Applied Mechanics and Materials Vols. 754-755

Abstract: This study investigates the behavior of in-filled materials of profiled steel sheeting dry board (PSSDB) floor system. Two tests were conducted, namely, push-out test to know the connection stiffness and bending test on the PSSDB panel under the influence of different in-filled materials. Result of the push-out test shows that the connection stiffness of the geopolymer concrete-filled PSSDB is 331% higher than that of PSSDB that is filled with normal concrete. This connection stiffness contributed to the reduction of deflection value of 21% in the middle of the midspan for full-board geopolymer concrete in-filled panel bending test. This phenomenon triggered the increase of interaction within the composite system, making the panel that is filled with the geopolymer concrete 25% stronger than the normal concrete–filled panel.

Abstract: Discovering about sustainability, construction sector should be a part of participant in utilizing waste materials for the benefits of the industry. The idea of converting waste materials into some application can contribute to sustainability and greening the earth. Apart from that, research must be done to promote the waste material into economic and useful construction material. A concept of going green must be adopted rather than just thinking of the rapid construction as the whole project aim. This paper promotes sugarcane bagasse as an additive for construction material in 3 ways which are on concrete strength improver, a concrete retarder and composite brick. The sugarcane bagasse were blended and mixed with 30MPa concrete with certain ratio and tested for compressive, flexural, water absorption and penetration. From the tests, it shows that the sugarcane bagasse gives a positive impact to concrete. Therefore, the usage of sugarcane bagasse can be considered as a concept of utilizing waste material for sustainable approach.

Abstract: In the normal practice in the reinforced concrete design, the main reinforcement steel bar and links was used to fabricate the concrete structure. However new materials such as steel fiber has been introduced as the reinforcement to the reinforced concrete structure [1]. Nowadays, the application of fiber in concrete increase slightly as an engineering material demands. Fibers have distinctive of geometry, size and material. The characteristics and properties of fiber influence the properties concrete. Steel, glass and synthetic fibers were used in concrete in 1960s because of the difficulty to handle the asbestos fiber [2].

Abstract: Geopolymer is a well-known material names by Davidovit’s since 1970’s. The other names of geopolymer is alkali-activated cement, geocement, alkali-bonded ceramic, inorganic polymer concrete, and hydroceramic. In a simple explanation, the termed ‘geopolymers’ comes when the inorganic polymeric material synthesized in a manner similar to thermosetting organic polymers. The development and contribution of geopolymer to the industries are moving stage by stage until today. Since a decades, performance of Geopolymer has been evaluated and tested by researchers in many field. The result published showed the unique bonding between aluminosilicate and alkali solution produce high compressive strength, low shrinkage, resistance toward acid, resistance to fire and etc. Advance research showed the application of Geopolymer in civil engineering works (including structures and geotechnical) also giving a good strength result. To that extend, this paper try to review performances of geopolymer application in geotechnical fields.

Abstract: In this study, four types of Waste Paper Sludge Ash (WPSA) were explored for use as Supplementary Cementitious Materials (SCM) in binary system. The WPSA use varies in particle size range and surface area however similar in chemical composition. At first stage, Ordinary Portland Cement (OPC) was replaced by WPSA at 5% mass to mass basis as blended cement. Four size of WPSA was prepared which are unsieve, retained at 63μm, retained at 45μm and pan. WPSA blended cement (WPSABC) was introduced from the four size of WPSA that prepared earlier. Water to cement ratio selected was 0.50 and it keep constant at all type of blended cement. When compared with the control mix, result shows that hydration kinetics is affected by the particle size of WPSA. Pan WPSA has slightly higher peak of hydration kinetics and compressive strength of blended cement. At second stage, Pan WPSA was selected to undergo the further investigation on its performance. Pan WPSABC were prepared at replacement level of 5%, 10%, 15% and 20%, mass to mass basis. Same method and w/c ratio was used and compared with control mix. From the result, it is found that the peak for rate of heat evolution of Pan WPSABC occur earlier and slightly lower as compared to OPC. Pan WPSA also achieved it optimum strength at 5% replacement level which is more than control mix.

Abstract: We live in an era where people should be more aware of pollution and its consequences. The present paper reveals a way protecting the environment while producing high quality concrete. What make this type of concrete environmentally friendly are the recycled aggregates in the concrete composition amongst with eliminating the ecological impact by saving large amounts of natural aggregates resources. Recycling concrete comes with many other advantages that lead to waste reduction, economy in waste transportation and storage taxes, which are becoming increasingly expensive. This research is based on mix design and experimental tests carried out on C20/25 strength class concrete with uncontaminated leftover concrete aggregates (LCAgg). It reveals favorable results in order to militate for recycled concrete aggregate uses in regular concrete strength classes respectively for common structural elements, mainly for slabs. River sand (0/4 mm) and coarse aggregates (4/8 mm and 8/16 mm): natural sources or recycled concrete type-alternatively used in several mixes-were utilized in concrete mixes.

Abstract: This paper presents the results of using ground dune sand (GDS) and ground granulated blast furnace slag (slag) as high volume cement replacement materials. In this study, plain and four blended mixtures were fabricated and cured under normal and autoclave conditions. For the blended mixtures, 40% GDS by weight of the total binder materials and different percentages of slag (15%, 30% and 45%) were incorporated as partial cement replacement materials. The effect of curing conditions (normal and autoclave) on the compressive strength of prepared mixtures was studied. The results showed that, for the autoclave cured mixture, up to 85% of cement can be replaced by GDS and slag without significant drop in the compressive strength. Microstructure analyses using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) were carried out to examine the microscale changes of the hydrated mixtures. The SEM revealed the formation of thin plate-like calcium silicate hydrate and compacted microstructure of autoclave cured mixture. XRD showed the elimination of calcium hydroxide and existence of residual crystalline silica of all blended mixtures.

Abstract: This study is conducted to determine the effect of four variables on compressive strength of geopolymer concretes. These four variables are binder/aggregate, Alkalinene/fly ash, effect of superplasticizer (SP) addition and curing system. The compressive strength is important mechanical properties for construction material. Taguchi experimental design method is used to compile the concrete composition of geopolymer to achieve the maximum compressive strength. Specimens concrete used is a cylinder with 100 mm diameter and 200 mm height. Compressive strength test is performed at 28 day using SNI 03-6825-2002, Indonesian National Standard. This study concludes that the chloride environment has a beneficial effect on the compressive strength of the concrete. In addition, the Alkalinene/fly ash ratio and binder/aggregate give a significant effect on the compressive strength of geopolymer concretes.

Abstract: This paper describes the effect of alkaline activator ratio (Na₂SiO₃/NaOH) to mechanical properties of geopolymer concrete. The mechanical properties of geopolymer concrete were assessed by setting time, split tensile strength and porosity. Fly ash was used as a cement substitute, and trass used as filler. While, Natrium hydroxide (NaOH) and Sodium Silicate (Na₂SiO₃) was applied as alkaline activator. In this study, NaOH concentration eight and ten molar with an alkaline activator ratio Na₂SiO₃/ NaOH by mass: 0.5, 1, 1.5, 2 and 2.5 were used. The test result showed that setting time, porosity and split tensile strength of geopolymer concrete were hardly influenced by NaOH concentration and the alkaline activator ratio. The alkaline activator ratio of Na₂SiO₃/NaOH has an optimum value at 2 and 2.5. Test result showed that the fastest setting time was 25 minute, the highest amount of closed porosity was 9.035 % and the highest split tensile strength was 2.86 MPa.

Abstract: Disposal of alum sludge (AS) in such an economical and environmental friendly way is a major challenge that water treatment plants around the globe had to deal with. AS cannot be dumped into landfills as it contains heavy metals which are harmful to the environment. In this study, alum sludge is utilised as partial replacements (0, 5 and 10%) of natural granite coarse aggregate (by mass) to form a lightweight concrete. The water/cement ratio is 0.65. The water absorption of the alum sludge is 22.06%. The slump, density, compressive strength and split tensile strength of the lightweight alum sludge aggregate concrete (LASAC) reduce as the AS aggregate content increase. The density of the 10% AS aggregate concrete is 2185.3 kg/m³. The compressive strength reduced from 25.6 MPa to 16.7 MPa and 14.2 MPa at 0, 5 and 10% replacement of AS aggregate respectively. The 2.18 MPa tensile strength of the control concrete reduced to 1.53 MPa at 10% replacement of AS aggregate. But as for the flexural strength, it increases from 5.42 MPa for the control up to 5.55 MPa and 5.63 MPa for 5 and 10% replacement of AS aggregate respectively. Results show that strength of alum sludge lightweight aggregate concrete is better than lightweight crumb tyre aggregate concrete and is at par with oil palm coconut shell aggregate concrete.