Abdul Aziz Abdul Samad

Incorporation of Sewage Sludge in Clay Brick and its Characterization

This study reports the use of sewage sludge generated from sewage treatment plant (STP) as raw material in a clay brick-making process. The physico-chemical and mineralogical characterization of the sewage sludge and clay were carried out in order to identify the major technological constraints and to define the sludge pretreatment requirements if necessary. Moreover, the effects on processing conditions and/or on changes of typical final characteristics are also evaluated. Bricks were produced with sewage sludge additions ranging from 10 to 40% by dry weight. The texture and finishing of the surface of sludge-amended clay bricks were rather poor. As for the physical and chemical properties, bricks with a sludge content of up to 40 wt.% were capable of meeting the relevant technical standards. However, bricks with more than 30 wt.% sludge addition are not recommended for use since they are brittle and easily broken even when handled gently. A tendency for a general degradation of brick properties with sludge additions was observed due to its refractory nature. Therefore, sludge bricks of this nature are only suitable for use as common bricks, which are normally not exposed to view, because of poor surface finishing.

Structural Behavior of Precast Lightweight Foam Concrete Sandwich Panel with Double Shear Truss Connectors under Flexural Load

This paper presents the structural behaviour of precast lightweight foam concrete sandwich panel (PFLP) under flexure, studied experimentally and theoretically. Four (4) full scale specimens with a double shear steel connector of 6 mm diameter and steel reinforcement of 9 mm diameter were cast and tested. The panel’s structural behavior was studied in the context of its ultimate flexure load, crack pattern, load-deflection profile, and efficiency of shear connectors. Results showed that the ultimate flexure load obtained from the experiment is influenced by the panel’s compressive strength and thickness. The crack pattern recorded in each panel showed the emergence of initial cracks at the midspan which later spread toward the left and right zones of the slab. The theoretical ultimate load for fully composite and noncomposite panels was obtained from the classical equations. All panel specimens were found to behave in a partially composite manner. Panels PLFP-3 and PLFP-4 with higher compressive strength and total thickness managed to obtain a higher degree of compositeness which is 30 and 32.6 percent, respectively.

Physiochemical, Biochemical, Minerals Content Analysis, and Antioxidant Potential of National and International Honeys in Pakistan

16 honey samples from Pakistan and two other countries were investigated for their physiochemical, biochemical, minerals, and antioxidant potential. Antioxidant activities of all honey samples were performed by using percentage inhibition of DPPH free radical, AEAC, and FRAP. 5-HMF and mineral contents were determined by HPLC and AAS, respectively. The obtained values of respective parameters, namely, pH, EC, TDS, total acidity, moisture, ash, color intensity, sugars, proline, and protein were in compliance with codex standard and recommendation of council directive by European Union. The total phenolics contents in acacia honey from Germany and jujube honey from Pakistan are similar to monofloral honey from Saudi Arabia and Yemen, respectively. The mineral contents in tested honey samples are comparable with honey from Brazil and Romania. Dark color honeys contained higher phenolic contents than light color ones and attributed to higher oxidation potential and have strong positive correlation with DPPH and FRAP.

Contribution of RHA granules as filler to improve the impact resistance of foamed concrete

Foamed concrete as aerated concrete widely used in range of constructions application, no exception to structure shield. As structure shield is important to resist on impact loading. Whilst, Rice Husk Ash (RHA) as agro-waste potentials as filler for foamed concrete. RHA that is produced by uncontrolled burning under 700oC during ± 6 hours obtain the granules contain the carbon and porous. The granules of RHA may fill the porous in matrix foamed concrete without remove the characteristic the foamed concrete its self-as aerated concrete. This investigation RHA has been used as a replacement for fine aggregate. Target density 1800 kg/m3 of foamed concrete both of with and without RHA have been produced to compare their strength and characteristic of impact resistance. SEM and EDS test has been conducted to determine microstructure and chemical composition of foamed concrete with RHA. The results showed that granules of RHA filled the porous and bonded with the denser part into matrix. The presence of granules of RHA has been changing the role of the air cell of porous in foamed concrete when it was subjected to impact loading. Also the granules of RHA give the foamed concrete denser without losing its characteristic of porous entirely.

Effect of Uncontrolled Burning Rice Husk Ash in Foamed Concrete

Recently, foamed concrete has become a popular construction material that can be used in wide range of constructions application. Whilst the Rice Husk Ash (RHA) as agro-waste is contain high amount of silicon dioxide. RHA is produced in significant amount every year from agriculture countries. RHA has potential as a material to produce foamed concrete. In this research RHA has been used as a replacement for fine aggregate which used in construction as ordinary concrete material. In this study, foamed concrete with target density 1400, 1600 and 1800 kg/m3 has been produced. The compressive strength of foamed concrete with RHA has been tested. Concrete with Ratio 1:3 of RHA/Sand has higher compressive strength than ratios 3:1 and 2:2 of RHA/sand for every density. XRD and XRF test has been used to determinate chemical composition and crystalline structure of RHA. The result showed that RHA is an amorphous material which amorphous is important thing to pozzolanic process when hydration of cement paste. SEM and EDS test has been conducted to determine microstructure and chemical composition on microstructure of RHA foamed concrete. Amorphous RHA incorporating cement paste produces pozzolanic reaction. It is reduces the porosity and width of interfacial zone in such a way the density is increase.

Investigation on Effects of Variables on Shear Capacity of Precracked RC T-Beams with Externally Bonded Bi-directional CFRP Discrete Strips

This study aims to investigate the shear performance of partially precracked Reinforced Concrete (RC) T-beams bonded externally with bi-directional Carbon Fiber Reinforced Polymer (CFRP) discrete strips. A series of twelve RC T-beams are fabricated with internal transverse steel reinforcement and subjected to four-point and three-point bending systems. The external CFRP reinforcement strips are applied on the web and soffit of the beam with two-component epoxy system. The parameters investigated in the experimental program included (i) longitudinal tensile reinforcement ratio, (ii) shear span to effective depth ratio, (iii) spacing, and (iv) orientation of discrete CFRP strips. The experimental results show that the bi-directional CFRP discrete strip reinforcement significantly increases the shear capacity between 18 and 54% over the control beams. It is found that the test variables have significantly influenced the shear capacity of the CFRP strengthened beams. This study also validates the obtained experimental results with different existing theoretical models.

Potential of RHA in Foamed Concrete Subjected to Dynamic Impact Loading

In relation to the conventional concrete then foamed concrete (FC) is weaker. Therefore FC was added by Rice Husk Ash (RHA) to alter the strength without eliminating its characteristic as aerated concrete. Actually function of RHA is substitute the sand partly. The strength of concrete affects to prevent the dynamic impact loading. However FC as aerated concrete can absorb energy impact by its porosity. Both of characteristics were presented in this investigation. SEM and EDS detected that pozzolanic reaction was done when FC was processing hydration of cement in admixture. The presence of RHA increased the strength of concrete owing to cement hydration process and pozzolanic reactivity of RHA. The result of impact loading on slab FC target displayed that FC with RHA was more shallow than without RHA. Beside of that local damage showed that FC with RHA denser and is not impression of fragments than FC without RHA.

Investigation on Energy Absorption of Slab Foamed Concrete Reinforced by Polypropylene Fibre Subjected to Impact Loading

Polypropylene Fibre (PF) as reinforcement has contributed to the intensity of Foamed Concrete (FC) slab when subjected to impact loading. The presence of PF in the admixture reduces the micro-porosity that generates the micro-crack of the slab. However, the fibrillation of PF in the admixture enhances the bonding mechanism system between PF and the FC matrix. The impact test conducted uses an instrumented drop-weight impact tower. Results show that FC without PF produces a distinct radial crack and clear fragments within the crater field unlike FC with PF. However, both slab materials did not generate spalling nor scabbing upon impact and the influence of porosity produces only local damage due to the mechanism of brittle crushing effect of porous walls. In this study, the energy absorption between FC with and without PF was investigated and from observation produces only minor differences. Results also verify that FC with PF did not loss its ability to absorb energy upon impact.

The Use of Recycled Aggregate in a Development of Reinforced Concrete Container as a Retaining Wall: Preliminary Study

Construction waste has been increasing due to fast development of construction industries. These wastes usually end up on landfill or to be left nearby construction site. This paper focuses on the potential use of recycled waste aggregate in a development of reinforced concrete rectangular container, RACC, as a solid waste storage. The filled container is intended to be used as a retaining structure at riverbanks to control erosion. The experimental programme include cube and cylindrical specimens tested to determine characteristic properties of recycle aggregate concrete (Pc, Pt, E). The characteristic properties obtained were used in designing the RACC to function as storage container and also as a retaining wall as referred to BS 8110 and BS 8007. Results showed that recycle aggregate concrete has relatively high compressive strength, tensile strength and modulus of elasticity. RACC size of 1.0 m x 1.0 m x 1.0 m with 150 mm thickness is found to be suitable and safe to be used both as container and retaining wall. This is proven by the maximum deflection and crack widths achieved which are lower than the allowable limit values.

Leaching Behaviour of Organic Materials in Reinforced Concrete Artificial Reef with RAC

This paper reports the leaching behaviour of pineapple skins incorporated in the artificial reef fabricated from recycle aggregate concrete. Pineapple skin was mixed with the concrete as added material which produce nutrients to attract fish habitat. Material test was conducted on the concrete reef specimens to determine its compressive strength. The nutrients dispersed were measured by using total phosphorus and nitrate test of the water sample collected from each of the artificial reef within the six days duration. Results showed the compression strength of the reef decreased with the increase of percentage pineapple skin used. However, it was found that the total phosphorus and nitrate leached from the reef increased gradually with time as the percentage of pineapple skin used increased.