Nur Hafizah A. Khalid

RHIZOPHORA APICULATA AS ECO-FRIENDLY INHIBITOR AGAINST MILD STEEL CORROSION IN 1 M HCL

The inhibitive characteristics of aqueous extracts from mangrove (Rhizophora apiculata) bark and leaf on the corrosion of mild steel (MS) coupon in 1 M HCl were examined by means of the gravimetric measurement (weight loss), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The MS surface morphologie were investigated using field emission scanning electron microscopy (FESEM) with Energy Dispersive X-Ray Analysis (EDX) at 120h in the presence and absence of green inhibitors in corrosive medium. Respective inhibition efficiencies of 68.1% and 59.0% were obtained when exposed to 10% v/v Rhizophora apiculata solution for 72h. Examination of the adsorption behavior of the solutions indicated the Langmuir isotherm model as being the most likely relevant adsorption mechanism. In addition, polarization measurements showed that both bark and leaves extract inhibitors act via mixed type inhibition.

Sustainability, Eco-Point and Engineering Performance of Different Workability OPC Fly-Ash Mortar Mixes

This study investigates the engineering performance and CO2 footprint of mortar mixers by replacing Portland cement with 10%, 20%, 40% and 60% fly ash, a common industrial waste material. Samples of self-compacting mortar (SCM) were prepared with four different water/binder ratios and varying dosages of superplasticizer to give three ranges of workability, i.e., normal, high and self-compacting mortar mix. The engineering performance was assessed in term of compressive strength after designated curing periods for all mixes. CO2 footprint was the environmental impact indicator of each production stage. The optimum mix obtained was at 10% replacement rate for all mixes. Total production emission reduced by 56% when the fly ash replacement rate increased from 0% to 60% (maximum). This is translated to a reduction of 80% in eco-points (assuming that the energy consumption rate of production with 0% fly ash is at 100%). Such re-utilization is encouraged since it is able to reduce possible soil toxicity due to sulfur leaching by 5% to 27% and landfill area by 15% to 91% on average.

A Review of the Mechanical Properties of Concrete Containing Biofillers

Sustainable construction is a rapidly increasing research area. Investigators of all backgrounds are using industrial and agro wastes to replace Portland cement in concrete to reduce greenhouse emissions and the corresponding decline in general health. Many types of wastes have been used as cement replacements in concrete including: fly ash, slag and rice husk ash in addition to others. This study investigates the possibility of producing a sustainable approach to construction through the partial replacement of concrete using biofillers. This will be achieved by studying the physical and mechanical properties of two widely available biological wastes in Malaysia; eggshell and palm oil fuel ash (POFA). The mechanical properties tests that were studied and compared are the compression, tensile and flexural tests.

Experimental Study of Splitting Tensile Strength of Polymer Resin Grout with Fly Ash

Polymer resin grout can be used as bonding material for grouted sleeve connections This paper presents the experimental results on the effectiveness of fly ash as micro filler to the splitting tensile strength of polymer grout. In addition, the cement grout that is usually used as bonding material had been tested for comparison. Eleven proportions, of fly ash as the filler and polymer as binder, were tested with the binder to filler volume ratios of 1:1 and 1:1.5. The test results revealed that fly ash can be used as a micro-filler material to partially replace ordinary river sand in polymer resin grout. The splitting tensile strength of the polymer grout increases with the increase of fly ash contents. However, for higher level of fly ash of more than 22%, the splitting tensile strength deteriorated. For binder: filler ratio of 1:1, the optimum fly ash content of 22% gave the maximum splitting strength of 17.62 MPa, which can be considered acceptable for producing grout with high strength bonding material.