Effects of by-product materials (POFA and PFA) as partial cement replacement on concretetowards corrosion reisitance

The utilization of pulverized fuel ash (PFA) and palm oil fuel ash (POFA) in producing a new construction material is seen as one of the ways to reduce the quantity of these wastes or by-products disposed at landfills. These materials are identified as pozzolana which are used as a partial replacement of the Portland cement. This step enables building materials to be managed in a sustainable manner, thereby reducing pollutions and landfill areas in the future. PFA is a by-product material produced from the burning of coal in electric power plants, while, POFA is the residue obtained by burning husks or fibers, and palm kernel shells used as biomass in palm oil mills. This thesis presents an experimental study of the engineering properties and durability of concrete based cement blended using different byproduct materials namely POFA and PFA in tackling the reinforcement corrosion problem in concrete. Seven types of mixes were prepared, which consisted of a control mix and other mixes consisting of 10, 20 and 30 percent of POFA and PFA as a partial cement replacement for each by-product. The influence of POFA and PFA replacement level and mixing constituents on the compressive strength of concrete have been investigated under different curing regimes namely water, control room, wet-dry cycle and outdoor up to one year concrete age. Studies on the durability aspect of the mix towards its porosity, microstructure, crystallization product and corrosion resistance are also investigated. The result shows the performance of concrete with 20 percent of POFA and PFA produces a comparable compressive strength with the control mix with water curing regime. The constant presence of moisture is significant for strength development of POFA and PFA concrete mixes since the pozzolanic reaction is only able to take place in the later age, after calcium hydroxide is available from the hydration process in the presence of moisture. Other than that, the utilization of POFA and PFA in concrete improves concrete porosity by improving the microstructure due to the densification of concrete by reducing voids inside the concrete. At the same time, POFA and PFA concrete mixes demonstrate a higher resistance to chloride ion penetrations than the control mix. Due to these reasons, the POFA and PFA concrete mixes have exhibited a good resistance towards corrosion after undergoing accelerated corrosion tests. In this test, the control concrete cracked and failed after two days as compared to POFA and PFA concrete, which took a longer period that are 14 and 21 days to crack due to the corrosion of steel reinforcements. Finally, the study shows that the utilization of PFA as a cement replacement material produces a better performance than POFA in all aspects of concrete properties due to its chemical compound and fineness. As a conclusion, the use of PFA and POFA at the level of 20 percent as the replacement of Portland cement is optimum in concrete and does not affect the compressive strength but also improves the durability of concrete, especially against corrosion resistance. The use and recycling of these materials not only reduces environmental problems and concrete production cost, it can also produce concrete with better properties and performance

Case study of Block 1, Highland Towers Condominium collapsed in Taman Hillview, Ulu Klang, Selangor, Malaysia on 11th December 1993

Landslide has become the primary focus in slope engineering as the case increases. Most landslides are resulted from an unknown confluence, and most occur on slopes created by humanity. Highland Towers were built between 1976 and 1979, and its occupants were primarily first and middle-class people. There is a steep hill behind the three blocks. The main draws here are the natural scenery and panoramic vista of Kuala Lumpur. This case study investigates what factors led to Block 1, Highland Towers condominium’s collapse on 11th December 1993 at 1.35 p.m. using reliability analysis approaches and human fault impact factors. The Block 1 collapse is caused by an unstable pile foundation. The engineers incorrectly estimated the horizontal load design, causing surcharge loads to be created by the downhill forward movement when the rotating retrogressive slide happens. However, several precautions may be taken to protect the building structures from landslide. It is common knowledge that structural reliability analysis yields failure probabilities that are not considered for human faults. Inadequate drainage, collapse of retaining wall, and rail piling foundation are all plausible explanations for this landslide initiation. Thus, combining structural and human reliability analysis are recommended to mitigate landslide, including slope hazards

Properties of concrete and structural behaviour of reinforced concrete beam containing shredded waste paper as an additive

This research uses WP to investigate the effect of two types of Shredded Waste Paper (SWP) comprising Shredded Copier Waste Paper (SCPWP) and Shredded Cardboard Waste Paper (SCBWP) as additives on the properties of concrete and the structural behaviour of Reinforced Concrete Beam (RCB). The slump, compressive, flexural, and splitting tensile strengths increase by 4–13% for 5–10% addition of SCPWP and decrease by 16–23% for 15% addition of SCPWP compared to 0% addition. For SCBWP, the slump, compressive, flexural and splitting tensile strengths increase by 10–23% for 5–10% addition and decrease by 15–21% for 15% addition compared to 0% addition. 15% of SCPWP and SCBWP addition records the highest effect in water absorption and efflorescence, showing 11% and 10.28% increases with 15% addition of SCBWP and SCPWP. Scanning electron microscope (SEM) analysis reveals that the crack is repaired, and the presence of calcium hydroxide (Ca(OH)2) and calcium–silicate–hydrate (C–S–H) links enhances the concrete strength. The addition of 10% SCPWP and 10% SCBWP in the concrete mixtures improves the structural behaviour of RCB with stirrup spacing (SS) = 100 mm (full), 150 mm and 200 mm (reduced) by increasing the load and reducing the deflection. Apart from that, the concrete bending and shear strains also increase by 44.17% and 34.9%. The failure mode of the RCB changes from shear to bending. This study indicates that SCPWP and SCBWP can be used as additives in concrete at 5% and 10%, and 10% for RCB with significant strength and structural improvement

Experimental investigation and finite element analysis of reinforced concrete beams strengthened by fibre reinforced polymer composite materials : A review

As a composite material, fibre reinforced polymer (FRP) has many uses. Incorporating FRP composite material enhances the reinforced concrete beams’ (RCB) performance, properties and behaviour as external reinforcement. A summary of how different FRP influences the RCB properties should be studied. This review paper discusses the use of FRP to reinforce RCB and briefly describes the topic. Previous experimental studies and finite element analysis (FEA) results showed that RCB constructed with FRP significantly improved the axial load, load-deflection, ultimate load, crack propagation, stress-strain distribution, and failure mode of RCB. Since this FRP composite material has superior strength, force, mounting and anchoring properties, it can be used as an alternate exterior reinforcement in RCB. The structural behaviour and performance of RCB can be enhanced by utilising FRP composite material in civil and structural engineering, especially in building construction projects

A narrative review on strengthening of reinforced concrete beams using carbon fibre reinforced polymer composite material through experimental investigation and numerical modelling

Carbon fibre reinforced polymer (CFRP) composite material has many benefits. The reinforced concrete beams (RCB) structural behaviour is improved due to the usage of CFRP composite material as external reinforcement. The effects of CFRP on various features are also essential to be summarised. This review paper concisely summarises the strengthening of RCB using CFRP. The flexure, stiffness, young modulus, load–deflection, ultimate load capacity, load-axial, fracture pattern, stress–strain distribution, and failure mechanism of RCB made with CFRP were significantly improved based on previous relevant experimental investigation and numerical modelling results. This CFRP composite material can be used as external reinforcement for RCB because of its overqualified strength capability, force, load, corrosion resistance, adhesive, and anchoring properties. Using CFRP composite material in civil and structural engineering can improve the RCB's structural behaviour and performance, particularly in the construction industry

Load-Strain Behaviour of Shredded Waste Paper Reinforced Concrete Beam

Cement, sand, coarse aggregate, water and reinforcing bar are the materials to make a reinforced concrete beam. The waste paper has been dumped as waste and causes environmental pollution behind mill or landfill. The industry paper wastage for every year is increasing gradually. More spaces are being needed for landfills, uses energy loss of natural resources and increase of expenditure and various types of pollutions. Utilizing waste paper as an addition in concrete and reinforced concrete beam productions will reduce environmental pollutions. This research investigates the load-strain behaviour of reinforced concrete beam containing shredded waste paper using 10% copier and 10% cardboard waste paper as additions in the concrete mixture to the concrete shear strain and concrete bending strain of reinforced concrete beam. There are three types of beam shear reinforcements with stirrup spacing (SS)=100 mm, 150 mm, and 200 mm. All specimens are subjected to air curing at 28 days. The result of concrete bending and shear strains are higher by 10% shredded copier waste paper (SCPWP) and 10% shredded cardboard waste paper (SCBWP) with reducing shear reinforcements (SS=200 mm) and (SS=150 mm) compared to full shear reinforcement (SS=100 mm). This research shows that 10% SCPWP and 10% SCBWP improves the concrete bending and shear strains with reducing reinforcements. Furthermore, the results also show that 10% SCBWP has higher concrete bending and shear strains than 10% SCPWP for full and reduce shear reinforcements. This study indicates that shredded copier and cardboard waste paper can be used as additional materials in reinforced concrete beam production

Effect of Curing Regime on Compressive Strength of Aerated Concrete Containing Palm Oil Fuel Ash as Partial Sand Replacement

Issues on preservation of natural river sand from being used excessively in concrete industry has led to the efforts of utilizing palm oil fuel ash, a by-product from palm oil industry as partial sand replacement in production of aerated concrete. This paper reports the effect of curing regime on compressive strength development of aerated concrete containing palm oil fuel ash as partial cement replacement. Two types of mixes were used in this experimental work namely plain aerated concrete acting as control specimen and aerated concrete containing 30% palm oil fuel ash as partial sand replacement. Concrete cubes were subjected to different types of curing namely initial water curing for 7 days followed by air curing, water curing and air curing until the testing date. The compressive strength test was conducted in accordance to BS EN 12390-3 at 7, 14, 28 and 90 days. Application of water curing is the most suitable method to be applied to ensure better strength development in aerated concrete containing POFA as partial sand replacement. Continuous presence of moisture promotes better hydration and pozzolanic reaction leading to formation of extra C-S-H gel making the concrete denser and exhibit higher compressive strength

Study on Durability Performance of Concrete Containing Laterite Aggregates

This paper addresses the durability performance of concrete containing laterite aggregate against corrosion, acid attack and carbonation. Two types of mixes were used, that is plain concrete (0% laterite aggregate) and another one, produced by integrating 20% of laterite aggregate as partial coarse aggregate replacement.  The corrosion resistance test was conducted by immersing the 28 days water cured specimens in sodium chloride for 1, 7 and 15 days. The steel bars were then connected to the data logger to determine the corrosion potential of each specimen. The acid resistance of specimens were investigated by immersing it in hydrochloric acid solution and the mass of cubes were measured at every 100 hour until 1800 hour. Carbonation depth was determined by spraying phenolphthalein indicator on broken surface of prism with curing age up to 1 year. The corrosion potential of both types of concrete rose as experimental period become longer. The acid resistance results show the difference in total mass loss of laterite concrete and control specimen is less than 5%. Carbonation results of the specimens are also close to each other. Utilization of 20% laterite aggregate as partial coarse aggregate replacement influences the resistance of concrete upon corrosion effect, acid attack and carbonation

Effect of incorporation POFA in cement mortar and desired benefits: a review

Palm oil fuel ash (POFA) is a by-product waste material more economical and environmentally friendly, resulted from production palm oil products. Lack of enough information on the advantages of POFA in the concrete production in various proportions was the main cause to select this work. This paper presents the advantages of POFA as a partial cement replacement in concrete production. This study recommends that researchers and academics should show more experimental works in order to illustrate the desired benefits from POFA as cement replacement, thus mitigate of environmental impacts

Investigation on the properties of mortar containing palm oil fuel ash and seashell powder as partial cement replacement

The concept of utilizing various types of wastes, such as agricultural dumps and marine by-products, as a partial replacement of cement has gained a great interest to develop eco-friendly and economical mortars for sustainable construction. This study aims to evaluate the feasibility of using palm oil fuel ash (POFA), an agro-industrial waste by-product from palm oil mills and seashell powder (SSP) derived from seashells, a marine waste material partial replacement of cement in mortars. The water to binder (w/b) ratio of 0.49 and the sand to binder (s/b) ratio of 2.54 with 0% to 30% of ordinary portland cement (OPC) by weight was replaced with POFA and SSP, and the resulting mortar samples were tested for mechanical properties and durability in this study. The compressive strength, flexural strength, water absorption, and flow table tests were performed in this study for different percentages of POFA and SSP after 7, 28, and 130 days. The results showed that the 30% POFA incorporated mortars achieved the highest compressive strength (35.12N/mm2), flexural strength (4.06N/mm2), high density with less water absorption (4.79%) after 130 days of curing and the high strength mortar with less water flow (22.2cm) during casting. Also, it found that the 25% POFA and 5% SSP incorporated mortars attained acceptable results as supplementary cementing material. This study suggests that the POFA and SSP incorporated mortars could be used in concrete for sustainable development of construction through the efficient valorization of waste materials