BUSINESS COMBINATIONS We completed five acquisitions during 2018 that expanded our ready-mixed concrete operations in the Atlantic Region (which we define to include New York, New Jersey, Washington, D.C. and Pennsylvania) and expanded our ready-mixed concrete, aggregate products and other non-reportable operations in West Texas. The aggregate fair value consideration for these acquisitions, which were all accounted for as business combinations, was $70.8 million . The acquisitions included the assets and certain liabilities of the following:  On Time Ready Mix, Inc. (" On Time ") located in Flushing, New York on January 10, 2018 ;  Cutrell Trucking, LLC, Dumas Concrete, LLC, Pampa Concrete Co., Inc., Panhandle Concrete, LLC, and Texas Sand &amp; Gravel Co., Inc. (collectively " Golden Spread ") located in Amarillo, Texas on March 2, 2018 ;  Leon River Aggregate Materials, LLC ("Leon River") located in Proctor, Texas on August 29, 2018 ; and  Two individually immaterial ready-mixed concrete operations in our Atlantic Region and West Texas Region on March 5, 2018 and September 14, 2018 , respectively. The aggregate fair value consideration for these five acquisitions included $69.9 million in cash and fair value contingent consideration of $1.1 million and was net of a working capital receivable of $0.2 million . We funded the cash portion through a combination of cash on hand and borrowings under our Revolving Facility (as defined in Note 7 ). The combined assets acquired through these acquisitions included 149 mixer trucks, 20 concrete plant facilities and two aggregate facilities. To effect these transactions, during the three and nine months ended September 30, 2018 , we incurred $0.3 million and $0.9 million of transaction costs, respectively, which were included in selling and general administrative expenses in our condensed consolidated statements of operations. See Note 6 for a description of our measurement period adjustments. The following table presents the total consideration for the 2018 acquisitions and the amounts related to the assets acquired and liabilities assumed based on the estimated fair values as of their respective acquisition dates: ($ in millions) 2018 Acquisitions Inventory $ 1.1 Other current assets 0.1 Property, plant and equipment 37.4 Definite-lived intangible assets 19.8 Total assets acquired 58.4 Current liabilities 0.1 Other long-term liabilities 1.1 Total liabilities assumed 1.2 Goodwill 13.6 Total consideration (fair value) (1) $ 70.8 (1) Included $1.1 million of contingent consideration. Acquired Intangible Assets and Goodwill A summary of the intangible assets acquired in 2018 and their estimated useful lives is as follows: ($ in millions) Weighted Average Amortization Period (In Years) Fair Value At Acquisition Date Customer relationships 5.5 $ 18.5 Non-compete agreements 5.0 1.3 Total $ 19.8 As of September 30, 2019 , the estimated future aggregate amortization expense of definite-lived intangible assets from the 2018 acquisitions was as follows (in millions): 2019 (remainder of the year) $ 0.9 2020 3.6 2021 2.8 2022 2.6 2023 1.6 Thereafter 1.8 Total $ 13.3 During the three and nine months ended September 30, 2019 , we recorded $1.1 million and $3.6 million of amortization expense related to these intangible assets, respectively. For the three months ended September 30, 2019 , there were no measurement period adjustments related to these intangible assets. For the nine months ended September 30, 2019 , there were measurement period adjustments of $0.5 million related to these intangible assets. During the three and nine months ended September 30, 2018 , we recorded $1.1 million and $1.9 million of amortization expense related to these intangible assets, respectively. For the three and nine months ended September 30, 2018 , there were measurement period adjustments of $0.2 million and $0.3 million related to these intangible assets, respectively. The goodwill ascribed to the 2018 acquisitions is related to the synergies we expect to achieve with expansion in the markets in which we already operate as well as entry into new metropolitan areas of our existing geographic markets. The goodwill relates to our ready-mixed concrete and other non-reportable segments in the amounts of $12.8 million and $0.8 million , respectively. We generally expect all $13.6 million of goodwill from the 2018 acquisitions to be deductible for tax purposes. See Note 10 for additional information regarding income taxes. Impact of Acquisitions During the three months ended September 30, 2018 , we recorded $12.0 million of revenue and $1.4 million of operating loss in our condensed consolidated statements of operations related to the 2018 acquisitions following their respective dates of acquisition. During the nine months ended September 30, 2018 , we recorded approximately $33.6 million of revenue and $2.3 million of operating income in our condensed consolidated statements of operations related to the 2018 acquisitions following their respective dates of acquisition. The information presented below reflects the unaudited pro forma combined financial results for the 2018 acquisitions, excluding the individually immaterial acquisitions as described above, as historical financial results for these operations were not material and were impractical to obtain from the former owners. All other acquisitions have been included and represent our estimate of the 2018 results of operations as if the 2018 acquisitions had been completed on January 1, 2017. The impact to the 2019 results of operations if the 2018 acquisitions had been completed on January 1, 2017 was not materially different from our reported results. ($ in millions except per share) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Revenue $ 405.5 $ 1,153.1 Net income attributable to U.S. Concrete $ 15.2 $ 27.4 Net income per share attributable to U.S. Concrete - basic $ 0.92 $ 1.67 Net income per share attributable to U.S. Concrete - diluted $ 0.92 $ 1.66 The above pro forma results are unaudited and were prepared based on the historical U.S. GAAP results of the Company and the historical results of the acquired companies for which financial information was available, based on data provided by the former owners. These results are not necessarily indicative of what the Company's actual results would have been had the 2018 acquisitions occurred on January 1, 2017. The unaudited pro forma amounts above reflect the following adjustments: ($ in millions) Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Decrease (increase) in intangible amortization expense $ 0.2 $ (0.7 ) Exclusion of buyer transaction costs  0.7 Decrease in income tax expense 0.2 0.2 The unaudited pro forma results do not reflect any operational efficiencies or potential cost savings that may occur as a result of consolidation of the operations.