Effect of Fly Ash Fineness on the Performance of Cement Mortar

This paper investigates the effect of fineness of fly ash on the performance of cement mortar. Fly ash from thermal plant is used as partial substitute for cement. Fly ash is used as received and also processed by grinding. The study involves four replacement levels of fly ash into cement at 10%, 20%, 30% and 40% for each mix design. Mortar cubes are tested for strength, water absorption and sorption. Water absorption and sorption show a decreasing trend with the increase of fly ash fineness; whereas the strength increases with the increase of fineness. It is concluded that increasing the fineness of fly ash increases the strength and reduces absorption by 15% and hence is an effective method to improve its performance in cement mortar

State of the Art Review on Prescriptive & Performance Based Approaches for Concrete Durability

Durability is a crucial and important requirement for concrete structures.  A durable concrete not only leads to sustainability but serve for longer period of time without much repair and maintenance.  The Concrete has been studied under various exposure conditions as stated in relevant standards but no significant attention is given for the in service performance of the concrete. In the last few decades, many researchers investigated the causes of structures deterioration and suggested various solutions to tackle the durability issues which are mainly adopting of performance-based specifications rather than prescriptive. In this paper, the previous findings on concrete durability are reviewed. The studies on the durability problems are highlighted along with prescriptive and performance-based approaches and test methods.  The effects on service life of the structures along with the solution are reviewed

Axially Loaded Steel Columns Strengthened with CFRP

During the recent decades, Carbon Fiber-Reinforced Polymer (CFRP) composite materials have proven valuable properties and suitability to be used in the construction of new buildings and in upgrading the existing ones. The objective of this paper is to review the previous work in this area and compare it with the current experimental results to show the design equations for CFRP strengthened steel structural elements. Research findings have shown that CFRP sheets and strips are not only effective in restoring the lost capacity of a damaged steel section, but are also quite effective in strengthening of steel sections to resist higher loads, extend their fatigue life and reduce crack propagation

Pushover Analysis for Cold Formed Storage Rack Structures

This study investigated the progressive collapse of cold formed storage rack structures subjected to seismic loading, using pushover analysis. A simple storage rack cold formed steel structure was analyzed with static, non-linear procedure in accordance with FEMA 356 specifications and progressive collapse recorded such as occupancy, immediate occupancy, life safety and collapse prevention. Pushover analysis was found to be a useful analysis tool for the conventional storage racking systems giving good estimates of the overall displacement demands, base shears and plastic hinge formation

Numerical Studies on CFRP Strengthened Cold formed Steel built-up Columns

This paper reports the numerical investigation carried out on the Cold-formed steel (CFS) built up columns strengthened with a Carbon fiber-reinforced polymer (CFRP) by using Finite element software ABAQUS/CAE. The CFS sections used in the investigation are built-up Cold formed box sections connected together by screws. Totally 24 columns are considered for the analysis in that twelve columns used are plain CFS and other 12 columns used are CFRP strengthened CFS columns. The geometric properties of the materials considered as 0.6 mm, 0.75 mm and 1 mm thickness with 300 mm, 500 mm and 700 mm depth respectively. All the built-up columns were modeled and analysed using ABAQUS software. From the analysis results, the Ultimate load capacity, Buckling behavior and Load-lateral displacement of the Plain and CFRP strengthened columns are obtained and presented in this paper. It is also noted that the numerical results obtained from the ABAQUS software is in good agreement with the experimental results

INFLUENCE OF CURING ON THE PROPERTIES OF HIGH VOLUME FLY ASH CONCRETE

Fly ash concrete is the most widely used material in building construction. This is because adding fly ash in concrete reduces the cement consumption and contributes less emission. Normal constituents in concrete are cement and aggregates. Adding fly ash in concrete will enhance the performance of normal concrete. The high volume fly ash concrete is prepared at a ration of 1: 1.5: 3 cement: fine aggregate: coarse aggregate. The concrete is then kept in three different curing regimes. The concrete was then tested for its compressive strength, water absorption and initial surface absorption (ISAT). It is concluded that concrete cured under the normal water curing condition gives the best performance results

Mechanical properties and durability of calcium carbide kiln dust mortar

This paper reports an investigational study on the effect of calcium carbide kiln dust (CCKD) in cement mortar and its resistance towards hydrochloric acid attack. Mortar with various CCKD replacement levels from 5 to 40 percent by binder weight were tested. The setting time, consistency, density, compressive strength and the durability tests were evaluated to measure the effect of CCKD in mortar. The durability was assessed in terms of loss of density and strength when the specimen were cured in 5% hydrochloric acid (HCL) solution. The results indicate that CCKD replacement levels from 5 to 20 percent performed on par with control mix in terms of compressive strength, the loss in density and strength were around 30% under acid curing. However, 30% and above CCKD replacement percentage showed low density and compressive strength in both conditions. It is concluded that CCKD can be used as an effective replacement for cement up to 20 percent without affecting the performance. © IAEME Publication