Such a function does not exist. Indeed, let $f\colon[a,b]\to\mathbb R$ be an increasing differentiable function. Then $$f(x)-f(a)=(HK)\int_a^x f'(t)\,dt$$ for all $x$, where $(HK)\int$ is the [Henstock–Kurzweil integral][1]. In particular, $f'$ is Henstock–Kurzweil integrable on $[a,b]$. Therefore and because $f'\ge0$, $f'$ is Lebesgue integrable on $[a,b]$, and hence $$f(x)-f(a)=(L)\int_a^x f'(t)\,dt$$ for all $x$, where $(L)\int$ is the Lebesgue integral. So, $f$ must be absolutely continuous. [1]: https://en.wikipedia.org/wiki/Henstock%E2%80%93Kurzweil_integral#Properties