Water permeability of foamed concrete

This study focused on the compressive strength and water permeability of foamed concrete. Two types of foamed concrete mix with density 1500 kg/m3 and 1700 >5 kg/m were experimented Timber industrial ash (HA) were used as the partial cement replacement material, replacing 10% of Ordinary Portland cement (OPC) in the mix design. The test cubes were 150 mm X 150 mm X150 mm size subjected to wet-cured and air cured for up to 28 days. The density, compressive strength development and water permeability of the TIA foamed concrete were determined to compare with the control mix (without TIA). The test method adopted based on DIN 1048 was used to determine the water permeability of foamed concrete at 28 days. Compressive strength was determined at 3 days, 7 days and 28 days. It was found that the air-cured specimens achieved a higher compressive strength and lower water permeability compared with the wet-cured specimens. Foamed concrete with 10% HA reduced the water permeability with a lower compressive strength at 28 days. The preliminary result indicated that HA has potential to reduce the water permeability of foamed concret

INFLUENCE OF SULFATE AND CHLORIDE ON THE MECHANICAL PROPERTIES OF FIRED CLAY MASONRY WALL

This paper presents the influence of aggressive environment on the mechanical properties of masonry systems. The investigation involved the measurement of strength and modulus of elasticity of single leaf brick masonry wall which were built from fired clay bricks in conjunction with designation (iii) mortar with proportions of 1: 1: 6 (OPC: lime: sand). After being constructed, the specimens were cured under polythene sheet for 14 days in a controlled environment room with 80 ± 5% relative humidity and temperature of 25 ± 2ºC. The specimens were then exposed to the solution containing sodium sulfate and sodium chloride. The strength and modulus of elasticity of the brickworks were determined at the ages of 28, 56 and 180 days. The strength and modulus of elasticity of the brickworks, unbonded bricks, and mortar prisms were determined at the ages of 28, 56 and 180 days to quantify the contribution of bricks and mortar on the deformation of the masonry walls. As a result, fired clay brickwork is not durable and deteriorate in the environment containing sodium sulfate but durable in sodium chloride. The deterioration of the brickwork clearly influenced by the deterioration of mortar joint. The present of sodium chloride also retarding the attack of sodium sulphate.  &nbsp

Engineering properties and microstructure of brickwork under aggressive environment

The influence of aggressive environmental exposures on the mechanical properties and performance of masonry systems has been investigated. The investigation involved the measurement of moisture movement, strength and modulus of elasticity of single leaf masonry walls which were built from fired-clay and calcium silicate bricks in conjunction with designation (iii) mortar with proportions of 1: 1: 6 (OPC: lime: sand). After being constructed, the masonry walls were cured under polythene sheet for 14 days in a controlled environment room with temperature of 20±5ºC and 80±5% relative humidity. They were then exposed to sodium sulphate, sodium chloride and sodium sulphate-sodium chloride solutions at different concentrations of 5, 10 and 15%. The strength and elastic modulus of the brick walls were determined at the ages of 28, 56, and 180 days. At the same time, the moisture movement of the brick walls was monitored up to 210 days. The moisture movement, strength and modulus of elasticity were also measured on the unbonded bricks and mortar prism so that the contribution of brick types and mortar on the deformation of the masonry walls could be quantified. In addition, the properties of companion control walls, brick units and mortar were also assessed so that the effects of the aggressive exposure conditions could be quantified. XRF analysis was also carried out to determine the actual elements in the masonry materials before being exposed to soluble salts. XRD, SEM and EDX analysis were conducted after 180 days to observe the compounds developed after the exposure the soluble salts. As a result, after the period of exposure to the soluble salt conditions, large expansion and reduction in strength as well as elasticity of masonry wall were observed in particular for the case of sulphate exposures. These are mainly associated with the formation of ettringite crystals in the mortar, inducing expansion, cracking and disintegration of the mortar which led to the disintegration of the masonry walls. The formation of thenardite was observed in the fired-clay and calcium silicate brick due the exposure to sulphate, whereas halite formation was observed for the case of calcium silicate brick and mortar, due the exposure to chloride, but they did not cause any significant effect on the masonry walls. The composite model underestimated the modulus of elasticity and moisture movement of masonry wall which were exposed to the aggressive environments. Both the fired-clay and calcium silicate masonry walls exhibited better performance in chloride environment than in sulphate exposure and sulphate – chloride exposure due to the formation of expansive ettringite crystals

Properties of concrete containing recycled PET bottles as sand replacement

The modern lifestyle along with the new technologies have contributed the increasing of waste materials production. Plastic is one of the waste materials which is non-disposal and non-biodegradable material that can remain on earth without degradation. The world produces nearly 150 million tonnes of plastics per year, which is nearly 4.8 tonnes per second and a per capita production of 25 kg/year [1]. The Malaysian Plastic Industry (2012), reported that Malaysia is one of the largest plastics producers in Asia [2]. In Malaysia, extensive consumption of PET bottle is one of the contribution to the increasing growth of plastic waste disposed in landfills. Reutilization of PET wastes in concrete technology is one of the innovative solution for reduce the materials cost and solve some of the plastics waste problems .

Proceedings of the Sustainable Concrete Materials and Structures in Construction 2020

Seminar on Sustainable Concrete Materials and Structures in Concrete Construction 2020 was held virtually for the first time on 24 August 2020. This event was organized by the Faculty of Civil Engineering and Built Environment (FKAAB), Universiti Tun Hussein Onn Malaysia (UTHM) in collaboration with Concrete Society of Malaysia (CSM) and Civil Engineering and Built Environment Postgraduate Society, FKAAB (CiBPS). The theme of this seminar is Toward Sustainable Green Concrete. This seminar marks the first collaboration between these three organizations

Mechanical properties of the concrete containing porcelain waste as sand

The demand of concrete have been increases on a daily bases which consume a lot of natural resource such as sand and gravel, there is an immediate need for finding suitable alternative which can be used to replace sand partially with another materials with high propor-tion . Ceramic waste is one of the strongest research areas that include the activity of replacement in all the sides of construction materi-als. This research aims to improve the performance of concrete using ceramic waste, and demonstrate the performance of mechanical properties to the concrete with partial replacement of sand by using waste porcelain. For these, we analyzed the mechanical properties of the concrete such as compressive strength, split tensile and flexural strength, the specimen were measured based on 10% ,20% ,30% ,40%, and 50% weight ratio of replace sand with waste porcelain at different time under water for 7 days , 28 days , 60 days . The optimum consideration were given to mechanical properties of the concrete, at different amount of ceramic waste as sand

Effects of Coal Bottom Ash as Cementitious Material on Compressive Strength and Chloride Permeability of Concrete

Coal Bottom Ash (CBA) is the waste material produced by coal-based power plants, particularly in Malaysia around 1.7 million tons of CBA was produced annually, which is major environmental concern. Therefore, the use of CBA as a partial replacement of cement in concrete is a possible solution for that pollution; this approach also creates a new corridor in the field of concrete production. However, this study aims to evaluate the effects of CBA as cementitious material on the concrete properties. This study incorporated 10% CBA as a cement replacement by weight method in concrete. However, concrete samples were prepared with and without CBA and immersed in water for 7, 28, 56 and 90 days. Next, the performances of concrete with and without CBA were evaluated in terms of workability, compressive strength, and rapid chloride permeability test. It was found that due to presence of CBA in concrete, workability reduces; no substantial growth in compressive strength at the early ages but substantial rise in strength was noticed after 56 days. Almost 4.7% higher strength was recorded than the control specimens at 90 days. Besides that, concrete containing CBA has lower chloride penetration as compared to the control specimen, which shows its better durability performance. It can be concluded that CBA has an enormous potential to be utilized as a cementitious material in durable concrete production

Mechanical properties and thermal behaviour of two-stage concrete containing palm oil fuel ash

Two-stage concrete (TSC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Over the decades, the application of supplementary cementing materials in conventional concrete has become widespread, and this trend is expected to continue in TSC as well. Palm oil fuel ash (POFA) is one of the ashes which has been recognized as a good pozzolanic material. This paper presents the experimental results on the performance behaviour of POFA in developing physical and mechanical properties of two-stage concrete. Four concrete mixes namely, TSC with 100% OPC as a control, and TSC with 10, 20 and 30% POFA were cast, and the temperature growth due to heat of hydration and heat transfer in the mixes was recorded. It has been found that POFA significantly reduced the temperature rise in two-stage aggregate concrete and delayed the transfer of heat to the mass of concrete. The compressive and tensile strengths, however, increased with the replacement of up to 20% POFA. The results obtained and the observation made in this study suggest that the substitution of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great importance

Characterisation of Ground Coal Bottom Ash With Different Grinding Times

The physical and chemical composition of Ground Coal Bottom Ash (GCBA) exposed to varying grinding periods is discussed in this article. CBA was pulverised for 20 hours, 30 hours, and 40 hours in a ball mill machine. Particle Size Analyzer (PSA) and X-ray Fluorescence (XRF) instrument were used to characterise GCBA. According to the results of the tests, GCBA with a grinding duration of 40 hours generates the largest percentage of the finest particle (50-1000 nm) at 4%, the specific surface area is 13528.18 cm2/cm3, and the specific gravity (SG) is 2.54. According to the XRF results, there are no significant variations in the chemical compositions of the CBA with varying grinding periods. At 20, 30, and 40 hours grinding time, the primary oxide element for SiO2 is 51.5%, 53.8%, and 52.3%, while Al2O3 is 14.3%, 15.1%, and 14.6%, and Fe2O3 is 5.08%, 5.27%, and 5.07% respectively. The sum of three primary oxide constituents surpasses the 70% ASTM C618 limit for pozzolanic material Class F fly ash

Performance of plastic wastes in fiber-reinforced concrete beams

Synthetic plastics are typically discarded, thus causing environmental pollution. Plastic wastes are recycled as fiber in concrete to solve this problem. In this study, synthetic fibers in a concrete matrix were investigated through compressive strength, splitting tensile, fracture energy, and flexural beam tests. The results show that an increase in fiber content improves the tensile strength of the concrete matrix. A high fiber content results in a substantial amount of fibers crossing a fractured section, thereby activating failure resistance mechanisms. Ring-shaped fibers, which are mainly designed to activate fiber yielding instead of fiber pullout, are better than irregularly shaped polyethylene terephthalate and waste wire fibers. Incorporating plastic fibers into concrete does not significantly change the failure mode of reinforced concrete beams compared to that of normal concrete beams. However, the first crack load presented improved results. The reinforced concrete containing ring-shaped plastic fibers with a width of 10 mm (RPET-10) exhibited remarkable results during the first crack load with an increment of 32.3%. It can be concluded that ring-shaped PET waste produces fiber concrete with a performance comparable to that of commercial synthetic fibers