All matters of infrastructure actually do come under masarif of Zakat:

“…The heads in which zakah is to be spent were never unclear. It was always spent on the poor and the needy and on the collective requirements of the Muslims. However, when the Hypocrites in the time of the Prophet (sws) raised certain doubts about these heads, the Qur’an unequivocally stated them:

إِنَّمَا الصَّدَقَاتُ لِلْفُقَرَاءِ وَالْمَسَاكِينِ وَالْعَامِلِينَ عَلَيْهَا وَالْمُؤَلَّفَةِ قُلُوبُهُمْ وَفِي الرِّقَابِ وَالْغَارِمِينَ وَفِي سَبِيلِ اللَّهِ وَاِبْنِ السَّبِيلِ فَرِيضَةً مِنْ اللَّهِ وَاللَّهُ عَلِيمٌ حَكِيمٌ (60:9)

Zakah is only for the poor and the needy, and for those who are amils over it, and for those whose hearts are to be reconciled [to the truth], and for the emancipation of the slaves and for those who have been inflicted with losses and for the way of Allah and for the welfare of the wayfarers. This is an obligation decreed by God and God is All-Knowing and Wise. (9:60)

Here are some details of the heads of zakah mentioned in this verse:

(a) الْفُقَرَاءِ وَالْمَسَاكِينِ (al-fuqara’ wa al-masakin):the poor and the needy.

(b) الْعَامِلِينَ عَلَيْهَا (al-‘amilina ‘alayha): [1] the salaries of all employees of the state.

(c) الْمُؤَلَّفَةِ قُلُوبُهُمْ (al-mu’allafat-i qulubuhum): all political expenditures in the interest of Islam and the Muslims.

(d) فِي الرِّقَابِ (fi al-riqab): for liberation from slavery of all kinds.

(e) اَلْغَارِمِينَ (al-gharimin): for helping people who are suffering economic losses, or are burdened with a fine or a loan.

(f) فِي سَبِيلِ اللَّهِ (fi sabilillah):for serving Islam and for the welfare of the citizens.

(g) اِبْنِ السَّبِيلِِِ (ibn al-sabil): for helping travellers and for the construction of roads, bridges and rest houses for these travellers…”

(Excerpt from Meezan: Javed Ahmed Ghamidi)

(Translated by Dr. Shehzad Saleem)

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[1]. A little deliberation on the expression shows state employees in reality are العَامِليْنَ عَلَى اَخْذِ الضَّرَائِبِ وَرَدِّهَا اِلىَ المَصَارِفِ (those who collect zakah and disburse it in its heads). Consequently, this is a very subtle expression which the Qur’an has adopted here to convey its purport. No doubt, generally people have not been able to comprehend this expression; however the construction I have referred to above unfolds this meaning upon very little deliberation.

Following videos explain in detail the sources of revenue for an Islamic Government, including Zakat, Property tax (khiraaj) and service charges (to understand the basis for conclusion in detail, please refer to this thread – Discussion 32830):

Please refer to the video below from 22:36 to 28:10

Please refer to the link below from 46:30 to 47:48

ilm-o-Hikmat 02-12-2018