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Announcing the Development of the “Porous Polymer Mortar Method” Which Maintains Lasting Beauty of Pavement Bricks

—Application to roads such as those near art museums, in high-class residential areas, etc., which require a high degree of artistic design—

April 17, 2014Takenaka Corporation

Takenaka Road Construction Co., Ltd. (President: Shoji Fujimoto) and Takenaka Corporation (President: Masahiro Miyashita) have developed the “Porous Polymer Mortar Method” (patent pending) to maintain lasting beauty of pavement bricks that are widely used in sidewalks, plazas, etc. In this method, organic polymers (binding agents) that were developed jointly with Konishi Co., Ltd. (President: Takashi Yokota) are mixed with sand to form porous mortar※1, which is spread evenly to set the bricks into place.

※1 Mortar with many pores is highly water retentive


Comparison between the porous polymer mortar method and the cement mortar method

Porous Polymer Mortar Method

Porous Polymer Mortar Method

Cement Mortar Method

Cement Mortar Method

Usually before paving bricks are laid, a roadbed※2 is made by laying crushed stone, etc. on the ground surface, sand is poured on top of that, the roadbed is leveled, and the bricks are then laid in place. However, sometimes during a heavy rain, sand can run out of a steeply sloped area, while automobile traffic can cause the occurrence of unevenness or bumpiness.
Therefore, the cement mortar method was developed recently as a technique to use cement mortar in place of sand to prevent the occurrence of unevenness. However, the setting of the cement mortar layer has sometimes caused efflorescence※3 to occur, in which white stains appear on brick surfaces. Furthermore, when water retentive bricks are used as a measure to deal with the heat island effect, the lime in the cement may clog the pores of the bricks, which can reduce the water retention effect.
The new method does not use cement that contains lime, so efflorescence does not occur, and the water retention effect can be maintained. It is also possible to maintain the original beauty for many years.


※2 A foundation containing crushed stone, gravel, sand, etc., that is laid between the subgrade and the paved surface of the road.
※3 Lime contained in the cement appears on surfaces.

This technique has already been used at two sites in Japan. We propose that it be used wherever a high artistic sense is desired, such as in roads near museums, high-class residential areas, etc., regardless of whether it is new construction or renovation.


Comparison with conventional methods (features of the new method)

Comparison with cases where sand is used Comparison with cases where cement is used
・Bumpiness does not occur
・Load bearing capacity is improved
・ Efflorescence does not occur
・ No labor or money is needed to clean stains caused by efflorescence
・ Maintains the effectiveness of water-retentive bricks
・ Special measurements are not needed because it is a one-part organic binding agent.


Method for laying bricks

1) Crushed stone (roadbed) is laid, rolled and leveled.
2) Sand is mixed into the polymer (binding agent) to create the porous polymer mortar.
3) The porous polymer mortar is spread evenly on top of the crushed stone.
4) The bricks are laid, rolled, and leveled.
Creating the mortar

Creating the mortar

Compressing the bricks

Compressing the bricks

Spreading the mortar evenly

Spreading the mortar evenly

Laying bricks

Laying bricks

Market size

In 2012, the market size for interlocking concrete bricks used for paving was 2.86 million m2. Of this total, 80 percent was used for pedestrian walkways, bicycle paths, and plazas (source: Japan Interlocking Block Pavement Engineering Association)