Every municipality is hereby empowered and authorized to issue its bonds for any improvements under the provisions of this article in anticipation of special assessments to be made upon the property abutting upon the streets, alleys, public ways or easements, or sewer rights-of-way or easements, so improved, and such bonds may be in such an amount as will be sufficient to pay the entire estimated cost and expense of such improvements for which such special assessments are levied. Such municipality is also authorized to sell such bonds, but the price for which they are sold shall not be below the par value of such bonds. Such bonds shall be payable in not to exceed ten years from the date of the issuance thereof, and shall bear interest at not to exceed twelve percent per annum, payable at such times, as shall be determined by the governing body of the municipality; and in the issuance and sale of such bonds, the municipality shall be governed by all the restrictions and limitations of the Constitution of this state, and by the restrictions and limitations of the statutes of this state with respect to the issuance and sale of other bonds, so far as they are not in conflict with the provisions of this article; and the assessments shall be collected as provided in sections ten and twelve of this article, and as paid and collected shall be applied to the liquidation of such bonds and the interest thereon; and if by reason of penalties collected with delinquent assessments there be any balance after the payment of such bonds and all accrued interest and cost, such balance shall be turned into the municipal treasury to the credit of the interest and sinking fund of the municipality: Provided, That no such municipality shall by sale or issuance of such bonds cause the aggregate of its indebtedness of every kind whatsoever to exceed five percent of the value of taxable property therein: Provided, however, That nothing herein contained shall be construed as authorizing any such municipality to become indebted in any other manner or for any purpose, to an amount, including its existing indebtedness, in the aggregate exceeding two and one-half percent of the value of the taxable property therein, as provided in section three, article one, chapter thirteen of this code, except for the purpose of grading, regrading, paving, repaving, surfacing, resurfacing, curbing, recurbing, building or renewing sidewalks, or constructing sewers or otherwise improving or reimproving the streets, alleys, public ways or easements, or sewer rights-of-way or easements, of such municipality, as provided for in this article; nor shall such municipality make such issuance and sale without at the same time providing for the collection of a direct annual tax sufficient to pay annually the interest on such debt and the principal thereof within and not exceeding ten years. All of the assessments, interest and penalties collected from the abutting property owners on account of the grading, regrading, paving, repaving, surfacing, resurfacing, curbing, recurbing, building or renewing sidewalks, or constructing sewers or otherwise improving or reimproving the streets, alleys, public ways or easements, or sewer rights-of-way or easements, of any such municipality, under the provisions of this article, shall annually be applied to the annual tax required to pay the interest on such debt and such principal within and not exceeding ten years; and in the event that the assessments, interest and penalties so collected do not amount to a sum sufficient to pay annually the interest on such debt and the principal thereof within and not exceeding ten years, then the governing body of such municipality shall collect so much of such levy as will pay annually the interest on such debt and the principal thereof within and not exceeding ten years.