Effects of Wood Ash on Properties of Concrete and Flowable Fill

Zhifu Yang,Jon Huddleston,Heather Brown

doi:10.4236/msce.2016.47013

Zhifu Yang, Jon Huddleston + Show 1 more

Open Access

https://doi.org/10.4236/msce.2016.47013

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Abstract

This research investigated the use of wood ash to partially replace cement or sand in conventional concrete, roller compacted concrete (RCC), and flowable fill. The main focus was to determine how the wood ash addition affected the main fresh and hardened properties of these materials. It was found that the wood ash could be successfully incorporated into the conventional concrete. In particular, the wood ash addition not only accelerated the setting, but also improved the early and the 28-day compressive strength of concrete that contained the blast furnace slag. It was also observed that the wood ash could be positively added into RCC to facilitate the compaction and reduce the risk of segregation. In addition, the wood ash can be beneficially introduced into the flowable fill mixtures to facilitate flow, to alleviate bleeding and subsidence, as well as to achieve controlled strength especially when combined with the class C or the class F fly ash.

Highlights

The widespread use of biomass fuel in the Oak Ridge National Laboratory Biomass Plant has produced approximately 100 tons of wood ash every day
The wood ash can be successfully used in conventional slag concrete, roller compacted concrete, and flowable fill
The use of wood ash in conventional concrete generally decelerated the setting of concrete

Summary

Introduction

The widespread use of biomass fuel in the Oak Ridge National Laboratory Biomass Plant has produced approximately 100 tons of wood ash every day. It was found that the use of wood ash to partially replace cement in concrete substantially increased the water demand, the setting time, and the required dosage of air-entraining admixtures as well as compromised the long-term strength of concrete. It had small impacts on the early age compressive strength, chloride penetration, and freeze and thaw durability. Roller Compacted Concrete (RCC) The materials used in RCC mainly included type I Portland cement, crushed limestone, river sand and wood ash. Three specimens were tested for each mixture and the unconfined compressive strength of each mixture was calculated by dividing the average peak load of three specimens by the cross sectional area of the cylinder

Effects of Wood Ash on Properties of Conventional Concrete

Effects of Wood ash on Properties of RCC

Effects of Wood Ash on Properties of Flowable Fill

Summary and Conclusions