I live in America in Chicago but I'm go to public schools. There's no place to pray Zuhr. Do I can pray both Zuhr and Asr together?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

As a basic rule, every prayer must be offered in its fixed time as mentioned in the Qur'an: {…, perform As-Salât (Iqâmatas Salât). Verily, the prayer is enjoined on the believers at fixed hours.} [4: 103]. And as proved through the sayings and practice of the Prophet (Sallallahu Alaihi wa Sallam). The Prophet (Sallallahu Alaihi wa Sallam) said: "You should offer the prayers just as you have seen me performing them" . [Reported by Imam al-Bukhari ].
But, if there are any emergencies or uncomfortable situations one may find the religion easy as Allah Says (interpretation of meaning): {…, and has not laid upon you in religion any hardship, …} [22: 78].
The Prophet (Sallallahu Alaihi wa Sallam) used to combine between the prayers of al-Zuhr and al-'Asr or between al-Maghrib or 'Isha during the time of either one of them at Arafah, Muzdalifa, while traveling or during rain. This is the opinion of the majority of Muslim scholars among them are al-Malikiyah, al-Shafi'eyah and also reported from Imam Ahmad in a narration. They restricted the combining of two prayers to the above-mentioned situations. But, al-Ahnaf believe that combining between two prayers is allowed only during Hajj at Arafah and Muzdalifa.
However, the Sunnah proves combining between two prayers during all the above mentions situations.
Some scholars even believe that the resident can combine the prayers due to some pressing need. This is supported by the Hadith of Ibn Abbas , that has been recorded by Imam Muslim , who states: "The Messenger of Allah combined the al-Zuhr and al-'Asr, and then the al-Maghrib and al-'Isha in Medinah without there being any danger or rain . Ibn Abbas was asked: 'what did he desire by that action?' He replied: 'He did not want any hardship for his Ummah'.
Moreover, Hanabilah are of the opinion that combining two prayers due to some illness or other excuses is permissible. They allow combining two prayers for a frightened person, breast-feeding woman if she faces hardship to clean herself from the frequent impurity of her infant, the woman who suffers from prolonged flow of blood or the one who suffers incontinence of urine or the one who fears for his life, property, and family.
In the light of the above details, it is safest for the questioner to act according to the opinion of the majority of Muslim scholars. So, he should perform every prayer on its fixed time.
However, if there is pressing need or emergencies he may act according to the opinion of Ibn Abbas and Hanabilah.
Allah knows best.