Study the retardant effect of using different sugar's types on setting time and temperature of cement paste

This paper present the study of the effect of adding different sugar types such as (Granular, Caster, Brown and Beet) on setting time and temperatures of hydration of cement paste. The effect of sugar on the setting times was checked by testing numbers of cement paste samples, that produce from 35% w/c ratio and different sugar type and ratio (0.5%, 1.5%, 2.5% and 5%) by the cement weight using Vi-cat needle apparatus. While the temperatures of hydration heat were measured by using Thermocouples, and changes in the heat of hydration were clearly recognised. The results of the experimental works show that: adding any type of cane sugar (Granulated, Caster and Brown sugar) in proportion (0.5% and 1.5%) the sugar was works as a concrete retardant, but these type of sugar worked as concrete accelerator when used in proportion (2.5% and 5%). However; adding Beet sugar in proportion (0.5%, 1.5%, 2.5% and 5%) was working as a concrete retardant. On the other hand, the hydration temperatures increased by adding sugar and the high peak they reached was about 33.890C at 0.30 water ratio with 1.5% sugar content. It obvious, for all sugar type (1.5% by cement weight) was the optimum sugar proportion to retard the final setting time of the cement pastes of different w/c ratios, but the higher sugar contents cause a decrease in the final setting time. On other hand, the initial setting time was decreased and accelerated when sugar was added to the paste. As well as adding sugar to the cement paste improved it physically by reduced the cracking and the bleeding on the surface of the sample. © IAEME Publication

Soft Soil Stabilisation Using High Calcium Waste Material Ash

Civil engineering projects located in areas with soft soil present some of the most common problems in many parts of the world. Depending on the nature of the project, expensive solutions are sometimes used, which commonly involves the removal and replacement of the weak soils. Alternatively, ground improvement is now considered the best solution for such problems. Soil improvement can be achieved either by mechanical and/or chemical stabilisation. To reduce the use of cement and lime as the most traditional stabilizers applied to soft soils, sustainable waste materials have been increasingly used for soil stabilisation. This paper presents the results of a laboratory study on the stabilisation of silty clayey soil using a waste material fly ash (FA) with high calcium content produced from the incineration processes in domestic power stations. The FA used in this study has a high content of calcium oxide CaO and suitable content of silicon dioxide SiO2 (more than 25%). These cementitious and pozzolanic properties are responsible for the self-cementing characteristics of this fly ash. An intermediate plasticity silty clayey soil with medium organic matter content has been used in this study. The effect of FA on the physical and engineering properties on the selected soil such as the consistency limits, compaction characteristics (optimum moisture content and maximum dry density), and soil strength (unconfined compressive strength (UCS)), has been investigated. Different percentages of fly ash were added to the soft soil (1.5, 3, 6, 9, 12, and 15%) to produce different admixtures. Improvement levels were evaluated dependant on the UCS tests carried out on specimens at different periods of curing (zero, 7, 14, and 28 days). Results indicated that the maximum dry density decreased and the optimum moisture content increased with the increase of the FA content. In terms of the UCS tests, the results yielded the optimum value of the FA used in this study to be 12.0%, as this percentage decreased the index of plasticity (IP) significantly. The results of this study indicated that the use of this waste material could produce a significant cementitious reaction when added to the soil, and it could be used as a supplementary cementitious material

A laboratory study of high-performance cold mix asphalt mixtures reinforced with natural and synthetic fibres

This research aims to examine the impact of using natural and synthetic fibres as reinforcing materials, on the mechanical properties and water susceptibility of cold mix asphalt (CMA) including indirect tensile stiffness and resistance to rutting, cracking and moisture damage. Four different types of fibres were used: glass as a synthetic fibre, and hemp, jute and coir as natural fibres. Various samples of CMA, with and without fibres, were fabricated and tested. Traditional hot mix asphalt (HMA) was also used for comparison. The results indi cate a significant improvement in the indirect tensile stiffness modulus, for all fibre-reinforced CMA mixtures, over different curing times. The improved tensile behaviour represents a substantial contribution towards slowing crack propagation in bituminous mixtures, while scanning electron microscopy analysis confirmed the fibre shape and surface roughness characteristics. The improved performance of the reinforced mixtures with both natural and synthetic fibres, facilitated a substantially lower permanent deformation than traditional hot and cold mixtures at two different temperatures (45 °C and 60 °C). When using glass and hemp fibres as reinforcing materials, there was a significant improvement in CMA in terms of water sensitivity. Resistance to surface cracking was also improved when fibres were incorporated. Based on the test results, 0.35% fibre content by mass of dry aggregate and 14 mm fibre length are recommended to achieve the optimum performance output for indirect tensile stiffness. © 2018 Elsevier Lt

Predicting the rutting behaviour of natural fibre-reinforced cold mix asphalt using the finite element method

This paper describes the development of a three-dimensional (3-D), finite element model (FEM) of flexible pavements made with cold mix asphalt (CMA), which has itself been reinforced with two different natural fibres: jute and coir. A 3-D finite element model was employed to predict the viscoelastic response of flexible CMA pavements when subjected to multiple axle loads, different bituminous material properties, tire speeds and temperatures. The analysis was conducted by the finite element computer package ABAQUS/STANDARD. The pavements were subject to cyclic and static loading conditions to test for permanent deformation (rutting). The accuracy of the developed model was validated by comparing the predicted results with those measured in the lab. Reinforced and unreinforced CMA mixture models were simulated in this research. The results indicate that the CMA mixtures reinforced with natural fibres, are effective in mitigating permanent deformation (rutting). These reinforcing materials can extend the service life of flexible pavements. © 2018 Elsevier Lt

The Utilisation of Two Types of Fly Ashes Used as Cement Replacement in Soft Soil Stabilisation

This study represents the results of an experimental work using two types of fly ashes as a cement replacement in soft soil stabilisation. The fly ashes (FA1 and FA2) used in this study are by-products resulting from an incineration processes between 800 and 1200 ˚C. The stabilised soil in this study was an intermediate plasticity silty clayey soil with medium organic matter content. The experimental works were initially conducted on soil treated with different percentages of FA1 (0, 3, 6, 9, 12, and 15%) to identify the optimum FA1 content. Then FA1 was chemically activated by FA2 which has high alkalinity by blending the optimum content of FA1 with different portions of FA2. The improvement levels were evaluated dependent on the results obtained from consistency limits and compaction tests along with the results of unconfined compressive strength (UCS) tests which were conducted on specimens of soil treated with FA1 and FA2 and exposed to different periods of curing (zero, 7, 14, and 28 days). The results indicated that the FA1 and FA2 used in this study effectively improved the physical and geotechnical properties of the soft soil where the index of plasticity (IP) was decreased significantly from 21 to 13.17 with 12% of FA1; however, there was a slight increase in IP with the use of FA2. Meanwhile, 12% of FA1 was identified as the optimum percentage improving the UCS of stabilised soil significantly. Furthermore, FA2 was found effective as a chemical activator to FA1 where the UCS was improved significantly after using FA2

Mechanical Activation of a Waste Material Used AS Cement Replacement in Soft Soil Stabilisation

Waste materials, sometimes called by-product materials have been increasingly used as replacement materials to reduce the usage of cement in different construction projects. In the field of soil stabilisation, waste materials such as pulverised fuel ash (PFA), biomass fly ash (BFA), sewage sludge ash (SSA), etc.; have been used since the 1960s. In this study, a particular type of a waste material (WM) was used in soft soil stabilisation as a cement replacement combined with the effect of mechanical activation, using grinding, to enhance the performance. The stabilised soil in this study was an intermediate plasticity silty clayey soil with medium organic matter content. The experimental investigations were conducted to find the optimum content of WM by determining the Atterberg limits and the unconfined compressive strength (UCS) of soil samples containing (0, 3, 6, 9, 12, and 15%) of WM by the dry weight of soil. The UCS test was carried out on specimens exposed to different curing periods (zero, 7, 14, and 28 days). Moreover, the optimum percentage of the WM was subject to different periods of grinding (10, 20, 30, 40mins) using a mortar and pestle grinder to determine the effect of grinding and its optimum time by conducting UCS tests. The results indicated that the WM used in this study improved the physical properties of the soft soil where the index of plasticity (IP) was decreased significantly from 21 to 13.10 with 15% of WM. Meanwhile, the results of UCS test indicated that 12% of WM was the optimum and this percentage developed the UCS value from 202kPa to 700kPa for 28 days of curing. In terms of the time of grinding, the results revealed that 10 minutes of grinding was the best for mechanical activation for the WM used in this study

Assessing the Potential of a Waste Material for Cement Replacement and the Effect of Its Finennes in Soft Soil Stabilisation

This paper represents the results of experimental work to investigate the suitability of a waste material (WM) for soft soil stabilisation. In addition, the effect of particle size distribution (PSD) of the waste material on its performance as a soil stabiliser was investigated. The WM used in this study is produced from the incineration processes in domestic energy power plant and it is available in two different grades of fineness (coarse waste material (CWM) and fine waste material (FWM)). An intermediate plasticity silty clayey soil with medium organic matter content has been used in this study. The suitability of the CWM and FWM to improve the physical and engineering properties of the selected soil was evaluated dependant on the results obtained from the consistency limits, compaction characteristics (optimum moisture content (OMC) and maximum dry density (MDD)); along with the unconfined compressive strength test (UCS). Different percentages of CWM were added to the soft soil (3, 6, 9, 12 and 15%) to produce various admixtures. Then the UCS test was carried out on specimens under different curing periods (zero, 7, 14, and 28 days) to find the optimum percentage of CWM. The optimum and other two percentages (either side of the optimum content) were used for FWM to evaluate the effect of the fineness of the WM on UCS of the stabilised soil. Results indicated that both types of the WM used in this study improved the physical properties of the soft soil where the index of plasticity (IP) was decreased significantly. IP was decreased from 21 to 13.64 and 13.10 with 12% of CWM and 15% of FWM respectively. The results of the unconfined compressive strength test indicated that 12% of CWM was the optimum and this percentage developed the UCS value from 202kPa to 500kPa for 28 days cured samples, which is equal, approximately 2.5 times the UCS value for untreated soil. Moreover, this percentage provided 1.4 times the value of UCS for stabilized soil-CWA by using FWM which recorded just under 700kPa after 28 days curing

Performance analysis of a Cold Asphalt Concrete Binder Course Containing High Calcium Fly Ash Utilizing Waste Material

It has been established that cold bituminous emulsion mixtures (CBEMs) have a comparatively low initial strength in comparison to hot mix asphalt (HMA), however its superior performance with regard to carbon emissions, is a significant driver regarding its manufacture. In this research, high calcium fly ash (HCFA) together with a fluid catalytic cracking catalyst (FCC) - a rich silica-alumina waste material - have been incorporated to develop a new cold asphalt concrete binder course (CACB) bituminous emulsion mixture. HCFA was used as a substitute for traditional limestone filler while FCC was the additive used to activate the HCFA. The mixtures’ performance was assessed using the indirect tensile stiffness modulus test (ITSM), assessment of resistance against permanent deformation, temperature and water sensitivity tests. Surface morphology was tested using a scanning electron microscopy (SEM). A considerable improvement was identified by the ITSM test in addition to a substantial enhancement in rutting resistance, temperature susceptibility and water sensitivity. It was also established that the addition of FCC to CACB mixtures was found to improve early strength as well as long-term strength, rutting resistance, temperature sensitivity and durability

Improving the geometry of manholes designed for separate sewer systems

The design of manholes dates back more than 100 years. However, there have been developments such as the use of new materials for the manufacture of manholes, and advances in inspection and maintenance technologies, allowing improvements to the shape of manholes. This paper presents an innovative design for manholes, created to overcome the challenges associated with the installation of separate sewer systems in narrow streets, common to both UK and EU cities. The traditional separate sewer system has two separate manholes. The proposed manhole combines these two manholes into one structure, with two separate chambers, to allow storm flow and foul flow to pass through the same manhole without mixing. The structural performance of the new design has been tested using mathematical modelling validated by experimental tests. The results are compared with the structural performance of traditional manholes. The new design shows an improved resistance to high live loads

Laboratory Studies to Examine the Properties of a Novel Cold-Asphalt Concrete Binder Course Mixture Containing Binary Blended Cementitious Filler (BBCF)

Conventional hot asphalt mixtures have an impact on global warming and CO2 emissions contributing to debates on environmental issues which have been raised in recent years. As an alternative, cold emulsion asphalt mixtures (CBEMs) provide considerable benefits such as eco-friendliness, energy efficiency and cost effectiveness connected with safety. However, their weak early strength along with the need for longer curing times (usually 2-24 months) and higher moisture susceptibility compared to hot asphalt mixtures, have been cited as obstacles to their wider application. That said, the incorporation of waste materials in CBEM mixtures enhances sustainability by decreasing the amount of industrial waste materials needed and conserving natural resources. A new binary blended cement filler (BBCF) material generated from high calcium fly ash (HCFA) and fluid catalytic cracking catalyst (FC3R) was found to be very effective in providing microstructural integrity with a novel fast-curing cold asphalt concrete for the binder course (CACB) mixture. Laboratory performance tests included the stiffness modulus test by indirect tension to cylindrical samples, wheel-tracking tests and water sensitivity. Regarding environmental issues, a toxicity characteristic leaching procedure (TCLP) test was performed to analyse the leachate from various specimens comprising concentrations of heavy metal. The findings of these tests have demonstrated that CACB performs extremely well compared to traditional hot mixtures. The stiffness modulus of the BBCF treated mixture – 3730 MPa after 3 days – is higher than the traditional hot mixture (100/150 pen). In addition, the BBCF treated mixture offered a superior performance regarding rutting resistance, fatigue resistance and water susceptibility as well as revealing a considerably lower thermal sensitivity. More significantly, the BBCF treated mixture was found comparable to the traditional asphalt concrete binder course after a very short curing time (1 day). Finally, the concentration of heavy metals in the specimens incorporating the BBCF was observed to be less than the regulatory levels determined for hazardous materials and so requirements were satisfied. Consequently, this BBCF treated mixture has significant potential with reference to its application as a binder course in asphalt pavement