ANALYSIS ON THE INTEGRITY, SURFACE HARDNESS AND POROSITY OF AUTOCLAVED LIGHTWEIGHT CONCRETE

• Main Author: Hassan, Mohammad Hailz
• Format: Final Year Project
• Language: English
• Published: Universiti Teknologi Petronas 2004
• Subjects: TA Engineering (General). Civil engineering (General)
• Online Access: http://utpedia.utp.edu.my/6774/1/2004%20-%20ANALYSIS%20ON%20THE%20INTEGRITY%2C%20SURFACE%20HARDNESS%20AND%20POROSITY%20OF%20AUTOCLAVED%20LIGHTWEIGHT%20CONCRET.pdf; http://utpedia.utp.edu.my/6774/

Autoclaved lightweight concrete is manufactured from sand, lime and cementto which is added a gas-forming agent. Sand is grounded to a required fineness in a ball mill and stored while cement and lime are stored in silos. Water and aluminium powder (gasforming agent) are then added to the mixture. After mixing, the cement slurry is poured Into amouid for few hours before being transported to cutting machine. The final curing >f the product takesup to 12hoursunderhighsteampressurein an autoclave. n this, project^ the surface hardness, integrity and also total porosity of autoclaved ightweight concrete are being analyzed using rebound hammer, Ultrasonic Pulse Velocity (UPV) test and porosity test respectively. There are ranges of autoclaved ightweight concrete blocb varying in thickness of 25mm increment from 50mm to £50mm. However,, only blocks coded 62100 are chosen for this project which represents ettgth of^SGOmm, thickness of 2G0mm and heightof 100mm. The results are compared vith conventional 150mmconcrete samples of 1:2:4 mix that are water and air cured. All •ampies are evaluated at 7,28 and 56 days. \utoelaved lightweight concrete is much inferior compared to water-cured and air-cured conventional concrete in all the three tests performed. For UPV, the average pulse velocity recorded for autoclaved lightweight concrete is approximately half of the value )btained for normal weight concrete. In terms of surface hardness, the values are much >etter withup to 70%of that exhibited by conventional concrete. Therefore, although the otal porosities are twice more higher than normal weight concrete, these figures are jroved to be less significant to the surface hardness of lightweight concrete but yet iffecting much of its integrity.