Lumps and balls in high-slump concrete: reasons and remedy

The objective of this research was to investigate the reason lumps occur in high-slump concrete and develop adequate batching procedures for a lumps-free high-slump ready-mix concrete mix used by the Florida Department of Transportation. Cement balls are round lumps of cement, sand, and coarse aggregate, typically about the size of a baseball that frequently occur in high-slump concrete. Such lumps or balls jeopardize the structural integrity of structural members. Experiments were conducted at the CSR Rinker concrete plant in Miami, Florida, based on a protocol developed by a team of Florida Department of Transportation (FDOT) concrete engineers, Rinker personnel, and Florida International University faculty. A total of seventeen truckloads were investigated in two phases, between April 2001 and March 2002. The tests consisted of gathering data by varying load size, discharge rate, headwater content, and mixing revolutions. The major finding was that a usual load size and discharge rate, an initial headwater ratio of 30%, and an initial number of revolutions of 100 at 12 revolutions per minute seem to produce a lump-free high-slump concrete. It was concluded that inadequate mixing and batching procedures caused cement lumps. Recommendations regarding specific load size, discharge rates, number of mixing revolutions, and initial water content are made. Clear guidelines for a high-slump concrete batching protocol can be developed, with further testing based on these research conclusions.

Managua Relief

Bob del Toro, Dianne Haley and Others with Toys for Managuan Relief. On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum 887-3400. april 30, 1973. Cutlines: More than 350 dozens of various balls, skate boards and games were recently purchased by the Student Governance Committee of Florida International University for the young people of Managua, Nicaragua who not only do not have enough toys but are unable to attend schools which are closed. Left to right are, Bob del Toro, Dianne Haley, Chairman of the Student Governance Committee, Hialeah Councilman Jack Weaver of the Hialeah-Managua Sister City Committee, Barbara O'Nan and Margaret Klein.

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum From: City of Hialeah Publicity Bureu. 401 1/2 East 1st Ave. Hialeah, Fla. 887-3400. april 30, 1973. Cutlines: Florida International University students recently raised more than $ 1,000 for more than 300 dozens toys and balls for the youngsters of Managua, Nicaragua. With the balls above are shown student Committee members and oficials of the Hialeah-Managua Sister City Committee, left to rigth: Bob del Toro, Sister City Committe president Raymond R. Schultz, Student Governance Committee chairman Dianne Haley and Hialeah City councilman Jack Weaver.

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements by organizations were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum From: City of Hialeah Publicity Bureu. 401 1/2 East 1st Ave. Hialeah, Fla. 887-3400. april 30, 1973. Cutlines: Skate boards, paddle balls and flying saucers were among the big shipment of toys which was recently dispatched to Managua, Nicaragua by students of Florida International University through the Hialeah-Managua Sister Committee. Examining the toys above are, left to right: Margaret Klein, Hialeah councilman Jack Weaver and Barbara O'Nan.

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum

Managua Relief

On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum

Managua Relief

The Miami News. Mon., March 19, 1973. Managuan Relief. Miami News Staff Photo by George Kochaniec. Raymond and Connie Schultz with toys. (Back) "Focuses on kids" article On December 23, 12:29 a.m. local time in Managua, Nicaragua, a magnitude 6.2 earthquake occurred. The earth caused widespread damage among Managua, the capital city. In Managua, 5,000 residents were killed, 20,000 were injured and over 250,000 were left homeless. In Miami, residents and relief organizations focused on helping children. Wife of General Arturo Somoza pleaded on efforts on gathering sporting goods and toys for Managua’s young people. Relief committees purchased 230 dozen balls – basketball, rubber, and volley, soccer, and others. Nearly $500 came from students in Hialeah High School. Jump ropes and jacks were donated from a sorority at Florida International University. Arrangements were made to bring 44,000 pounds of baby formula and canned meat and 13,000 pounds of medicine. Many of Miami’s corporations, associations, and residents contributed to the Managuan Relief effort. Source: The Miami News, March 19, 1973 by Lynn Feigenbaum