Embodied energy of RHA

Dan — Tue, 26 Jun 2018 11:09:09 +0000

Hi Geoffrey,

thanks for all your previous help and information,
wandering if you have any embodied energy calculations for RHA MJ/kg?

Much appreciated as always!

Dan

Dan Tue, 26/06/2018 - 18:09

Embodied Energy of RHA

Not yet. A few years ago we did have a crack group of 4 University of Melbourne students work on RHA comminution (the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes). They did come up with a number that describes the relative difficulty or energy needed to break down the material. And, they came up with a concept for a new way of grinding RHA. If the ash is from another process (e.g., fuel firing for an electric power plant) then the embodied energy of RHA comes only from handling and comminution.

Thanks!

RHA, Rice Husk Ash Cement

Lime-RHA Binder

T_Nhien — Mon, 11 Jun 2018 09:01:26 +0000

Lime-RHA Binder

Dear Geoffrey,
I am currently experimenting with hydrated lime and raw rice husks to build insulating panels. As a binder I would like to use a mix of lime, pozzolan and a small amount of cement to increase the initial setting and at the same time maintaining the advantage of lime (carbonation effect).

I have a few questions and I hope you can give me some advice on Lime-RHA based binder:
1) According to your experience what would be the most suitable binder mix, i.e. Lime/RHA/OPC and binder/water ratio?
2) can you please provide me your RHA specs as well.

Thank you. I am looking forward to hearing from you.

Best regards,
Nhien

T_Nhien Mon, 11/06/2018 - 16:01

Appropriate RHA substitution and RHA properties.

1. We can successfully replace at least 30% of lime or OPC [ordinary portland cement) with RHA (finely ground rice husk ash). The RHA pozzolan tends to drink up more water so it is necessary to use a superplasticizer in order to keep the W/C ratio (water to cement ratio) below .40 In Thailand there are already lime/opc cements available so it is probably not necessary to mix your own although you can.

2. The RHA spec's or properties can mean the percent constituents of various elements and minerals. To determine these some high-tech laboratory analysis is required. This is suitable for scientific research endeavors. If we are working on finding and appropriate mix, especially in a precast concrete product situation, then we cast several trial mixes, cure the products for appropriate lengths of time (3, 7, 28 days) and then test the product strength against an appropriate standard (TIS, ASTM, BS, etc.) and against 100% opc mixes.

Appropriate RHA substitution and RHA properties.

Thank you for your reply. Can you please advice which manufacture/brand in Thailand supplies Lime/OPC cements and do you know the lime/opc ratio?
Thank you.

"Mixed" Cement

I believe that all cement companies in Thailand offer a "mixed" cement such as Siam City Cement Company's Insee Daeng.

I have an inquiry in to see if we can get a lime/OPC ratio for it. Again, it is fairly straight forward to make some sample blocks with various lime/cement ratios and do some compression tests on them. "The proof is in the pudding," as the Yankees say. It is not essential to know the lime/OPC ratio of the cement.

RHA, Rice Husk Ash Cement