 35%) fly ash and (0.8 and 1.2%) waterproofing admixture concrete. The 15%, 25% and 35% fly ash incorporated concrete was found effective by 18 to 27% in reducing the penetration depth, whereas 0.8 and 1.2% water proofing admixture concrete reported 9 and 14% effective compared to control concrete. This study will help researchers to evaluate the comparative effectiveness of the ability of water-proofing and mineral admixtures in improving the permeability of the concrete and ultimately enhancing the durability of the concrete structure.

Bimbingan Teknis Kompetensi Manajemen Proyek Untuk Kompetensi Tambahan Calon Lulusan Universitas Iqra Buru

A construction project is one of the activities in which the results of the work are affected by the productivity of the workforce. Activities in construction projects are interrelated, so that if one activity is hampered it will hinder other activities in the field. Likewise construction activities are complex jobs and require more attention in their implementation. The elements that are part of the construction are cost, quality, and time in which there are also resources that must be controlled, such as work and materials. Based on this, it is necessary to have technical guidance for prospective civil engineering graduates to prepare them so that they are better prepared and able to enter the world of construction work later. Based on this, the Ministry of PUPR, the Director General of Construction Development, Jayapura Region VII Construction Services Center, and Iqra University, work together to carry out technical assistance activities in the Auditorium Room of Iqra Buru University, Namlea Regency. This activity lasted for 3 days. There were several materials presented, namely Project Management, K3, Quality Control and Precast Concrete. The activity participants consisted of more than 30 students, the majority of whom were final students who were doing their thesis and were about to graduate. This activity is carried out with lectures, giving assignments and questions and answers. This is done so that students are more focused on listening to the material and activities that are taking place.

Impact strength and mechanical properties of high strength concrete containing PET waste fiber

This study presents results of tests done on workability, mechanical properties, first cracking impact and ultimate load impact of high strength concrete (HSC) contained polyethylene terephthalate (PET) waste fiber. Different PET fibers with regard the length (10 mm, 20 and 40 mm) were added to concrete by 0.50, 0.75, 1.00, 1.25 and 1.50% (by volume). Density, ultrasonic pulse velocity, compressive strength, splitting tensile strength, flexural strength, first crack impact (N1) and ultimate load impact (N2) tests were conducted on sixteen HSC mixes. Results showed a slight change in ultrasonic pulse velocity, while addition of PET fiber with 10 mm, 20 mm and 40 mm length reduced compressive strength by a maximum value of 15.74, 14.37 and 10.28% respectively compared to control concrete. Regardless to the fiber length and fraction volume, fiber content improves splitting tensile and flexural strengths by a maximum of 63.3% and 24.7% respectively. Striking results were recorded against impact strength property, in which improvement in N1 recorded up to 300% and N2 up to 833% depending on fiber length and fraction volume. It is concluded that PET waste fiber can improve important properties of HSC and it is recommended to be added to concrete by up to 1.5% by volume. Regression analysis was made to develop equations for calculating N1 and N2, and these properties were found to depend essentially on compressive strength of plain concrete and PET fiber parameters.

Surface Modified Synthetic Plastic Aggregate for Concrete – Experimental and Analytical Studies

In order to reduce the plastic waste accumulation, and also to decrease consumption volume of natural resources for concrete production, in this paper, an attempt is made to produce novel lightweight coarse aggregate using PET based plastic waste. Use of plastic aggregate normally reduces the strength of concrete primarily due to smoother surface and poor bonding with adjacent cement matrix. Towards improving the bonding characteristics with cement matrix, different surface treatment procedures employing dispersion of sand and ceramic waste particles were tried. Experimental study consisted of using different percentages of plastic aggregate as partial replacement for conventional coarse aggregate. The mechanical properties of concrete such as workability, density, compressive strength and flexural-tensile strength were determined. Correlations studies to predict the concrete strength based on percentage of replacement, and equation relating compressive and flexural-tensile strengths of the concrete were also conducted. The studies indicated that it is possible to improve the bonding property of plastic aggregate for achieving strength and integrity similar to that of control concrete.