I don't know what is the average workload but I can tell mine. My job is not "pure quant". I work on the buy side with a small team trading equity volatility.
I start between 7.30- 8.00. I finish between 5.30 and 10.00 depending on my class schedule at Baruch. My colleagues usually leave around 8.00.
50% of my time I spend on developping of trading and backtesting tools
30% of my time I spend on using those tools for backtesting potential strategies we can enter, analyzing current market conditions, calculating the pnl and risk statistics
25% of my time I spend on commucation with brokers, managers, middle office, market strategists and browsing Quantnet of coarse
Every quant job is different.