Properties of concrete containing recycled PET bottles as sand replacement

The modern lifestyle along with the new technologies have contributed the increasing of waste materials production. Plastic is one of the waste materials which is non-disposal and non-biodegradable material that can remain on earth without degradation. The world produces nearly 150 million tonnes of plastics per year, which is nearly 4.8 tonnes per second and a per capita production of 25 kg/year [1]. The Malaysian Plastic Industry (2012), reported that Malaysia is one of the largest plastics producers in Asia [2]. In Malaysia, extensive consumption of PET bottle is one of the contribution to the increasing growth of plastic waste disposed in landfills. Reutilization of PET wastes in concrete technology is one of the innovative solution for reduce the materials cost and solve some of the plastics waste problems .

The impact resistance and mechanical properties of concrete reinforced with waste polypropylene carpet fibres

The utilization of waste materials is one of the fundamental issues of waste management strategies in many parts of the world. With the advances in cement and concrete technology, the use of waste materials in the concrete industry has developed gradually widespread because of technological, economic and ecological advantages. This paper presents the potential use of waste polypropylene carpet fibres, and highlights the impact resistance and mechanical properties of concrete with the fibres. Six volume fractions varying from 0 to 1.25% of 20-mm-long carpet fibres were used with ordinary Portland cement (OPC) concrete mixes. Another six mixes were made where OPC was replaced by 20% palm oil fuel ash (POFA) as supplementary cementing material. It has been found that the addition of polypropylene carpet fibre decreased the slump values and increased the VeBe time of fresh concrete. The inclusion of carpet fibre to either OPC or POFA concrete mixes did not improve the compressive strength at early ages. At later ages, however, the compressive strength of the mixtures containing POFA significantly increased and the obtained values were higher than that mixes with OPC alone. The positive interaction between carpet fibres and POFA leads to high tensile strength, flexural strengths and impact resistance, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. It is concluded that waste carpet fibres and palm oil fuel ash can be used as building materials in the construction of sustainable concrete

Evaluation of heat of hydration of concrete containing high volume palm oil fuel ash

Pozzolanic materials, either naturally occurring or artificially made, have long been in practice since the early civilization. In recent years, the utilisation of pozzolanic materials in concrete construction has become increasingly widespread, and this trend is expected to continue in the years ahead because of technological, economical and ecological advantages of the materials. One of the latest additions to the ash family is palm oil fuel ash, a waste material obtained on burning of palm oil husk and palm kernel shell as fuel in palm oil mill boilers, which has been identified as a good pozzolanic material. This paper highlights test results on the performance behaviour of high volume palm oil fuel ash (POFA) in reducing the heat of hydration in concrete. Four concrete mixes namely OPC concrete i.e. concrete with 100% OPC as control, and high volume concrete i.e. concrete with 50%, 60% and 70% POFA were prepared, and the temperature rise due to heat of hydration in all the mixes was recorded. It has been found that palm oil fuel ash significantly reduced the total temperature rise in concrete. The result obtained and the observation made clearly demonstrate that the high volume replacement of cement by palm oil fuel ash is advantageous, particularly for mass concrete where thermal cracking due to excessive heat rise is of great concern

Performance evaluation of concrete containing high volume palm oil fuel ash exposed to elevated temperature

The properties of concrete exposed to elevated temperature are of great importance in terms of structural stability and assessment of serviceability state of the structure. This paper presents the results of a study on the performance behaviour of concrete containing high volume palm oil fuel ash exposed to high temperature. Concrete samples were made where ordinary Portland cement was replaced by 50%, 60% and 70% palm oil fuel ash. The samples were thermally treated to elevated temperatures of 200, 400, 600 and 800 �C in an electric furnace for a period of 1 h after attaining the peak temperature. Specimens exposed to elevated temperature were cured in air and were tested for visual observation, change in weight, ultrasonic pulse velocity and residual compressive strength. It has been observed that higher the temperature, higher was the residual weight loss of concrete samples. Along with the loss of residual compressive strength, the ultrasonic pulse velocity of concrete was also reduced at elevated temperature. Data generated in this study was used to develop simple relationship for expressing residual compressive strength as a function of ultrasonic pulse velocity

Mechanical properties and thermal behaviour of two-stage concrete containing palm oil fuel ash

Two-stage concrete (TSC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Over the decades, the application of supplementary cementing materials in conventional concrete has become widespread, and this trend is expected to continue in TSC as well. Palm oil fuel ash (POFA) is one of the ashes which has been recognized as a good pozzolanic material. This paper presents the experimental results on the performance behaviour of POFA in developing physical and mechanical properties of two-stage concrete. Four concrete mixes namely, TSC with 100% OPC as a control, and TSC with 10, 20 and 30% POFA were cast, and the temperature growth due to heat of hydration and heat transfer in the mixes was recorded. It has been found that POFA significantly reduced the temperature rise in two-stage aggregate concrete and delayed the transfer of heat to the mass of concrete. The compressive and tensile strengths, however, increased with the replacement of up to 20% POFA. The results obtained and the observation made in this study suggest that the substitution of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great importance

Effect of cooling regime on the residual performance of high-volume palm oil fuel ash concrete exposed to high temperatures

This paper presents the experimental findings of a study on the effect of cooling method on the residual performance of concrete containing a high volume of palm oil fuel ash (POFA) exposed to high temperatures. In this study, concrete samples were made in which the ordinary Portland cement was replaced by 50%, 60% and 70% POFA. The test specimens were then thermally treated to elevated temperatures of 200, 400, 600 and 800 �C in an electric furnace for a period of 1 h. The specimens were cured by air cooling or water cooling and examined for ultrasonic pulse velocity and changes in weight and residual compressive strength. At higher temperatures, the reduction in the ultrasonic pulse velocity of concrete was higher for all of the mixes. Along with the loss of weight, the residual compressive strength of concrete was also reduced. Of the two regimes, the air-cooling system exhibited better performance in recovering the structural properties of concrete containing a high volume of POFA

Green concrete production incorporating waste carpet fiber and palm oil fuel ash

With the increasing amount of waste generation from various processes, there has been a growing interest in the utilization of waste in producing building materials to achieve potential benefits. This paper highlights the results of an experimental investigation on the performance of concrete incorporating waste carpet fiber (WCF) and palm oil fuel ash (POFA) as partial replacements of ordinary Portland cement (OPC). Six volume fractions varying from 0 to 1.25% of 20-mm-long carpet fiber were used with OPC concrete mixes. Another six mixes were made that replaced OPC with 20% POFA. The specimens were cured in water and tested for fresh and hardened state properties. The combination of WCF and POFA decreased the slump values and increased the VeBe time of fresh concrete. The addition of WCF to either OPC or POFA concrete mixes did not improve the compressive strength or modulus of elasticity. At 91 days, the compressive strength was in the range of 38.1e49.1 MPa. The positive interaction between WCF and POFA, however, leads to high tensile and flexural strengths, thereby increasing the concrete ductility with higher energy absorption and improved crack distribution. The maximum increases in tensile and flexural strengths compared to those of plain concrete were achieved by the addition of 0.5% carpet fiber at the age of 91 days. The ultrasonic pulse velocity (UPV) was examined and was classified as good quality concrete. The study showed that the use of waste carpet fiber and palm oil fuel ash in the production of sustainable green concrete is feasible both technically and environmentally

The role of expanding admixture in the development of strength of prepacked concrete

Prepacked concrete is a special type of concrete which is different from the normal concrete in a number of ways. In this concrete, the coarse aggregates are first placed into the formwork and subsequently cement-based grout, usually with admixtures, is injected to fill the spaces between the coarse aggregates. This paper highlights the influence of chemical admixture, particularly the effectiveness of expanding agent in the development of strength of prepacked concrete at different ages of 7, 28 and 90 days. Along with prepacked concrete, normal concrete specimens having same water-cement and aggregate-cement ratios were made and tested under the same condition to evaluate the comparative behavior of strength development. It has been found that the overall compressive strength of both types of concrete with superplasticiser were higher than in concrete without any admixture. Expanding admixture, however, had been shown to have excellent performance in developing both compressive and tensile strength, as it provided better contact through expansion as well as through reduction in water-cement ratio in the grout

Durability performance of green concrete composites containing waste carpet fibers and palm oil fuel ash

Cleaner production is a pressing concern of the 21st century. Waste materials resulting from different industrial processes requires proper management to ensure a cleaner environment. The use of recycled materials in new green concrete production is very attractive due to the low-cost related to the waste materials in addition to saving required space for landfill purposes and the development as well as improvement in the concrete properties. This paper focuses on the durability properties of green concrete composite, which comprised of waste polypropylene (PP) carpet fiber and palm oil fuel ash (POFA). Properties studied include slump and VeBe time of fresh concrete as well as water absorption, sorptivity, chloride penetration, carbonation, and drying shrinkage of hardened concrete. Carpet fiber of 20 mm in length and six volume fractions of 0e1.25% were used with ordinary Portland cement (OPC). Another six concrete mixes were cast whereby OPC was replaced by 20% POFA. It was observed that the combination of PP carpet fiber and POFA decreased the slump values and increased the VeBe time of the fresh concrete mixes. In addition, water absorption, sorptivity, chloride penetration, and carbonation depth of the concrete composite for both OPC and POFA content mixtures were reduced with the addition of carpet fiber, with volume fractions of up to 0.75%. The positive interaction between carpet fibers and POFA subsequently led to the lower drying shrinkage of the concrete composite. The influences of POFA on the durability performance of concrete was observed to be more significant at longer curing periods. The findings of the study demonstrated that there is a promising future for the use of waste carpet fibers as a fibrous material in the production of a green and durable concrete. Green concrete also minimizes solid wastes, improves air quality, and leads to sustainable cement and concrete industry

Two-Stage Concrete as a Sustainable Production

Two-stage concrete (TSC) is a sustainable concrete which is produced by forcing a flowable cement grout mixture through the voids of a skeletal mass made of compacted preplaced aggregates. From the technical and economic aspects, TSC is particularly useful for construction and repair of concrete structures especially foundations, underwater construction, nuclear reactors, concrete dams, heritage structures and in constructions with closely spaced reinforcement. TSC differs from ordinary concrete in that it contains a higher proportion of stone aggregate and the aggregate stays in point-to-point contact as placed. Thus, the mechanical characteristics of the TSC in failure conditions are distinctly different from ordinary concrete. This paper presents the results of experimental investigations conducted to evaluate the compressive, tensile strength and modulus of elasticity of TSC using grouts with different water-to-cement ratios and admixture contents. It was found that the modulus of elasticity and splitting tensile strength of TSC are equivalent or higher than that of conventional concrete at the same compressive strength. In this method of construction, the splitting tensile strength can be conservatively estimated using the American concrete institute (ACI) equation for conventional concrete