Investigation of green foamed concrete incorporating palm oil fuel ash and eggshell ash as partial cement replacement

The tendency of concrete to absorb heat, high thermal conductivity and self-weight due to its high density, and its extensive use has given rise to Urban Heat Island (UHI). Therefore, this study was carried out to provide a solution to these limitations by developing innovative lightweight green foamed concrete (GFC) of 1800 kg/m3 density incorporating Palm Oil Fuel Ash (POFA) ranging from 20% to 35% and Eggshell Ash (ESA) from 5% to 15% as partial cement replacement. The effect of partial replacement on the workability was determined by J-ring test, mechanical properties such as, compressive and tensile strengths as well as modulus of elasticity and thermal performance of GFC was determined by thermal conductivity and surface temperature. Based upon the results, it was observed that the combined utilization of POFA and ESA reduced the workability slightly but enhanced the mechanical properties of GFC such that it can be used for structural applications. It was also observed that 25P5E, a total 30% cement replacement, was the optimum mix at which the maximum compressive and higher tensile strength, though up to 40% cement replacement can be done without any loss in strength. With the addition of POFA, the colour of specimens became blackish, thus due to albedo effect, these samples recorded higher surface temperature, though the surface temperature reduced slightly with the increment of ESA content. The inclusion of POFA and ESA in GFC reduced the thermal conductivity value. The combined utilization of POFA and ESA in the development of GFC contributes not only to reduction of dependency on cement for manufacturing of concrete but also towards the development of sustainable buildings which reduce the use of natural resources while at the same time provide beneficial mean for utilization of waste materials instead of disposing in landfills which causes scarcity of land and environmental issues

A Review on Emerging Cementitious Materials, Reactivity Evaluation and Treatment Methods

Alternative to traditional concrete, sustainable concrete reduces cement content, waste management issues, and CO2 emissions. To achieve sustainable concrete, waste materials can be used as supplementary cementitious materials (SCMs) to partially replace cement. Fly ash, ground-granulated blast furnace slag, and silica fume have been heavily studied as SCMs. However, due to the retirement of coal-fired power plants and switching to renewable energy, existing SCMs are losing their dominance. With SCMs becoming more widely accepted as partial cement substitutes, there is fear that the current supply will not meet future demand. As a result, researchers have been looking for alternative SCMs. The circular economy can be achieved by reusing non-hazardous construction and demolition materials, timber, and metal/steel production waste as SCMs. This article discusses emerging SCMs, reactivity evaluation methods, their limitations, and treatment methods that may improve reactivity. Emerging SCMs can replace existing SCMs in quantity, but their supply to cement factories and low reactivity due to stable crystallinity hinders their use. Among treatment methods, particle size reduction effectively enhances reactivity; however, very fine SCM may increase the overall water demand due to the large surface area. Decades-old reactivity evaluation methods have relatively weak correlations and thus misreport the reactivity of SCMs. Newer R3 models, such as calorimetry and bound water, give the best correlations (R ≥ 0.85) for 28-day relative strength and better performance. Additionally, more concrete testing with emerging SCMs under different durability and environmental protection conditions is required and life cycle assessments are needed to determine their regional environmental impact

Most Common Factors Causing Cost Overrun with its Mitigation Measure for Pakistan Construction Industry

Cost overrun is known as the leading challenge for stakeholders of the construction sector. Like most countries, Pakistan also facing this challenge for the last few decades. Literature review was conducted and managed to identify 34 factors which contributed to cost overrun in the construction industry. These factors were used as the main content in designing the questionnaire. Respondents were required to rate these factors based on 4-ponits Likert scale on the degree of commonly occurred. Survey was carried out involved 130 stakeholders of the construction sector to determine main factors of the overrun. Data was collected, analysed statistically using the average index method and found 10 most commonly occurred of cost overrun factors for Pakistan construction industry are financial crisis faced by the client; mistakes in making proper estimation; faults in drawing; delay in getting approval from the client; poor planning by client; incompetency of contractor; poor supervision of the consultant; delay in payment to the contractor; communication gap between parties and natural disaster. These factors were further explained together with its mitigation measure. The findings of this study can help to Pakistani construction community in controlling the cost overrun for their construction projects

Thermo‑mechanical properties of various densities of foamed concrete incorporating polypropylene fibres

Concrete has been extensively used in the development of urban infrastructure works. However, it has the tendency to absorb solar radiations, and these radiations are released back into the air in the form of heat energy. Dense concentration of infrastructures releases more heat, causing urban heat island (UHI) effect in which the ambient temperature of the urban areas rises slightly than the surrounding areas. Tropical countries which have a hot climate throughout the year are more affected by the UHI effect. Therefore, thermal insulating materials need to be introduced in the field of concrete construction. Foamed concrete, which has air voids in its matrix, is a potential thermal insulating material. But due to reduced density, it, however, achieves lower strength. Polypropylene (PP) fibres are used to reinforce the foamed concrete and improve its compressive and tensile strengths. In this study, three different densities, 1400, 1600 and 1800 kg/m3, were cast, and 0.8% PP fibres were added. The thermo-mechanical properties were investigated in terms of thermal conductivity, surface temperature, compressive and tensile strengths with and without the addition of PP fibres. Based on the findings, the addition of PP fibres gained more strength and reduced thermal conductivity in the lower densities of foamed concrete. In contrast, it had an opposite impact on 1800 kg/m3 density. The addition of PP fibres also indicated that it could reduce the surface temperature of higher-density foamed concrete compared to lower densities

Chemical and fresh state properties of foamed concrete incorporating palm oil fuel ash and eggshell ash as cement replacement

Malaysia faces three major environmental problems, out of which solid waste and management is one of them. Palm Oil Fuel Ash (POFA) and eggshells are two agro-food waste materials which are produced in enormous quantities in Malaysia. Due to the characteristics possessed by eggshells and POFA, these waste materials can potentially be utilized in the production as cement replacement, reducing the use of cement which is one of the major production of Carbon Dioxide (CO2) gas emissions. This study was conducted to determine the chemical and fresh state properties of foamed concrete incorporating POFA and eggshell ash (ESA) as cement replacement. Based upon the results, it was observed that the increase in usage amount of POFA and ESA as cement replacement, the workability of foamed concrete reduced without blocking. For the chemical analysis result shows the POFA which had high amount of silicon dioxide and ESA having large amount of calcium oxide were compatible and could be used together as cement replacement. The use of ESA and POFA as cement replacement to reduce the cement consumption with various percentage of ESA (0% - 15%) and POFA (20% - 35%) in 1800 kg/m3 density of foamed concret

Effect of river indus sand on concrete tensile strength

In the development of Pakistan construction industry, the utilization of River Indus sand in concrete as fine aggregate has expanded tremendously. The aim of this research is to study the effect of Indus River sand on the tensile strength of various grades of concrete when it is utilized as fine aggregate. Concrete Samples of M15, M20 and M25 grade concrete were cured for 7, 14, 21 and 28 days. Based on the results, it is found that concrete became less workable when Indus river sand was utilized. It is recorded that tensile strength of concrete is decreased from 5% up to 20% in comparison with hill sand. The results were derived from various concrete grades

Preliminary Study on the Mechanical Activation and High‐Temperature Treatment of Saponite‐Containing Tailings Generated during Kimberlite Ore Dressing

This study investigates transformations of a pre-mechanically activated saponite-containing material with subsequent high-temperature treatment. The thermogravimetric analysis confirmed that the mechanical activation of saponite leads to the destruction of its layered structure, accompanied by the release of silicon dioxide and magnesium oxide in free form. The values of surface activity for mechanically activated saponite-containing material are also calculated. It is shown that when mechanically activated saponite-containing material is mixed with water, minerals of the serpentine group are formed, and further high-temperature treatment leads to the formation of minerals of the olivine group. It is experimentally shown that high-temperature treatment leads to the creation of a more durable structure of the saponite-containing material. This is due to decreased porosity and pore size, and sorption of moisture from the environment is also reduced. The study showed that saponite-containing waste materials can be effectively treated to create composite materials based on magnesia binders. Thus, with this method, the waste is effectively recycled into various green building material and can be used as supplementary cementitious material or fine aggregate replacement in concrete

Utilization of palm oil fuel ash and eggshell powder as partial cement replacement - a review

The increase in population leads to increase in construction of houses and other buildings to accommodate these people. The extensive use of concrete for constructional purposes leads to release of Carbon Dioxide (CO2) gas into the atmosphere which adds to the already increased global warming. The increase in urbanization has also lead to increased generation of waste materials. These waste materials are by-products, which are disposed in landfills causing environmental and health issues. The utilization of agricultural wastes as cement substitute is a great alternative for reducing the use and production of cement, which contributes to 5% to 7% of global CO2 emissions alone. Palm Oil Fuel Ash (POFA) Eggshells are two major agricultural wastes, which are generated in abundance in Malaysia. This paper reviews the combined utilization of Eggshells Powder (ESP) and POFA as potential partial cement replacement material and development of bio-concrete, which may help in reducing the environmental issues that are caused by the agricultural by-products. They have been used successfully but individually in concrete. The pozzolanic activity triggered by POFA requires Calcium Hydroxide which cement provides to a limit. Eggshells when grinded into Eggshells Powder (ESP) are rich in calcium oxide and can provide the required calcium hydride and enhance the pozzolanic reactio

Mechanical Properties of Concrete Containing River Indus Sand and Recyclable Concrete Aggregate

In Pakistan construction Industry, concrete construction is cheaper than the other construction methods with respect to that construction materials demand rises. The 75% volume of total concrete fill with aggregate which contributes to decrease the natural aggregate resources day by day. The best solution for this problem is to utilize River Indus sand and recyclable concrete aggregate as fine and coarse aggregate respectively. In this research the River Indus sand and recyclable coarse aggregate were fully replaced with normal aggregates. The aim of this study was to examine the flexural and tensile performance of concrete containing the River Indus sand and recyclable concrete aggregate. The physical properties were also examined which include the sieve analysis and chemical composition of River Indus sand. The M15, M20 and M25 grade were analyzed at 7, 14, 21 and 28 days water curing. The results define that, flexural strength was reduced from 5% to 15% compared to normal aggregate whereas tensile was decreased from 1% to 1.8% at 28 days water curing