Thermal Properties and Drying Shrinkage Performance of Palm Kernel Shell Ash and Rice Husk Ash-Based Geopolymer Concrete

Abstract

This study aims to develop suitable formulations of geopolymer concrete (GPC) by varying the percentages of the geopolymer with aggregates and evaluating the performances in thermal and mechanical properties of palm kernel shell ash (PKSA)-GPC compared to rice husk ash (RHA)-GPC and ordinary Portland cement concrete (OPCC). Preliminary tests were conducted to select the best mix design ratios before casting the specimens. Then, the performance of the PKSA-GPC, RHA-GPC and OPCC specimens was evaluated based on their thermal performance and drying shrinkage. The mix designs of PKSA-GPC 70:30, PKSA-GPC 60:40, PKSA-GPC 50:50 and PKSA-GPC 66.6:33.3 were found to produce an acceptable consistency, rheological and thixotropic behaviour for the development of the GPC. PKSA-GPC showed a better thermal performance than the RHA-GPC and OPCC due to their strong and dense intumescent layers and slow temperature increment upon exposure to a high flame temperature from ambient temperature to 169 °C. The low molar ratio of the Si/Al present in the PKSA-GPC created a thermally stable intumescent layer. In the drying shrinkage test, PKSA-GPC 60:40 and RHA-GPC 60:40 shared an equal drying shrinkage performance (5.040%) compared to the OPCC (8.996%). It was observed that microcrack formation could significantly contribute to the high shrinkage in the PKSA-GPC 50:50 and RHA-GPC 70:30 specimens. The findings of this study show that PKSA could be incorporated into GPC as a fire-retardant material due to its capability of prolonging the spread of fire upon ignition and acting as an alternative to the conventional OPCC.

Investigation of the Effect of Blended Aggregate on the Strength and Drying Shrinkage Characteristics of Alkali-Activated Slag Mortar

“…It has been reported that AASC can reduce CO 2 emissions by 25-80% relative to OPC [11][12][13]. AASC has similar or better mechanical performance and durability than OPC [14][15][16][17]. However, in order to apply AASC to full-scale construction, certain problems, such as low carbonation resistance [18][19][20], alkali-aggregate reaction [21], and shrinkage [22][23][24][25][26][27][28][29][30], must be solved or improved.…”

Effect of a Hybrid Pumice–Portland Cement Extract on Corrosion Activity of Stainless Steel SS304 and Carbon Mild Steel A36

“…These cements involve the partial or complete replacement of the PC [5,6] with supplementary cementitious materials (SCM), such as natural pozzolan (volcanic materials), limestone, blast furnace slag, fly ash, calcinated clays and waste glass [7,8]. These alternative cements offer advantages including lower CO 2 emission compared to PC, good mechanical strength, thermal resistance, among others [9][10][11][12].…”