Showing papers by "Arul Arulrajah published in 2016"
TL;DR: In this article, the authors investigated the carbon footprint of CCR and fly ash-based marine clay and found that CCR is an industrial byproduct obtained from acetylene gas production, high in Ca(OH)2 and was used as a green additive to improve strength of the FA based geopolymer binder.
205 citations
TL;DR: In this paper, a liquid alkaline activator comprising sodium silicate solution (Na 2 SiO 3 ) and sodium hydroxide (NaOH) was used for the alkali activation of the CCR-based geopolymers.
146 citations
TL;DR: In this article, the effects of alkali activator and curing time on unconfined compressive strength (UCS) and microstructural characteristics of marginal lateritic soil (LS) stabilised with high calcium fly ash (FA)-based geopolymer, which is novel in the field of pavement geotechnics was also evaluated through laboratory evaluation tests.
Abstract: Marginal soils are traditional stabilised with Portland Cement (PC) when used as a pavement material. The production of PC is however an energy-intensive process and emits a large amount of greenhouse gas into the atmosphere. Geopolymer is an environmentally friendly ‘green’ binder commonly used in building applications but rarely used in pavement applications. The application of geopolymer to marginal soil stabilisation is an innovative approach given the increasing scarcity of virgin quarry materials in many countries. This research investigates the effects of alkali activator and curing time on unconfined compressive strength (UCS) and microstructural characteristics of marginal lateritic soil (LS) stabilised with high calcium fly ash (FA)-based geopolymer, which is novel in the field of pavement geotechnics. The viability of using this stabilised material as a bound pavement material was also evaluated through laboratory evaluation tests. A liquid alkali activator was a mixture of sodium silicate (Na2...
139 citations
TL;DR: In this paper, the strength development of RAP-FA geopolymer as a road construction material was investigated via Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) analyses.
130 citations
TL;DR: In this paper, highway embankment construction has been identified as an avenue to consume huge amounts of calcium carbide residue (CCR), which is an industrial byproduct, stockpiles of which are rapidly accumulating worldwide.
Abstract: Calcium carbide residue (CCR) is an industrial by-product, stockpiles of which are rapidly accumulating worldwide. Highway embankment construction has been identified as an avenue to consume huge q...
126 citations
TL;DR: In this paper, a field trial was conducted to ascertain the viability of using calcium carbide residue (CCR) stabilized clayey soil as a highway subgrade course material, which was selected as a control binder in the field trial for comparison purposes.
103 citations
TL;DR: In this article, the behavior of C&D materials when stabilized with geopolymers was evaluated and a different alkaline activator solution to pozzolanic binder ratio was tested.
Abstract: The use of recycled construction and demolition (C&D) materials in unbound and cement stabilized pavement base/subbase applications has generated growing interest in recent years. C&D materials consisting of crushed brick (CB), recycled crushed aggregate (RCA), and reclaimed asphalt pavement (RAP) have been investigated in unbound and cement stabilized pavement base/subbase applications. However, the high carbon footprint of using cement for pavement base/subbase stabilization has led to this research to seek alternative low-carbon binders. This study evaluates the behavior of C&D materials when stabilized with geopolymers. Fly ash (FA) and ground granulated blast furnace slag (S) were used as pozzolanic binders and a different alkaline activator solution to pozzolanic binder ratio was tested. A maximum of 4% of dry weight of soil was used for geopolymer stabilization of the C&D materials. The binders used were either 4% FA, 2% FA+ 2% S, or 4% S. The geotechnical engineering and strength propertie...
99 citations
TL;DR: In this article, a study on durability against w-d cycles, an important parameter for service life design of the sustainable masonry units, is investigated in order to evaluate the viability of using two waste materials, water treatment sludge (WTS) and fly ash (FA), for developing sustainable units in terms of strength.
Abstract: The viability of using two waste materials, water treatment sludge (WTS) and fly ash (FA), for developing sustainable masonry units has been previously investigated in terms of strength but the important aspect of durability against wetting–drying (w–d) cycles has yet to be studied. A study on durability against w–d cycles, an important parameter for service life design of the sustainable masonry units, is investigated in this paper. The liquid alkaline activator (L) was a mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), and a high calcium fly ash (FA) was used as a precursor. The results of cyclic w–d test indicate that the WTS–FA geopolymer manufactured with an optimum ingredient (L:FA=1.6, Na2SiO3:NaOH=90∶10) and at an optimum heat condition of 85°C for 72 h can be used as durable bearing masonry units; i.e., the compressive strength is greater than 12 MPa after 12 w–d cycles. For this optimum ingredient, the w–d cycle strength, qu(w−d) at heat temperatures between 65 and 95°C ...
95 citations
TL;DR: TCLP results demonstrated that there is no environmental risk for both R AP-FA blends and RAP-FA geopolymers in road construction and the outcomes from this research will promote the move toward increased applications of recycled materials in a sustainable manner in roadConstruction.
95 citations
TL;DR: In this article, a low carbon concept for manufacturing masonry units using RG-FA geopolymers was explored by applying low curing temperature of 50°C and a low curing period of just 3-7 days.
91 citations
TL;DR: In this paper, the authors evaluated the possibility of combining a highly organic waste (CG) with industrial wastes (S and FA) into a sustainable subgrade construction material by a geopolymerization process.
TL;DR: In this paper, the strength development of coffee grounds when used as a geopolymer stabilized embankment structural fill material aiming to better understand the stability of highly organic material was studied.
Abstract: The drinking of coffee forms a deep-rooted pastime in many communities worldwide. However, the culture of coffee drinking generates vast quantities of organic waste that ends up in landfills. Current research trends are inclined towards recycling of waste materials into alternative construction materials, hence the need to research sustainable uses for spent coffee grounds. Coffee grounds (CG) are highly organic with a very high percentage of biodegradable material. The objective of this research was to study the strength development of CG when used as a geopolymer stabilized embankment structural fill material aiming for a better understanding of geopolymer stabilization of highly organic material. Fly ash (FA), being a silica and alumina rich material, was used as a precursor. A liquid alkaline activator, L, being a sodium hydroxide-sodium silicate solution was used for alkali activation of FA in the CG-FA geopolymer. Factors found to affect strength development of the CG-FA geopolymer were: (1)...
TL;DR: In this paper, the authors evaluated fly ash (FA) as an alternative low-carbon binder for the stabilization of Recycled Concrete Aggregates (RCA) as a road construction material.
TL;DR: In this article, the authors investigated enhancing the behavior of large volume underground concrete structures with expansive agents, and the results of concrete specimen in laboratory curing condition indicate that the restrained expansion ratio of concrete with expansive agent rapidly increases within the first 3 days.
TL;DR: In this article, the effect of low and high content of fly ash-based geopolymers on strength development of recycled materials is investigated for the first time, and the results of unconfined compressive strength and resilient modulus testing indicate that alkali-activated fly ash is a viable binder for the stabilization of C&D aggregates.
Abstract: The reuse of recycled construction and demolition (C&D) aggregates in civil engineering infrastructure applications has been considered a low-carbon solution to replace conventional pavement aggregates. Evaluating the strength development mechanism and interparticle flow of forces in geopolymer stabilized C&D aggregates will provide fundamental understanding of the behavior of stabilized C&D aggregates. The C&D aggregates studied are reclaimed asphalt pavement (RAP), recycled concrete aggregate (RCA), and crushed brick (CB). The performance of alkali-activated fly ash (geopolymer) on the stabilization of C&D aggregates, under different curing conditions and sample preparation methods were studied. Fly ash was used as the precursor for the alkali-activated binder that was used to stabilize the C&D aggregates. The effect of low and high content of fly ash–based geopolymers on strength development of recycled materials is investigated for the first time. Sodium silicate and sodium hydroxide were used, with different ratios, to intensify the alkaline environment for fly ash to accelerate the strength development of the mixture. The effect of static and dynamic compaction on the density and strength development was investigated for both low-content fly ash and high-content fly ash. Temperature treatment of geopolymer stabilized C&D aggregates up to 40°C and humidity curing in the moisture chamber for 7 days indicated improvement of the strength development of the mixture. The results of unconfined compressive strength (UCS) and resilient modulus testing of geopolymer-stabilized C&D aggregates indicate that alkali-activated fly ash is a viable binder for the stabilization of C&D aggregates.
TL;DR: The growing population in the modern world has resulted in an increase in waste generation and stockpiles, and there have been increasing concerns on how to sustainably reuse wastes in civil an... as discussed by the authors.
Abstract: The growing population in the modern world has resulted in an increase in waste generation and stockpiles. There have been increasing concerns on how to sustainably reuse wastes in civil an...
TL;DR: In this paper, the discharge capacity of prefabricated vertical drain (PVD) is measured in the laboratory, with and without surrounding soils, and the effects of these factors are investigated, reviewed and discussed in this paper.
TL;DR: In this article, the authors investigated the behavior of lime stabilized compacted expansive soil from weathered Quaternary Volcanic geological deposits located in Western Victoria; Australia and found that the maximum deformation occurs in the second swelling cycle.
TL;DR: In this paper, nine anthropic hazards due to the underground construction in recent years at Asian countries are discussed and each case study discussed the project description, geological conditions, the collapse and its consequence, and analysis of failure mechanism according to field investigations.
Abstract: Many hazards occurring due to underground construction works can be attributed to anthropic activities. It is important to know what new knowledge on both geology and construction operation are needed to prevent these hazards from leading to catastrophic failures. In this paper, nine anthropic hazards due to the underground construction in recent years at Asian countries are discussed. Each case study discussed the project description, geological conditions, the collapse and its consequence, and analysis of failure mechanism according to field investigations. Furthermore, to explore the cause of the collapse and to prevent similar hazards from leading to failures, the collapsed excavations of the selected case studies were studied extensively. Based on the field investigations undertaken in this study, underground construction collapse which can be attributed to human-induced activities are overexcavation, water leakage, soil deterioration, faults in design and implementations, erosion, and inadequate ground improvement. The understanding of the effect of these human-induced activities can be used as a guideline for avoiding hazards in future projects.
TL;DR: In this paper, the authors investigated the contact erosion failure at the foundation of a pavement embankment constructed with dispersive soil as a result of groundwater fluctuation, where the constriction sizes of the granular materials used for a working platform are comparatively higher to restrict the erosion of overlying embankments materials.
Abstract: Soft subgrades are not strong enough to provide the required degree of compaction for a pavement embankment’s foundation. Therefore, it is required to treat the subgrade soil or construct a working platform on top of the soft subgrade to ensure proper compaction of the subsequent layers. The constriction sizes of the granular materials used for a working platform are comparatively higher to restrict the erosion of overlying embankment materials. This condition would lead to severe material loss in the embankment layer in cases where the embankment is constructed with dispersive soil, which becomes structurally unstable in wet conditions and appears to disperse in water. This paper investigates the contact erosion failure at the foundation of a pavement embankment constructed with dispersive soil as a result of groundwater fluctuation. Experimental studies were conducted on a laboratory model test apparatus designed to simulate the conditions in the pavement embankment’s foundation. The experimenta...
TL;DR: In this article, a series of experiments were conducted to understand the hydrological and physical responses of shallow slopes subject to rainfall events, which is vital for the efficiency of a warning system setup.
Abstract: Understanding the hydrological and physical responses of shallow slopes subject to rainfall events is vital for the efficiency of a warning system setup. In this research, a series of experiments w...
TL;DR: In this paper, the physical and mechanical properties of marginal lateritic soil and Melamine Debris (MD) blends were evaluated as a sustainable engineering fill material for road construction. And the results indicated that MD as non-plastic coarse-grained and durable material (LA = 11.3%) can be used as an alternative replacement material for engineering fill materials.
TL;DR: In this article, large-scale physical model tests for seepage flow through an MSE wall were undertaken with and without an L-shaped geocomposite drain, and the effect of water retention characteristic (WRC) on the response of MSE walls was examined.
Abstract: Mechanically stabilised earth (MSE) walls are made of unsaturated soil that is strengthened with artificial materials. They have been widely used over the past three decades; however, occasional failures due to inadequate drainage during heavy rainfall have been encountered. Essentially, the reinforced zone of the MSE wall must be protected from water inflow for the system to work satisfactorily. Recent studies have reported on the alternative use of geocomposites to replace the conventional drainage system in MSE walls, typically comprising well-graded gravel. Geocomposites comprise a core material with a large flow channel, which is covered by a nonwoven geotextile. Although it is widely recognised that geotextiles possess a water retention characteristic (WRC), only a few studies have examined the effect of WRC on the seepage responses of MSE walls. In this research, large-scale physical model tests for seepage flow through an MSE wall were undertaken with and without an L-shaped geocomposite drain. Co...
TL;DR: In this article, a camera-based system inside the triaxial cell was used to measure the volume and volumetric strains of soil specimens during the test, which was shown to eliminate the optical distortions due to refraction at the fluid-cell wall and cell wall-atmosphere interfaces.
Abstract: Salazar et al. (2015) presented a new method to measure the volume and volumetric strains of soil specimen during the triaxial test. To eliminate the optical distortions due to refraction at the fluid-cell wall and cell wall-atmosphere interfaces, they installed a camera-based system inside the triaxial cell. The discussers wished to highlight some points about taking into account the refraction of light and other related issues in image processing for evaluating the volumetric strains and show that there is another simple way to overcome this problem.
TL;DR: In this paper, the effect of molding water contents (on dry and wet sides of optimum water content) on the pullout resistance mechanism of the bearing reinforcement embedded in a marginal lateritic soil is investigated.
TL;DR: In this paper, a finite element (FE) investigation on GFRP concrete composite deck using a concrete wedge shear connection system based on existing experimental evaluation is presented, and an equation is proposed to estimate the deflection at the mid-span of the G FRP composite bridge deck based on the FEM results.
TL;DR: In this article, a hydraulic consolidation cell at the moisture contents of 150 and 168% was used for step loading compression measurements of ultra-soft soil, obtained from marine environment, and three different drainage conditions were tested: radial outward, inward, and both inward and outward drainages.
Abstract: Step loading compression measurements of ultra-soft soil, obtained from marine environment, were carried out with a hydraulic consolidation cell at the moisture contents of 150 and 168%. Three different drainage conditions were tested: radial outward, inward, and both inward and outward drainages. Ultra-soft soil showed a significant settlement in the first step of loading. There was little pore pressure dissipation, which implies little effective stress gain and with large magnitude of settlement in low stress range. New compression parameters , , and are proposed for viscous and intrinsic states inclusive of low stress log cycles. A correlation between void ratio at 10 kPa effective stress () and void ratio at liquid limit eL was proposed and the relevant compression parameters were predicted. The magnitudes of settlements at various loadings were subsequently predicted using the proposed basic equations and were found to agree well with the measured data. Dimensionless time factor curves for various ra...
TL;DR: In this paper, the effect of compaction techniques on resilient behavior of compacted laboratory specimens is investigated, and it is shown that the resilient behaviour of unsaturated compacted road pavement materials is influenced by suction.
TL;DR: In this paper, the pullout resistance mechanism of the bearing reinforcement embedded in the compacted residual soils (red clay and claystone), which is required for BRE wall design, is investigated.
Abstract: A bearing reinforcement earth (BRE) wall was proposed as an alternative, temporary structure replacing a natural slope to enhance performance and slope stability. The pullout resistance mechanism of the bearing reinforcement embedded in the compacted residual soils (red clay and claystone), which is required for BRE wall design, is investigated in this paper. The pullout resistance predictive method is recommended for both soils. The pullout resistance of the bearing reinforcement comprises both friction and bearing components. The peak interface factor (αp) between the soil and the longitudinal member is found to be 0.66 and 0.40 for red clay and claystone, respectively, while the residual interface factor (αr) is 0.47 and 0.22 for red clay and claystone, respectively. Though the red clay has a higher αp and αr than the claystone, the friction pullout resistance is lower than that of the claystone due to a lower shear strength. The pullout bearing resistance of transverse members (Pbn) can be calculated ...
TL;DR: In this article, an engineering geological study was undertaken to determine the engineering properties, and mineralogy of ultrasoft soils (USS) obtained from a nearshore mine tailings sedimentation pond.
Abstract: An engineering geological study was undertaken to determine the engineering properties, and mineralogy of ultrasoft soils (USS) obtained from a nearshore mine tailings sedimentation pond. The USS is a high plasticity clay of high water content and low shear strength. Marine bathymetric and seismic reflection surveys were undertaken in the sedimentation pond located in the foreshore of the Eastern part of the Republic of Singapore. Specimens collected from the bore holes were tested to determine the engineering and mineralogy properties of the USS. Field vane shear tests were undertaken just adjacent to the sampling bore holes to determine the shear strength properties of the USS. The mineralogical properties of the USS were determined using X-ray diffraction and scanning electron microscope techniques. The USS is under consolidated soil where higher density and lower water content were found at deeper depth. The USS had three different compression indices under three log cycles of effective stress between...