Combined Recycling of White Rice Husk Ash as Cement Replacement and Metal Furnace Slag as Coarse-Aggregate Replacement to Produce Self-Consolidating Concrete

According to empirical evidence,high levels of energy and considerable amounts of natural resources are used in the production of concrete.Given the context,this study explores self-consolidating concrete(SCC)that includes rice husk ash(RHA)and metal furnace slag(MFS)as an alternative to cement and the natural aggregates in standard SCC mixes.In this study,mixture designs are investigated with 20 wt.%of RHA,10–30 wt.%of MFS and water-to-powder material ratios of 0.30 and 0.40.Based on the findings regarding the fresh-state,hardened-state,and durability properties of the resulting SCC mixes,it is evident that the use of RHA and MFS can significantly improve the properties of concrete.The highest compressive strength was achieved for SCC with 20 wt.%RHA and 10 wt.%MFS.This outcome should be used as a basis for further investigations into the production of concrete materials that are both high-performance and sustainable.

Potentials of Balanite Endocarp Pod Ash as a Cement Replacement Material

The exponential growth of agricultural wastes such as Balanite seed pod has resulted in waste management issues and finding alternatives through waste recycling is an interesting area of research.Balanite seed pods were collected in Yobe state,washed,dried,crushed.Balanite endocarp pod ash(BEPA)was calcined at 600°C for 3 hours in a muffle furnace and the biomass was characterized with X-ray fluorescence spectrometer to determine its chemical composition.The analysis showed that the ash composed of silica,alumina and ferric oxide(74.24 wt.%)indicated a strong pozzolan based on American Standard.The BEPA possessed a high loss on ignition of 8.24 wt.%owing to the presence of unburnt carbon in the ash.The ash obtained was sieved with 75µm sieve and cement was replaced with ash between 2.5 wt.%~12.5 wt.%at interval of 2.5 wt.%to assess its impact on cement properties such as setting time,consistence,mortar strength and water absorption.Results showed that as percentage replacement increases,the water absorption increased while the mortar strength diminished whereas as the curing days progressed its strength improved despite clinker diminution due to cement hydration.60 days strength for below 10 wt.%BEPA cement blend produced enhanced strength compared with control which is evidence of slow pozzolanic reactions.The optimum percentage replacement with BEPA was obtained at 7.5 wt.%replacement beyond which significantly affected the cement properties especially its strength.It could be agreed that BEPA has potentials to be considered and employed as a cement replacement material.

The finite element analysis of cemented long and short stem prosthetic replacement in aged patients with comminuted intertrochanteric fracture

Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long

Effect of fineness of ash on pozzolanic properties and acid resistance of sugarcane bagasse ash replaced cement mortars

This paper addresses the potential use of Sugar Cane Bagasse Ash(SCBA)as a pozzolanic material for partial cement replacement in concrete mixtures.Cement mortars containing SCBA having five different particle size distributions at a replacement rate of 20%by weight were used to study the chemical and physical pozzolanic properties of SCBA.The durability of SCBA replaced mortars was also evaluated.SCBA with 0%retained on sieve No.325 was used to replace 20%by weight of cement and create mortar specimens that were subjected to sulfuric acid attack of varying concentrations(1%–3%by weight of water).The tested samples were observed to check visual distortion,mass loss,and compressive strength loss at 1,7,14,28,and 56 d of acidic exposure,and the results were compared to those for the control sample,that was lime water cured,at the same ages.The SCBA sets were found to meet the requirements for pozzolan class N specified by ASTM C 618.Mortars containing SCBA with 0%or 15%retention produced better compressive strength than the control mortars after 28 d.Additionally,X-ray fluorescence and X-ray diffraction analysis showed that the SCBA had favorable chemical properties for a pozzolanic material.Furthermore,SCBA replaced samples at all ages showed improved resistance against acidic attack relative to that of the control mortars.Maximum deterioration was seen for 3%concentrated solution.This study’s findings demonstrated that SCBA with an appropriate fineness could be used as a pozzolanic material,consistently with ASTM C 618.

Effects of seeding nucleation agent on geopolymerization process of fly-ash geopolymer

Geopolymer, an inorganic aluminosilicate material activated by alkaline medium solution, can perform as an inorganic adhesive. The geopolymer technology has a viability to substitute traditional concrete made of portland cement （PC） because replacing PC with fly ash leads to reduced carbon dioxide emissions from cement productions and reduced materials cost. Although fly ash geopolymer stimulates sustainability, it is slow geopolymerization reaction poses a challenge for construction technology in term of practicality. The development of increasing geopolymerization reaction rate of the geopolymer is needed. The purpose of this study is to evaluate seeding nucleation agents （NA） of fly ash geopolymer that can accelerate polymerization reactions such that the geopolymer can be widely used in the construction industry. Results from the present study indicate that the use of NA （i.e., Ca（OH）2） can be potentially used to increase geopolymerization reaction rate and improve performance characteristics of the fly ash geopolymer product.