Hashim Abdul Razak

Performance appraisal of industrial waste incineration bottom ash as controlled low-strength material

Controlled low-strength material (CLSM) is slurry made by mixing sand, cement, ash, and water. It is primarily used as a replacement for soil and structural fillings. This paper presents the findings of a preliminary investigation carried out on the performance of industrial waste incineration bottom ash as CLSM. CLSM mixes were designed using industrial waste incineration bottom ash, and cement. Tests for density, setting time, bleed, and compressive strength on cubes under various curing conditions, corrosivity, and leaching of heavy metals and salts were carried out on the CLSM mixtures, and the results discussed. Compressive strength for the designed CLSM mixtures ranged from 0.1 to 1.7 MPa. It is shown that the variations in curing conditions have less influence on the compressive strength of CLSM at high values of water to cement ratio (w/c), but low values of w/c influences the strength of CLSM. The CLSM produced does not exhibit corrosive characters as evidenced by pH. Leaching of heavy metals and salts is higher in bleed than in leachate collected from hardened CLSM. Cement reduces the leaching of Boron in bleed. It is concluded that there is good potential for the use of industrial waste incineration bottom ash in CLSM.

Effect of kaolin addition on the performance of controlled low-strength material using industrial waste incineration bottom ash

Incineration of industrial waste produces large quantities of bottom ash which are normally sent to secured landfill, but is not a sustainable solution. Use of bottom ash in engineering applications will contribute to sustainability and generate revenue. One way of using the industrial waste incineration bottom ash is in controlled low-strength material (CLSM). Use of bottom ash in CLSM has problems related to bleeding and excessive strength development and so an additive has to be used to control bleeding and strength development. The main objective of this research is to study the effect of kaolin addition on the performance of CLSM made using industrial waste incineration bottom ash. CLSM mixes were made with bottom ash, cement, and refined kaolin. Various tests were performed on the CLSM in fresh and hardened states including compressive strength, water absorption, California bearing ratio (CBR) and the tests for concentration of leachable substances on the bleed and leachate. The compressive strength of CLSM tested ranged from 0.11 to 9.86 MPa. CBR values ranged from 6 to 46, and water absorption values from 12 to 36%. It was shown that the addition of kaolin delayed the initial setting time of CLSM mixtures, reduced bleeding, lowered the compressive strength, and increased the values of water absorption, sorption, and initial surface absorption. The CLSM tested did not have corrosivity. It was shown that the hardened CLSM was non hazardous, and the addition of kaolin increased the concentration of heavy metals and salts in the bleed and leachate.

Combined modal parameters-based index for damage identification in a beamlike structure: theoretical development and verification

A new index for detecting the damage severity in structural elements by combining modal parameters is proposed in this study. The index is based on the combined effect of both the natural frequencies and mode shapes when a change in stiffness of the structural element occurs. In order to demonstrate the significance and capability of this new algorithm, the magnitude of damage was calculated from a finite element model of a beam-like structure model and comparisons with previous algorithms were carried out. The new index called Combined Parameter Index (CPI) compares the factor of reduction in stiffness according to reduction in natural frequencies and also the factor of reduction in stiffness according to change in mode shape. Various damage levels starting from reduction in stiffness of 1% were adopted to validate the sensitivity of the new index to detect the damage severity at various deterioration levels. Mid-span and quarter-span damage positions were adopted to verify the capability of the new damage index to detect the damage severity at various locations. Moreover, damage in support condition was investigated in order to ascertain that the new damage index can also identify support damage cases. The results indicate that the new index has better ability and higher sensitivity to determine the severity of the damage due to stiffness changes in the element or support. In addition, the CPI exhibits sensitivity to detect lower level of damage occurring at earlier stage by having the ability to detect a damage of 1% reduction in the structural element stiffness or elastic bearing stiffness.

Feasibility Studies of Palm Oil Mill Waste Aggregates for the Construction Industry

The agricultural industry in Malaysia has grown rapidly over the years. Palm oil clinker (POC) is a byproduct obtained from the palm oil industry. Its lightweight properties allows for its utilization as an aggregate, while in powder form as a filler material in concrete. POC specimens obtained throughout each state in Malaysia were investigated to evaluate the physical, chemical, and microstructure characteristics. Variations between each state were determined and their possible contributory factors were assessed. POC were incorporated as a replacement material for aggregates and their engineering characteristics were ascertained. Almost 7% of density was reduced with the introduction of POC as aggregates. A sustainability assessment was made through greenhouse gas emission (GHG) and cost factor analyses to determine the contribution of the addition of POC to the construction industry. Addition of POC helps to lower the GHG emission by 9.6% compared to control specimens. By channeling this waste into the construction industry, an efficient waste-management system can be promoted; thus, creating a cleaner environment. This study is also expected to offer some guides and directions for upcoming research works on the incorporation of POC.

Utilization of Palm Oil Clinker as Cement Replacement Material

The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized.

Corrosivity and leaching behavior of controlled low-strength material (CLSM) made using bottom ash and quarry dust

This paper reports the corrosivity and leaching behavior of CLSM made using two different industrial wastes i.e. bottom ash from an incineration facility and quarry dust. The leachate samples were derived from fresh and hardened CLSM mixtures, and studied for leaching and electrical resistivity. The release of various contaminants and the consequent environmental impact caused by the contaminants were studied by the measurement of contaminants in the bleed, in the leachate at 28 days, and on the leachate derived from crushed block and whole block leaching done over a period of 126 days. Results indicated that the CLSM mixtures are non corrosive; diffusion was the leaching mechanism; and the contaminants were found to be moderate to low mobility.

A Comparative Study on Optimal Structural Dynamics Using Wavelet Functions

Wavelet solution techniques have become the focus of interest among researchers in different disciplines of science and technology. In this paper, implementation of two different wavelet basis functions has been comparatively considered for dynamic analysis of structures. For this aim, computational technique is developed by using free scale of simple Haar wavelet, initially. Later, complex and continuous Chebyshev wavelet basis functions are presented to improve the time history analysis of structures. Free-scaled Chebyshev coefficient matrix and operation of integration are derived to directly approximate displacements of the corresponding system. In addition, stability of responses has been investigated for the proposed algorithm of discrete Haar wavelet compared against continuous Chebyshev wavelet. To demonstrate the validity of the wavelet-based algorithms, aforesaid schemes have been extended to the linear and nonlinear structural dynamics. The effectiveness of free-scaled Chebyshev wavelet has been compared with simple Haar wavelet and two common integration methods. It is deduced that either indirect method proposed for discrete Haar wavelet or direct approach for continuous Chebyshev wavelet is unconditionally stable. Finally, it is concluded that numerical solution is highly benefited by the least computation time involved and high accuracy of response, particularly using low scale of complex Chebyshev wavelet.

An Improved Method of Parameter Identification and Damage Detection in Beam Structures under Flexural Vibration Using Wavelet Multi-Resolution Analysis

This paper reports on a two-step approach for optimally determining the location and severity of damage in beam structures under flexural vibration. The first step focuses on damage location detection. This is done by defining the damage index called relative wavelet packet entropy (RWPE). The damage severities of the model in terms of loss of stiffness are assessed in the second step using the inverse solution of equations of motion of a structural system in the wavelet domain. For this purpose, the connection coefficient of the scaling function to convert the equations of motion in the time domain into the wavelet domain is applied. Subsequently, the dominant components based on the relative energies of the wavelet packet transform (WPT) components of the acceleration responses are defined. To obtain the best estimation of the stiffness parameters of the model, the least squares error minimization is used iteratively over the dominant components. Then, the severity of the damage is evaluated by comparing the stiffness parameters of the identified model before and after the occurrence of damage. The numerical and experimental results demonstrate that the proposed method is robust and effective for the determination of damage location and accurate estimation of the loss in stiffness due to damage.

Indirect Time Integration Scheme for Dynamic Analysis of Space Structures Using Wavelet Functions

AbstractIn this paper, an indirect and numerical time integration approach is proposed for dynamic analysis of space structures by using comprehensive wavelet functions. For this purpose, the proposed scheme is implemented on the second-ordered differential equation of motion governing single-degree-of-freedom (SDOF) systems and subsequently for multi-degrees-of-freedom (MDOF) systems. In this way, two different types of free-scaled wavelet functions have been utilized, namely the simple Haar wavelet functions and the complex Chebyshev wavelet functions. Accordingly, for the proposed procedure, a simple formulation has been derived from the adaptive approximation of external loadings and responses by free-scaled wavelet functions. It is deduced that the proposed method lies on unconditionally stable scheme. From an optimization point of view, the error and computation time involved have been comparatively evaluated. Finally, it is demonstrated that the time history analysis of space structures is optimall...

Optimum dynamic analysis of 2D frames using free-scaled wavelet functions

This paper presents a wavelet-based scheme for dynamic analysis of 2-dimensional (2D) frames. In the proposed approach, free-scaled wavelet functions are developed for Multi-Degrees-of-Freedom (MDOF) structures, particularly, complex Chebyshev and simple Haar wavelets are implemented. A simple step-by-step and explicit algorithm is presented to calculate the time history response of 2D frames. The validity of the proposed procedure is demonstrated with two examples compared with several common numerical integration procedures such as family ofNewmark-β, Wilson-θ and central difference method. Finally, it is shown that dynamic analysis of 2D frames is optimally accomplished by lesser computational time and high accuracy of results.