Mo. Rev. Stat. § 231.260
Any contractor who shall willfully fail or neglect to keep any road under his care in good repair, or shall in any manner fail or neglect to keep any road under his care in good repair, or shall in any manner fail to faithfully perform or discharge any of his duties according to the terms of his contract, or shall willfully fail or refuse after five days' notice to repair any bridge or culvert which under the terms of the contract it is his duty to repair, shall be held responsible upon his said bond for any and all damages which occur to persons or property by reason of such failure; provided, that nothing herein contained shall prevent the contractor from pleading as a defense for such failure to perform his work in the time specified in the contract that same was caused by unusual weather and that with due care and diligence he could not have avoided such delay.
§ 231.260, RSMo